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17 pages, 12382 KiB

Open AccessArticle

Microwave Irradiation-Assisted Synthesis of Anisotropic Crown Ether-Grafted Bamboo Pulp Aerogel as a Chelating Agent for Selective Adsorption of Heavy Metals (Mⁿ⁺)

by Wenxiang Jing, Min Tang, Xiaoyan Lin, Chai Yang, Dongming Lian, Ying Yu and Dongyang Liu

Gels 2024, 10(12), 778; https://doi.org/10.3390/gels10120778 (registering DOI) - 28 Nov 2024

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Abstract

Crown ether is widely used in water purification because of its ring structure and good selective adsorption of specific heavy metals. However, its high cost and difficulty in recycling limit the purification of heavy metals in water. The anisotropic [2,4]-dibenzo-18-crown-6-modified bamboo pulp aerogel [...] Read more.

Crown ether is widely used in water purification because of its ring structure and good selective adsorption of specific heavy metals. However, its high cost and difficulty in recycling limit the purification of heavy metals in water. The anisotropic [2,4]-dibenzo-18-crown-6-modified bamboo pulp aerogel (DB18C6/PA) is successfully synthesized by microwave irradiation and directional freezing technology. The physical and chemical properties of DB18C6/PA are analyzed by FTIR, XPS, SEM, TEM, TGA, surface area and porosity analyzers. Single or multivariate systems containing Pb²⁺, Cu²⁺ and Cd²⁺ are used as adsorbents. The effects of the DB18C6 addition amount, pH, initial concentration and adsorption temperature on the adsorption of DB18C6/PA are systematically explored. Pseudo-first-order kinetic models, pseudo-second-order kinetic models and the isothermal adsorption models of Langmuir and Freundlich are used to fit the experimental data. The adsorption selectivity is analyzed from the distribution coefficient and the separation factor, and the adsorption mechanism is discussed. The results show that anisotropic DB18C6/PA has the characteristics of 3D directional channels, high porosity (97.67%), large specific surface area (103.7 m²/g), good thermal stability and regeneration (the number of cycles is greater than 5). The surface has a variety of functional groups, including a hydroxyl group, aldehyde group, ether bond, etc. In the single and multivariate systems of Pb²⁺, Cu²⁺ and Cd²⁺, the adsorption process of DB18C6/PA conforms to the pseudo-second-order kinetic model, and the results conform to the Freundlich adsorption isothermal model (a few of them conformed to the Langmuir adsorption isothermal model), indicating that chemical adsorption and physical adsorption are involved in the adsorption process, and the adsorption process is a spontaneous endothermic process. In the single solution system, the maximum adsorption capacities of Pb²⁺, Cu²⁺ and Cd²⁺ by DB18C6/PA are 129.15, 29.85 and 27.89 mg/g, respectively. The adsorption selectivity of DB18C6/PA on Pb²⁺, Cu²⁺ and Cd²⁺ is in the order of Pb²⁺ >> Cu²⁺ > Cd²⁺. Full article

(This article belongs to the Special Issue Advances in Synthetic and Bio-Based Aerogels: Mechanical Properties, Thermal Insulation, and Environmental Remediation)

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(a) SEM images of DB18C6; (b,c) SEM spectra of DB18C6/PA1-2 obtained by non-directional freezing with different magnification; (d,e) SEM spectra of DB18C6/PA1-2 obtained by directional freezing with different magnifications; (f) TEM of DB18C6/PA1-2 obtained by directional freezing; (g) Digital photos of bamboo pulp aerogel obtained under different preparation conditions; (h) Schematic diagram of DB18C6/PA structure; (i) N2 adsorption–desorption isotherm curve of DB18C6/PA; (j) Pore size distribution of DB18C6/PA. Full article ">Figure 2
XPS spectra of DB18C6/PA: (a) full spectrum, (b) C1s spectrum of DB18C6/PA1-1, (c) C1s spectrum of DB18C6/PA1-2, (d) C1s spectrum of DB18C6/PA1-3; (e) TGA and (f) DTG of DB18C6/PA. Full article ">Figure 3
Effect of DB18C6/PA obtained by non-directional freezing and directional freezing on adsorption of (a) Pb2+, (b) Cu2+, and (c) Cd2+. Effect of DB18C6/PA obtained with different (d) microwave power and (e) reaction time on the adsorption of Pb2+, Cu2+ and Cd2+. The effect of (f) pH and (g) initial concentration on the adsorption of Pb2+, Cu2+ and Cd2+ by DB18C6/PA. Full article ">Figure 4
The fitted curves of adsorption kinetics models for Pb2+ in the single, binary and ternary systems of (a) Pb2+, (b) Pb2+/Cu2+, (c) Pb2+/Cd2+, (d) Pb2+/Cu2+/Cd2+; Cu2+ in the single, binary and ternary systems of (e) Cu2+, (f) Cu2+/Pb2+, (g) Cu2+/Cd2+, (h) Cu2+/Pb2+/Cd2+; Cd2+ in the single, binary and ternary system of (i) Cd2+, (j) Cd2+/Pb2+, (k) Cd2+/Cu2+, (l) Cd2+/Pb2+/Cu2+, on the DB18C6/PA, at pH = 5 and temperature = 25 °C. Full article ">Figure 5
The fitted curves of adsorption isothermal models for Pb2+ in the single, binary and ternary systems of (a) Pb2+, (b) Pb2+/Cu2+, (c) Pb2+/Cd2+, (d) Pb2+/Cu2+/Cd2+; Cu2+ in the single, binary and ternary systems of (e) Cu2+, (f) Cu2+/Pb2+, (g) Cu2+/Cd2+, (h) Cu2+/Pb2+/Cd2+; Cd2+ in the single, binary and ternary system of (i) Cd2+, (j) Cd2+/Pb2+, (k) Cd2+/Cu2+, (l) Cd2+/Pb2+/Cu2+ on the DB18C6/PA. Full article ">Figure 6
Adsorption mechanism of DB18C6/PA on Pb2+, Cu2+ and Cd2+. Full article ">Figure 7
Removal efficiency of Pb2+, Cu2+ and Cd2+ by DB18C6/PA for 5 adsorption–desorption cycles. Full article ">

15 pages, 4134 KiB

Open AccessArticle

Nanostructured Hydrogels of Carboxylated Cellulose Nanocrystals Crosslinked by Calcium Ions

by Alexander S. Ospennikov, Yuri M. Chesnokov, Andrey V. Shibaev, Boris V. Lokshin and Olga E. Philippova

Gels 2024, 10(12), 777; https://doi.org/10.3390/gels10120777 (registering DOI) - 28 Nov 2024

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Abstract

Bio-based eco-friendly cellulose nanocrystals (CNCs) gain an increasing interest for diverse applications. We report the results of an investigation of hydrogels spontaneously formed by the self-assembly of carboxylated CNCs in the presence of CaCl₂ using several complementary techniques: rheometry, isothermal titration calorimetry, [...] Read more.

Bio-based eco-friendly cellulose nanocrystals (CNCs) gain an increasing interest for diverse applications. We report the results of an investigation of hydrogels spontaneously formed by the self-assembly of carboxylated CNCs in the presence of CaCl₂ using several complementary techniques: rheometry, isothermal titration calorimetry, FTIR-spectroscopy, cryo-electron microscopy, cryo-electron tomography, and polarized optical microscopy. Increasing CaCl₂ concentration was shown to induce a strong increase in the storage modulus of CNC hydrogels accompanied by the growth of CNC aggregates included in the network. Comparison of the rheological data at the same ionic strength provided by NaCl and CaCl₂ shows much higher dynamic moduli in the presence of CaCl₂, which implies that calcium cations not only screen the repulsion between similarly charged nanocrystals favoring their self-assembly, but also crosslink the polyanionic nanocrystals. Crosslinking is endothermic and driven by increasing entropy, which is most likely due to the release of water molecules surrounding the interacting COO⁻ and Ca²⁺ ions. The hydrogels can be easily destroyed by increasing the shear rate because of the alignment of rodlike nanocrystals along the direction of flow and then quickly recover up to 90% of their viscosity in 15 s, when the shear rate is decreased. Full article

(This article belongs to the Special Issue Advances in Cellulose-Based Hydrogels (3rd Edition))

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17 pages, 3866 KiB

Open AccessArticle

Preparation and Rheological Evaluation of Thiol–Maleimide/Thiol–Thiol Double Self-Crosslinking Hyaluronic Acid-Based Hydrogels as Dermal Fillers for Aesthetic Medicine

by Chia-Wei Chu, Wei-Jie Cheng, Bang-Yu Wen, Yu-Kai Liang, Ming-Thau Sheu, Ling-Chun Chen and Hong-Liang Lin

Gels 2024, 10(12), 776; https://doi.org/10.3390/gels10120776 (registering DOI) - 28 Nov 2024

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Abstract

This study presents the development of thiol–maleimide/thiol–thiol double self-crosslinking hyaluronic acid-based (dscHA) hydrogels for use as dermal fillers. Hyaluronic acid with varying degrees of maleimide substitution (10%, 20%, and 30%) was synthesized and characterized, and dscHA hydrogels were fabricated using [...] Read more.

This study presents the development of thiol–maleimide/thiol–thiol double self-crosslinking hyaluronic acid-based (dscHA) hydrogels for use as dermal fillers. Hyaluronic acid with varying degrees of maleimide substitution (10%, 20%, and 30%) was synthesized and characterized, and dscHA hydrogels were fabricated using two molecular weights of four-arm polyethylene glycol (PEG10K/20K)–thiol as crosslinkers. The six resulting dscHA hydrogels demonstrated solid-like behavior with distinct physical and rheological properties. SEM analysis revealed a decrease in porosity with higher crosslinker MW and maleimide substitution. The swelling ratios of the six hydrogels reached equilibrium at approximately 1 h and ranged from 20% to 35%, indicating relatively low swelling. Degradation rates decreased with increasing maleimide substitution, while crosslinker MW had little effect. Higher maleimide substitution also required greater injection force. Elastic modulus (G′) in the linear viscoelastic region increased with maleimide substitution and crosslinker MW, indicating enhanced firmness. All hydrogels displayed similar creep-recovery behavior, showing instantaneous deformation under constant stress. Alternate-step strain tests indicated that all six dscHA hydrogels could maintain elasticity, allowing them to integrate with the surrounding tissue via viscous deformation caused by the stress exerted by changes in facial expression. Ultimately, the connection between the clinical performance of the obtained dscHA hydrogels used as dermal filler and their physicochemical and rheological properties was discussed to aid clinicians in the selection of the most appropriate hydrogel for facial rejuvenation. While these findings are promising, further studies are required to assess irritation, toxicity, and in vivo degradation before clinical use. Overall, it was concluded that all six dscHA hydrogels show promise as dermal fillers for various facial regions. Full article

(This article belongs to the Special Issue Recent Research on Medical Hydrogels)

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1H NMR (A) and FTIR spectra (B) of HA and HA-Mal with three different degrees of substitution of maleimide on HA (HM10, HM20, and HM30). Full article ">Figure 2
Reaction scheme illustrating the formation of dscHA hydrogels. Full article ">Figure 3
SEM images of six dscHA hydrogels (HM10-4SH10K (A), HM20-4SH10K (B), HM30-4SH10K (C), HM10-4SH20K (D), HM20-4SH20K (E), and HM30-4SH20K (F). (Scale bar: 500 µm). Full article ">Figure 4
The swelling ratio profiles (A) and degradation profiles (B) for HAs with various levels of maleimide substitution and thiol-containing crosslinkers with two different MWs (designated as HM10-4SH10K, HM10-4SH20K, HM20-4SH10K, HM20-4SH20K, HM30-4SH10K, and HM30-4SH20K, respectively). Full article ">Figure 5
Injection force through a 26 G needle measured for six dscHA hydrogels (HM10-4SH10K, HM10-4SH20K, HM20-4SH10K, HM20-4SH20K, HM30-4SH10K, and HM30-4SH20K). Full article ">Figure 6
Rheological evaluation of dscHA hydrogels. Amplitude sweep (A) and frequency sweep (B) of the six dscHA hydrogels, showing the linear viscoelastic (LVE) region and gel behavior. Tan δ values (C) of the six dscHA hydrogels, indicating whether the behavior is elastic-dominant or viscous-dominant. Full article ">Figure 7
Creep-recovery experiments (constant stress) were performed with an applied shear stress of 5 Pa for 10 min followed by 20 min of recovery (A), and alternate-step strain tests with five repetitions of shear-stress application and relaxation (B) were performed to study the deformation and recovery of the hydrogel network. Full article ">

18 pages, 9457 KiB

Open AccessArticle

Novel Injectable Collagen/Glycerol/Pullulan Gel Promotes Osteogenic Differentiation of Mesenchymal Stem Cells and the Repair of Rat Cranial Defects

by Xin Wang, Satoshi Komasa, Yoshiro Tahara, Shihoko Inui, Michiaki Matsumoto and Kenji Maekawa

Gels 2024, 10(12), 775; https://doi.org/10.3390/gels10120775 (registering DOI) - 28 Nov 2024

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Abstract

Bone tissue engineering is a technique that simulates the bone tissue microenvironment by utilizing cells, tissue scaffolds, and growth factors. The collagen hydrogel is a three-dimensional network bionic material that has properties and structures comparable to those of the extracellular matrix (ECM), making [...] Read more.

Bone tissue engineering is a technique that simulates the bone tissue microenvironment by utilizing cells, tissue scaffolds, and growth factors. The collagen hydrogel is a three-dimensional network bionic material that has properties and structures comparable to those of the extracellular matrix (ECM), making it an ideal scaffold and drug delivery system for tissue engineering. The clinical applications of this material are restricted due to its low mechanical strength. In this investigation, a collagen-based gel (atelocollagen/glycerol/pullulan [Col/Gly/Pul] gel) that is moldable and injectable with high adhesive qualities was created by employing a straightforward technique that involved the introduction of Gly and Pul. This study aimed to characterize the internal morphology and chemical composition of the Col/Gly/Pul gel, as well as to verify its osteogenic properties through in vivo and in vitro experiments. When compared to a standard pure Col hydrogel, this material is more adaptable to the complexity of the local environment of bone defects and the apposition of irregularly shaped flaws due to its greater mechanical strength, injectability, and moldability. Overall, the Col/Gly/Pul gel is an implant that shows great potential for the treatment of complex bone defects and the enhancement of bone regeneration. Full article

(This article belongs to the Special Issue Development of Nanogels/Microgels for Regenerative Medicine)

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(A) Fourier-transform infrared spectra: (a) pullulan (Pul), (b) atelocollagen (Col), (c) Col/Gly/Pul gel, and (d) glycerol (Gly). (B,C) Thixotropic studies of Col/Gly/Pul gel and standard liquid. (D) Swelling behavior of the Col/Gly/Pul gel. (E) Amplitude-strain, (F) frequency, and (G) tan δ (G″/G′) of frequency sweeps. LVR, linear viscoelastic region. (H) Images showing the moldability and injectability of the Col/Gly/Pul gel. Full article ">Figure 2
(A) Scanning electron micrographs, and (B) pore size distribution. (C) The cell viability of rBMSCs initial adherent to the control, Col gel, and Col/Gly/Pul gel. Not significant (ns): p ≥ 0.05; ***: p < 0.001; ****: p < 0.0001. (D) In vitro degradation of the Col/Gly/Pul gel and Col gel. Full article ">Figure 3
Morphology of rBMSCs attached to the control, Col gel, and Col/Gly/Pul gel after 24 h of incubation. Nuclei were labeled with DAPI (blue), and actin filaments stained with Phalloidin (green). Images obtained at a lower magnification (A) show the number and distribution of cells (scale bars = 100 µm), whereas those obtained at a higher magnification (B) show the connections among cells attached to the different samples (white arrows indicate interactions among cells; scale bars = 50 µm). Full article ">Figure 4
(A–C) The real-time PCR analysis of specific osteogenesis-related gene expression on the control, Col gel, and Col/Gly/Pul gel. (D) Alkaline phosphatase (ALP) activity and (E) calcium deposition on the control, Col gel, and Col/Gly/Pul gel. Not significant (ns): p ≥ 0.05; *: p < 0.05; **: p < 0.01; ***: p < 0.001; ****: p < 0.0001. (F) Alizarin Red staining of the control, Col gel, and Col/Gly/Pul gel (white arrows indicate bone nodules). Full article ">Figure 5
Effect of the Col/Gly/Pul gel on bone formation in a rat cranial defect model. (A) Treatment protocol for cranial bone defects in rats. Briefly, after separating the periosteum, a 5 mm cylinder-shaped bone defect was prepared on both sides of the sagittal midline of the rat parietal bone and then treated with or without gel. (B) Reconstructed three-dimensional micro-CT images of bone tissues after eight weeks. (C) Bone mineral density (BMD), (D) bone volume-to-total volume ratio (BV/TV), (E) trabecular number (Tb. N), (F) bone surface-to-bone volume ratio (BS/BV), and (G) trabecular separation (Tb. Sp) around the control, Col gel, and Col/Gly/Pul gel after eight weeks. Not significant (ns): p ≥ 0.05; *: p < 0.05; **: p < 0.01; ***: p < 0.001; ****: p < 0.0001. Full article ">Figure 6
Sirius red stain sections of bone tissues after eight weeks around the (A,a,b) Control, (B,c,d) Col gel, and (C,e,f) Col/Gly/Pul gel. Mature, regular fibrous groups were marked by white arrows; immature, disorganized fibrous tissues marked by blue arrows; and the boundary between the old and new bone marked by black arrows. Full article ">Figure 7
Schematic illustration of the principle of the Col/Gly/Pul gel to promote bone regeneration and repair. (A) Col/Gly/Pul gel provides a scaffold for cell growth. (B) Col/Gly/Pul gel provides mechanical stimuli to the cells and facilitates the diffusion of nutrients. (C) Col/Gly/Pul gel promotes osteogenic differentiation through multiple signaling pathways. (D) Regeneration of new bone tissue with degradation of the Col/Gly/Pul gel. This figure was drawn using Figdraw. Full article ">Scheme 1
Schematic diagram of the design and preparation of an injectable gel composed of atelocollagen, glycerol, and pullulan (Col/Gly/Pul). (A) Col, Gly, and Pul were stirred at room temperature (23–25 °C) for 5 h. (B) The mixture was frozen at −80 °C for 30 min. (C) The material was dried with a freeze dryer for 12 h. (D) Injectable state of the Col/Gly/Pul gel. (E) Col/Gly/Pul gel before swelling. (F) Network of the swollen Col/Gly/Pul gel. Full article ">

16 pages, 7199 KiB

Open AccessArticle

CO₂ Foamed Viscoelastic Gel-Based Seawater Fracturing Fluid for High-Temperature Wells

by Jawad Al-Darweesh, Murtada Saleh Aljawad, Muhammad Shahzad Kamal, Mohamed Mahmoud, Shabeeb Alajmei, Prasad B. Karadkar and Bader G. Harbi

Gels 2024, 10(12), 774; https://doi.org/10.3390/gels10120774 (registering DOI) - 27 Nov 2024

Viewed by 258

Abstract

This study investigates the development of a novel CO₂-foamed viscoelastic gel-based fracturing fluid to address the challenges of high-temperature formations. The influence of various parameters, including surfactant type and concentration, gas fraction, shear rate, water salinity, temperature, and pressure, on foam [...] Read more.

This study investigates the development of a novel CO₂-foamed viscoelastic gel-based fracturing fluid to address the challenges of high-temperature formations. The influence of various parameters, including surfactant type and concentration, gas fraction, shear rate, water salinity, temperature, and pressure, on foam viscosity was systematically explored. Rheological experiments were conducted using a high-pressure/high-temperature (HPHT) rheometer at 150 °C and pressures ranging from 6.89 to 20.68 MPa. To simulate field conditions, synthetic high-salinity water was employed. The thermal stability of the CO₂ foam was evaluated at a constant shear rate of 100 1/s for 180 min. Additionally, foamability and foam stability were assessed using an HPHT foam analyzer at 100 °C. The results demonstrate that liquid phase chemistry, experimental conditions, and gas fraction significantly impact foam viscosity. Viscoelastic surfactants achieved a peak foam viscosity of 0.183 Pa·s at a shear rate of 100 1/s and a 70% foam quality, surpassing previous records. At lower foam qualities (≤50%), pressure had a negligible effect on foam viscosity, whereas at higher qualities, it increased viscosity by over 30%. While a slight increase in viscosity was observed with foam qualities between 40% and 60%, a significant enhancement was noted at 65% foam quality. The addition of polymers did not improve foam viscosity. The generation of viscous and stable foams is crucial for effective proppant transport and fracture induction. However, maintaining the thermal stability of CO₂ foams with minimal additives remains a significant challenge in the industry. This laboratory study provides valuable insights into the development of stable CO₂ foams for stimulating high-temperature wells. Full article

(This article belongs to the Special Issue Gels for Oil and Gas Industry Applications (3rd Edition))

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20 pages, 3196 KiB

Open AccessArticle

Reinforcement of Dextran Methacrylate-Based Hydrogel, Semi-IPN, and IPN with Multivalent Crosslinkers

by Luca Paoletti, Gianluca Ferrigno, Nicole Zoratto, Daniela Secci, Chiara Di Meo and Pietro Matricardi

Gels 2024, 10(12), 773; https://doi.org/10.3390/gels10120773 - 27 Nov 2024

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Abstract

The need for new biomaterials to meet the needs of advanced healthcare therapies is constantly increasing. Polysaccharide-based matrices are considered extremely promising because of their biocompatibility and soft structure; however, their use is limited by their poor mechanical properties. In this light, a [...] Read more.

The need for new biomaterials to meet the needs of advanced healthcare therapies is constantly increasing. Polysaccharide-based matrices are considered extremely promising because of their biocompatibility and soft structure; however, their use is limited by their poor mechanical properties. In this light, a strategy for the reinforcement of dextran-based hydrogels and interpenetrated polymer networks (semi-IPNs and IPNs) is proposed, which will introduce multifunctional crosslinkers that can modify the network crosslinking density. Hydrogels were prepared via dextran methacrylation (DexMa), followed by UV photocrosslinking in the presence of diacrylate (NPGDA), triacrylate (TMPTA), and tetraacrylate (PETA) crosslinkers at different concentrations. The effect of these molecules was also tested on DexMa-gellan semi-IPN (DexMa/Ge) and, later, on IPN (DexMa/CaGe), obtained after solvent exchange with CaCl₂ in HEPES and the resulting Ge gelation. Mechanical properties were investigated via rheological and dynamic mechanical analyses to assess the rigidity, resistance, and strength of the systems. Our findings support the use of crosslinkers with different functionality to modulate the properties of polysaccharide-based scaffolds, making them suitable for various biomedical applications. While no significative difference is observed on enriched semi-IPN, a clear improvement is visible on DexMa and DexMa/CaGe systems when TMPTA and NPGDA crosslinker are introduced at higher concentrations, respectively. Full article

(This article belongs to the Special Issue Rheological Properties and Applications of Gel-Based Materials)

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Scheme of DexMa hydrogels’ (A) and semi-IPNs’ (B) formation, in the presence of diacrylate, triacrylate, and tetraacrylate crosslinkers, after UV photocrosslinking. Full article ">Figure 2
Dynamic mechanical analysis of DexMa systems. Young’s modulus [E] of DexMa, DexMa-NPGDA, DexMa-TMPTA, and DexMa-PETA hydrogels in a ratio of 10:1 (A), 4:1 (B), and 2:1 (C). Maximum stress registered at the breaking point of DexMa, DexMa-NPGDA, DexMa-TMPTA, and DexMa-PETA hydrogels in a ratio of 10:1 (D), 4:1 (E), and 2:1 (F). Data are expressed as the mean value ± standard deviation; experiments were performed in triplicate (n = 3). p values were obtained via two-way ANOVA and Dunnett’s multiple comparisons test (**** p < 0.0001; *** p < 0.001; ** p < 0.01; * p < 0.05). Full article ">Figure 3
Hydrogel rheological analysis, showing the shear storage modulus (G′) at a frequency of 1 Hz, of DexMa, DexMa-NPGDA, DexMa-TMPTA, and DexMa-PETA prepared with a molar ratio of 10:1 (A), 4:1 (B), and 2:1 (C). Tan(delta) loss factor (G″/G′) at 1 Hz of hydrogels obtained with a ratio of 10:1 (D), 4:1 (E), and 2:1 (F). Data are expressed as the mean value ± standard deviation; experiments were performed in triplicate (n = 3). p values were obtained via two-way ANOVA and Dunnett’s multiple comparisons test (**** p < 0.0001; *** p < 0.001; ** p < 0.01; * p < 0.05). Full article ">Figure 4
Dynamic mechanical analysis of DexMa/Ge semi-IPNs. Young’s modulus [E] of DexMa/Ge, DexMa-NPGDA/Ge, DexMa-TMPTA/Ge, and DexMa-PETA/Ge semi-IPNs obtained with a 4:1 (A) and 2:1 (B) ratio. Maximum stress registered at the breaking point of DexMa/Ge, DexMa-NPGDA/Ge, DexMa-TMPTA/Ge, and DexMa-PETA/Ge semi-IPNs in a ratio of 4:1 (C) and 2:1 (D). Data are expressed as the mean value ± standard deviation; experiments were performed in triplicate (n = 3). p values were obtained via two-way ANOVA and Dunnett’s multiple comparisons test (**** p < 0.0001; *** p < 0.001; ** p < 0.01; * p < 0.05). Full article ">Figure 5
Semi-IPN rheological analysis, showing the shear storage modulus (G′) at a frequency of 1 Hz of DexMa/Ge, DexMa-NPGDA/Ge, DexMa-TMPTA/Ge, and DexMa-PETA/Ge obtained with a molar ratio of 4:1 (A) and 2:1 (B). Tan(delta) loss factor (G″/G′) at 1 Hz of semi-IPN obtained with a ratio of 4:1 (C) and 2:1 (D). Data are expressed as the mean value ± standard deviation; experiments were performed in triplicate (n = 3). p values were obtained via two-way ANOVA and Dunnett’s multiple comparisons test (**** p < 0.0001; *** p < 0.001; ** p < 0.01; * p < 0.05). Full article ">Figure 6
Rheological analysis of DexMa/CaGe, DexMa-NPGDA/CaGe, and DexMa-TMPTA/CaGe IPNs obtained with a 2:1 ratio (A), showing the shear storage modulus (G′) at a frequency of 1 Hz (full bars) and tan(delta) loss factor (G″/G′) at 1 Hz (striped bars). Dynamic mechanical analysis (B): Young’s modulus [E] of DexMa/CaGe, DexMa-NPGDA/CaGe, and DexMa-TMPTA/CaGe IPNs obtained with a 2:1 ratio (full bars) and maximum stress registered at the breaking point (striped bars). Data are expressed as the mean value ± standard deviation; experiments were performed in triplicate (n = 3). p values were obtained via two-way ANOVA and Dunnett’s multiple comparisons test (**** p < 0.0001; ** p < 0.01; * p < 0.05). Full article ">

19 pages, 2547 KiB

Open AccessArticle

The Effect of a Nature-Based Gel on Gingival Inflammation and the Proteomic Profile of Crevicular Fluid: A Randomized Clinical Trial

by Luciene Cristina Figueiredo, Bruno Bueno-Silva, Giovanna Denúncio, Nathalia Freitas Figueiredo, Daniele Ferreira da Cruz, Jamil A. Shibli, Maria Helena R. Borges, Valentim A. R. Barão, Doron Haim, Thabet Asbi and João Gabriel S. Souza

Gels 2024, 10(12), 772; https://doi.org/10.3390/gels10120772 - 27 Nov 2024

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Abstract

Evidence has shown the clear positive effects of nature-based products on biofilm control and improved gingival health. However, most studies have used in vitro models, have tested single natural components, or have not evaluated proteomic changes after treatment. This double-blind, parallel, randomized, and [...] Read more.

Evidence has shown the clear positive effects of nature-based products on biofilm control and improved gingival health. However, most studies have used in vitro models, have tested single natural components, or have not evaluated proteomic changes after treatment. This double-blind, parallel, randomized, and controlled clinical trial evaluated the benefits of a nature-based gel in controlling gingival inflammation and its effects on the proteomic gingival crevicular fluid (GCF) profile. Gingivitis patients were distributed into the following groups: (1) nature-based gel containing propolis, aloe vera, green tea, cranberry, and calendula (n = 10); (2) control—conventional toothpaste (n = 10). GCF was collected and evaluated by means of liquid chromatography coupled with tandem mass spectrometry (LC–MS/MS). At 3 months, the groups showed similar clinical benefits (p < 0.05). A total of 480 proteins were identified across all groups. In a pooled comparison of both groups at both time points, exclusive proteins were identified in the nature-based gel (78) and the control (21) groups. The exclusive proteins identified for the toothpaste mainly acted in wound healing, and those for the nature-based gel mainly acted on immune system processes. The nature-based gel achieved similar clinical outcomes to conventional toothpaste. However, the nature-based gel markedly changed the proteomic profile of GCF after treatment, showing a profile associated with a host response. Full article

(This article belongs to the Special Issue Designing Gels for Antibacterial and Antiviral Agents)

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19 pages, 5417 KiB

Open AccessArticle

Effect of Carrot Callus Cells on the Mechanical, Rheological, and Sensory Properties of Hydrogels Based on Xanthan and Konjac Gums

by Elena Günter, Oxana Popeyko, Fedor Vityazev, Natalia Zueva, Inga Velskaya and Sergey Popov

Gels 2024, 10(12), 771; https://doi.org/10.3390/gels10120771 - 27 Nov 2024

Viewed by 190

Abstract

The study aims to develop a plant-based food gel with a unique texture using callus cells and a mixture of xanthan (X) and konjac (K) gums. The effect of encapsulation of carrot callus cells (0.1 and 0.2 g/mL) on properties of X-K hydrogels [...] Read more.

The study aims to develop a plant-based food gel with a unique texture using callus cells and a mixture of xanthan (X) and konjac (K) gums. The effect of encapsulation of carrot callus cells (0.1 and 0.2 g/mL) on properties of X-K hydrogels was studied using the mechanical and rheological analysis with a one-way ANOVA and Student’s t-test used for statistical analysis. Hedonic evaluation and textural features were obtained from 35 volunteers using a nine-point hedonic scale and a 100 mm visual analog scale with the Friedman’s test and the Durbin post hoc test used for statistical analysis. Mechanical hardness, gumminess, and elasticity increased by 1.1–1.3 and 1.1–1.8 times as a result of encapsulation 0.1 and 0.2 g/mL cells, respectively. The addition of cells to the hydrogels resulted in an increase in the complex viscosity, strength, and number of linkages in the gel. The hydrogel samples received identical ratings for overall and consistency liking, as well as taste, aroma, and texture features. However, the callus cell-containing hydrogel had a graininess score that was 82% higher than the callus cell-free hydrogel. The obtained hydrogels based on gums and immobilized carrot callus cells with unique textures may be useful for the development of diverse food textures and the production of innovative functional foods. Full article

(This article belongs to the Special Issue Recent Developments in Food Gels (2nd Edition))

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Нardness (a), cohesiveness (b), gumminess (c), elasticity (d), springiness (e), and chewiness (f) of hydrogels based on an aqueous mixture of xanthan (X) and konjac (K) gums. The data are presented as the mean ± S.D., n = 12. Different lowercase letters (a, b, and c) indicate significant differences (p < 0.05) between the means for different gum concentrations; # p < 0.05 vs. X:K ratio of 1:1, * p < 0.05 vs. X:K ratio of 2:1. Full article ">Figure 2
Mechanical properties of gum/callus hydrogels based on a 1.0% aqueous mixture of xanthan and konjac gums in different ratios (1:1, 2:1, and 3:1) and 0.1 g/mL carrot callus cells (a). Cell-free gum hydrogels were used as controls (b). Hardness and elasticity are expressed in units of H and mm, respectively. The data are presented as the mean ± S.D., n = 8. # p < 0.05 vs. X:K ratio of 1:1, * p < 0.05 vs. X:K ratio of 2:1, ** p < 0.05 vs. corresponding experimental characteristics in (a). Full article ">Figure 3
Digital images of cell-free gum hydrogels (X2K1-J) (a) and gum/callus hydrogels based on carrot juice, a 1.0% mixture of xanthan and konjac gums in a 2:1 ratio, and carrot callus cells (0.2 g/mL) (X2K1-0.2DC-J) (b). Full article ">Figure 4
The effect of carrot callus cell concentration (0.1 and 0.2 g/mL) on the mechanical properties of hydrogels based on carrot juice and a 1.0% mixture of xanthan and konjac gums in a 2:1 ratio. Hardness and elasticity are expressed in units of N and mm, respectively. The data are presented as the mean ± S.D., n = 40. Different lowercase letters (a, b, and c) indicate significant differences (p < 0.05) between the means for different callus cell concentrations. Cell-free gum hydrogels (X2K1-J) were used as controls. Full article ">Figure 5
Mechanical properties of hydrogels based on a 1.0% mixture of xanthan and konjac gums in a 1:2 ratio, 0.2 g/mL carrot callus cells, and carrot juice. Hardness and elasticity are expressed in units of H and mm, respectively. The data are presented as the mean ± S.D., n = 12. Different lowercase letters (a and b) indicate significant differences (p < 0.05) between the means. # p < 0.05 vs. X2K1-J (X:K ratio of 2:1) in <a href="#gels-10-00771-f004" class="html-fig">Figure 4</a>, * p < 0.05 vs. X2K1-0.2DC-J (X:K ratio of 2:1) in <a href="#gels-10-00771-f004" class="html-fig">Figure 4</a>. Cell-free gum hydrogels (X1K2-J) were used as controls. Full article ">Figure 6
Rheological properties of hydrogels based on 0.1 and 0.2 g/mL carrot callus cells, carrot juice, and a 1.0% mixture of xanthan and konjac gums in a 2:1 (a,c) and 1:2 (b,d) ratio. Storage modulus (G′, filled symbols) and loss modulus (G″, empty symbols) are represented as a function of shear strain (a,b) or frequency (c,d). Cell-free gum hydrogels (X2K1-J, X1K2-J) were used as controls. Full article ">Figure 7
Complex viscosity as a function of frequency of hydrogels based on 0.1 and 0.2 g/mL carrot callus cells, carrot juice, and a 1.0% mixture of xanthan and konjac gums in a 2:1 (a) and 1:2 (b) ratio. Cell-free gum hydrogels (X2K1-J, X1K2-J) were used as controls. Full article ">

20 pages, 1987 KiB

Open AccessArticle

3D Printed Bigel: A Novel Delivery System for Cannabidiol-Rich Hemp Extract

by Anna Gościniak, Filip Kocaj, Anna Stasiłowicz-Krzemień, Marcin Szymański, Tomasz M. Karpiński and Judyta Cielecka-Piontek

Gels 2024, 10(12), 770; https://doi.org/10.3390/gels10120770 - 26 Nov 2024

Viewed by 466

Abstract

The therapeutic potential of Cannabis sativa L. extract has gained significant attention due to its diverse medical applications. Sublingual administration remains a common delivery method of cannabinoids; however, challenges often arise due to the inconvenient form of the extract and its taste. To [...] Read more.

The therapeutic potential of Cannabis sativa L. extract has gained significant attention due to its diverse medical applications. Sublingual administration remains a common delivery method of cannabinoids; however, challenges often arise due to the inconvenient form of the extract and its taste. To address these issues, a novel bigel formulation was developed, combining water and oil phases to enhance stability and bioavailability. This formulation incorporates a cannabidiol-rich hemp extract, hyaluronic acid for its moisturizing properties, and a taste-masking agent to improve patient compliance and comfort. Using a standardized hemp extract rich in cannabinoids and a well-characterized terpene profile, the printability of the bigels was evaluated through 3D printing technology. A printout with known cannabidiol (CBD) and cannabidiolic acid (CBDA) content of 11.613 mg ± 0.192 of CBD and 4.732 mg ± 0.280 of CBDA in the printout was obtained. In addition, the release profile of CBD and CBDA was evaluated to determine the delivery efficiency of the active ingredient—dissolved active ingredient levels ranged from 74.84% ± 0.50 to 80.87% ± 3.20 for CBD and from 80.84 ± 1.33 to 98.31 ± 1.70 for CBDA depending on the formulation. Rheological studies were conducted to evaluate the viscosity of the bigels under varying temperature conditions, ensuring their stability and usability. Findings suggest that this 3D-printed bigel formulation could significantly enhance the delivery of cannabis extracts, offering a more convenient and effective therapeutic option for patients. This research underscores the importance of innovation in cannabinoid therapies and paves the way for further advancements in personalized medicine. Full article

(This article belongs to the Special Issue Hydrogel for Sustained Delivery of Therapeutic Agents (2nd Edition))

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14 pages, 9261 KiB

Open AccessArticle

Stretchable and Shape-Transformable Organohydrogel with Gallium Mesh Frame

by Mincheol Lee, Youngjin Choi, Young Min Bae, Seonghyeon Nam and Kiyoung Shin

Gels 2024, 10(12), 769; https://doi.org/10.3390/gels10120769 - 26 Nov 2024

Viewed by 264

Abstract

Shape-memory materials are widely utilized in biomedical devices and tissue engineering, particularly for their ability to undergo predefined shape changes in response to external stimuli. In this study, a shape-transformable organohydrogel was developed by incorporating a gallium mesh into a polyacrylamide/alginate/glycerol matrix. The [...] Read more.

Shape-memory materials are widely utilized in biomedical devices and tissue engineering, particularly for their ability to undergo predefined shape changes in response to external stimuli. In this study, a shape-transformable organohydrogel was developed by incorporating a gallium mesh into a polyacrylamide/alginate/glycerol matrix. The gallium mesh, which transitions between solid and liquid states at moderate temperatures (~29.8 °C), enhanced the hydrogel’s mechanical properties and enabled shape-memory functionality. The composite organohydrogel exhibited a high elastic modulus of ~900 kPa in the solid gallium state and ~30 kPa in the liquid gallium state, enabling reversible deformation and structural stability. Glycerol improved the hydrogel’s moisture retention, maintaining stretchability and repeated heating and cooling cycles. After multiple cycles of the shape-changing process, the organohydrogel retained its mechanical integrity, achieving shape-fixation and recovery ratios of ~96% and 95%, respectively. This combination of shape-memory functionality, stretchability, and mechanical stability makes this organohydrogel highly suitable for applications in flexible electronics, soft robotics, and biomedical devices, where adaptability and shape retention are essential. Full article

(This article belongs to the Section Gel Processing and Engineering)

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37 pages, 9715 KiB

Open AccessReview

Molecular Design and Nanoarchitectonics of Inorganic–Organic Hybrid Sol–Gel Systems for Antifouling Coatings

by Markus Bös, Ludwig Gabler, Willi Max Leopold, Max Steudel, Mareike Weigel and Konstantin Kraushaar

Gels 2024, 10(12), 768; https://doi.org/10.3390/gels10120768 - 25 Nov 2024

Viewed by 364

Abstract

Environmental protection, especially fouling protection, is a very topical and wide-ranging issue. This review explores the development, molecular design, and nanoarchitectonics of sol–gel-based hybrid coatings for antifouling applications. These coatings combine inorganic and organic materials, offering enhanced stability and adaptability, making them ideal [...] Read more.

Environmental protection, especially fouling protection, is a very topical and wide-ranging issue. This review explores the development, molecular design, and nanoarchitectonics of sol–gel-based hybrid coatings for antifouling applications. These coatings combine inorganic and organic materials, offering enhanced stability and adaptability, making them ideal for protecting surfaces from fouling. This review covers key antifouling strategies from the past decade, including biocidal additives, fouling resistance, release mechanisms, and surface topological modifications. The sol–gel hybrid systems prevent biofilm formation and organism attachment by leveraging molecular interactions, making them particularly useful in marine environments. Additionally, the study emphasizes the coatings’ environmental benefits, as they offer a potential alternative to traditional toxic antifouling methods. Overall, this research underscores the importance of sol–gel technologies in advancing eco-friendly antifouling solutions. Full article

(This article belongs to the Special Issue Gel Formation and Processing Technologies for Material Applications)

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16 pages, 3002 KiB

Open AccessArticle

In Vitro Characterization of Human Cell Sources in Collagen Type I Gel Scaffold for Meniscus Tissue Engineering

by Barbara Canciani, Nicolò Rossi, Elena Arrigoni, Riccardo Giorgino, Mirko Sergio, Lucia Aidos, Mauro Di Giancamillo, Valentina Rafaela Herrera Millar, Giuseppe M. Peretti, Alessia Di Giancamillo and Laura Mangiavini

Gels 2024, 10(12), 767; https://doi.org/10.3390/gels10120767 - 25 Nov 2024

Viewed by 322

Abstract

Strategies to repair the meniscus have achieved limited success; thus, a cell-based therapy combined with an appropriate biocompatible scaffold could be an interesting alternative to overcome this issue. The aim of this project is to analyze different cell populations and a collagen gel [...] Read more.

Strategies to repair the meniscus have achieved limited success; thus, a cell-based therapy combined with an appropriate biocompatible scaffold could be an interesting alternative to overcome this issue. The aim of this project is to analyze different cell populations and a collagen gel scaffold as a potential source for meniscus tissue engineering applications. Dermal fibroblasts (DFs) and mesenchymal stem cells (MSCs) isolated from adipose tissue (ASCs) or bone marrow (BMSCs) were analyzed. Two different fibro-chondrogenic media, M1 and M2, were tested, and qualitative and quantitative analyses were performed. Significant increases in glycosaminoglycans (GAGs) production and in fibro-cartilaginous marker expression were observed in MSCs in the presence of M1 medium. In addition, both ASCs and BMSCs cultured in M1 medium were used in association with the collagen hydrogel (MSCs-SCF) for the development of an in vitro meniscal-like tissue. Significant up-regulation in GAGs production and in the expression of aggrecan, collagen type I, and collagen type II was observed in BMSCs-SCF. This study improves knowledge of the potential of combining undifferentiated MSCs with a collagen gel as a new tissue engineering strategy for meniscus repair. Full article

(This article belongs to the Special Issue Recent Research on Medical Hydrogels)

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(A): Microscopic images showing the fusiform morphology of the three cell populations (MSCs, ASCs, and DFs) cultured under standard conditions. (B): Graph illustrating the doubling time (DT) of the three cell populations in culture, showing that ASCs and DFs have a lower DT compared to BMSCs. (C): Graph representing the total number of cells obtained after one month of culture for each cell population. ASCs and DFs show higher proliferation compared to BMSCs. (D): Graph showing the clonogenic capacity (CFU-F) of the three cell populations. Each cell population maintained good clonogenic capacity. Scalebar: 20 µm. Full article ">Figure 2
(A): Graph showing the induction of lipid vacuoles in MSCs after 14 days of insulin treatment. ASCs and BMSCs showed a significant increase in lipid production, while DFs showed no induction. (B) (Upper Panel): Graph representing alkaline phosphatase (ALP) activity in MSCs and DFs induced toward the osteogenic lineage. A significant increase in ALP activity was observed in ASCs and BMSCs compared to DFs. (B) (Middle Panel): Graph showing collagen production in osteo-induced cells, with significant increases in all cell populations. (B) (Lower Panel): Graph representing calcium deposition in osteo-induced cells, showing a significant increase for ASCs, BMSCs, and DFs compared to controls. **: p < 0.01; ***: p < 0.001. Full article ">Figure 3
(A): Graph showing GAG production in MSCs and DFs cultured in pellet and treated with M1 and M2 media. A significant increase in GAGs is observed in the presence of M1 medium for ASCs and BMSCs. (B): Histological image showing Safranin O staining in ASCs, BMSCs, and DFs pellets treated with SFM, M1, and M2 medium. Scalebar: 200 µm. **: p < 0.01; ***: p < 0.001. Full article ">Figure 4
(A–C): Graphs showing gene expression of Aggrecan, Collagen type I, and Collagen type II in cell populations treated with SFM, M1, and M2 medium. *: p < 0.01; ***: p < 0.001. Full article ">Figure 5
(A) (Left Panel): Graph illustrating GAG production in differentiated ASCs-SCF, with no significant increases compared to controls (SFM). (A) (Right Panel): Graph showing the increase in GAG production in differentiated BMSCs-SCF in the presence of M1 medium for 7, 14, and 21 days, compared to controls (SFM). (B): Histological images showing Safranin O staining in constructs generated with ASCs and BMSCs. The image highlights extracellular matrix accumulation and a more compact structure in the differentiated constructs, compared to SFM controls. Scalebar: 200 µm. *: p < 0.05; **: p < 0.01. Full article ">Figure 6
(A): Graph representing the upregulation of Aggrecan expression in differentiated MSCs (ASCs and BMSCs) in the presence of M1 medium, with an increase over time. (B,C) (Left Panel): Graphs showing Collagen type I and II expression in ASCs, with no induction for Collagen type I and a different trend for Collagen type II. (B,C) (Right Panel): Graphs showing Collagen type I and II expression in BMSCs in the presence of M1 medium, with a significant increase compared to controls. *: p < 0.05; ***: p < 0.001. Full article ">Figure 7
Graphs showing the effect of the collagen sponge on undifferentiated cell populations (SFM ASCs- and BMSCs-SCF). All markers evaluated for fibro-chondrogenic differentiation show a significant increase in SFM bioconstructs maintained for 7, 14, and 21 days compared to day 0, suggesting the inductive potential of the collagen sponge on MSCs. §: p < 0.05; §§: p < 0.01. Full article ">

19 pages, 3572 KiB

Open AccessArticle

The Effect of Cellulose Nanocrystals on the Molecular Organization, Thermomechanical, and Shape Memory Properties of Gelatin-Matrix Composite Films

by Cristina Padilla, Marzena Pępczyńska, Cristian Vizueta, Franck Quero, Paulo Díaz-Calderón, William Macnaughtan, Tim Foster and Javier Enrione

Gels 2024, 10(12), 766; https://doi.org/10.3390/gels10120766 - 25 Nov 2024

Viewed by 371

Abstract

Gelatin is a natural hydrocolloid with excellent film-forming properties, high processability, and tremendous potential in the field of edible coatings and food packaging. However, its reinforcing by materials such as cellulose nanocrystals (CNC) is often necessary to improve its mechanical behavior, including shape [...] Read more.

Gelatin is a natural hydrocolloid with excellent film-forming properties, high processability, and tremendous potential in the field of edible coatings and food packaging. However, its reinforcing by materials such as cellulose nanocrystals (CNC) is often necessary to improve its mechanical behavior, including shape memory properties. Since the interaction between these polymers is complex and its mechanism still remains unclear, this work aimed to study the effect of low concentrations of CNC (2, 6, and 10 weight%) on the molecular organization, thermomechanical, and shape memory properties in mammalian gelatin-based composite films at low moisture content (~10 weight% dry base). The results showed that the presence of CNCs (with type I and type II crystals) interfered with the formation of the gelatin triple helix, with a decrease from 21.7% crystallinity to 12% in samples with 10% CNC but increasing the overall crystallinity (from 21.7% to 22.6% in samples with 10% CNC), which produced a decrease in the water monolayer in the composites. These changes in crystallinity also impacted significantly their mechanical properties, with higher E’ values (from 1 × 10⁴ to 1.3 × 10⁴ Pa at 20 °C) and improved thermal stability at higher CNC content. Additionally, the evaluation of their shape memory properties indicated that while molecular interactions between the two components occur, CNCs negatively impacted the magnitude and kinetics of the shape recovery of the composites (more particularly at 10 weight% CNC, reducing shape recovery from 90% to 70%) by reducing the netting point associated with the lower crystallinity of the gelatin. We believe that our results contribute in elucidating the interactions of gelatin–CNC composites at various structural levels and highlights that even though CNC acts as a reinforcement material on gelatin matrices, their interaction are complex and do not imply synergism in their properties. Further investigation is, however, needed to understand CNC–gelatin interfacial interactions with the aim of modulating their interactions depending on their desired application. Full article

(This article belongs to the Special Issue Design and Development of Gelatin-Based Materials)

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21 pages, 10455 KiB

Open AccessArticle

Experimental Evaluation of a Recrosslinkable CO₂-Resistant Micro-Sized Preformed Particle Gel for CO₂ Sweep Efficiency Improvement in Reservoirs with Super-K Channels

by Adel Alotibi, Tao Song, Ali Al Brahim, Baojun Bai and Thomas Schuman

Gels 2024, 10(12), 765; https://doi.org/10.3390/gels10120765 - 24 Nov 2024

Viewed by 248

Abstract

A recrosslinkable CO₂-resistant branched preformed particle gel (CO₂-BRPPG) was developed for controlling CO₂ injection conformance, particularly in reservoirs with super-permeable channels. Previous work focused on a millimeter-sized CO₂-BRPPG in open fractures, but its performance in high-permeability [...] Read more.

A recrosslinkable CO₂-resistant branched preformed particle gel (CO₂-BRPPG) was developed for controlling CO₂ injection conformance, particularly in reservoirs with super-permeable channels. Previous work focused on a millimeter-sized CO₂-BRPPG in open fractures, but its performance in high-permeability channels with pore throat networks remained unexplored. This study used a sandpack model to evaluate a micro-sized CO₂-BRPPG under varying conditions of salinity, gel concentration, and pH. At ambient conditions, the equilibrium swelling ratio (ESR) of the gel reached 76 times its original size. This ratio decreased with increasing salinity but remained stable at low pH values, demonstrating the gel’s resilience in acidic environments. Rheological tests revealed shear-thinning behavior, with gel strength improving as salinity increased (the storage modulus rose from 113 Pa in 1% NaCl to 145 Pa in 10% NaCl). Injectivity tests showed that lower gel concentrations reduced the injection pressure, offering flexibility in deep injection treatments. Gels with higher swelling ratios had lower injection pressures due to increased strength and reduced deformability. The gel maintained stable plugging performance during two water-alternating-CO₂ cycles, but a decline was observed in the third cycle. It also demonstrated a high CO₂ breakthrough pressure of 177 psi in high salinity conditions (10% NaCl). The permeability reduction for water and CO₂ was influenced by gel concentration and salinity, with higher salinity increasing the permeability reduction and higher gel concentrations decreasing it. These findings underscore the effectiveness of the CO₂-BRPPG in improving CO₂ sweep efficiency and managing CO₂ sequestration in reservoirs with high permeability. Full article

(This article belongs to the Special Issue Advances in Polymeric Gels and Applications for Hydrocarbon Development and Geologic Carbon Storage)

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15 pages, 4134 KiB

Open AccessArticle

Enhanced Ammonia Capture for Adsorption Heat Pumps Using a Salt-Embedded COF Aerogel Composite

by Hiluf T. Fissaha and Duckjong Kim

Gels 2024, 10(12), 764; https://doi.org/10.3390/gels10120764 - 24 Nov 2024

Viewed by 313

Abstract

Adsorption heat pumps (AHPs) have garnered significant attention due to their efficient use of low-grade thermal energy, eco-friendly nature, and cost-effectiveness. However, a significant challenge lies in developing adsorbent materials that can achieve a high uptake capacity, rapid adsorption rates, and efficient reversible [...] Read more.

Adsorption heat pumps (AHPs) have garnered significant attention due to their efficient use of low-grade thermal energy, eco-friendly nature, and cost-effectiveness. However, a significant challenge lies in developing adsorbent materials that can achieve a high uptake capacity, rapid adsorption rates, and efficient reversible release of refrigerants, such as ammonia (NH₃). Herein, we developed and synthesized a novel salt-embedded covalent organic framework (COF) composite material designed for enhanced NH₃ capture. This material was prepared by encapsulating sodium bromide (NaBr) within a porous and densely functionalized sulfonic acid-based COF. The COF was synthesized through a Schiff base (imine) condensation reaction, providing a robust platform for effective NaBr impregnation. The COF-based aerogel composite powder was investigated for its potential in ammonia-based AHPs, benefiting from both the porous, highly functionalized COF structure and the strong NH₃ affinity of the impregnated NaBr. The composite adsorbent demonstrates an impressive NH₃ adsorption capacity, adsorption rate, and stability. The exceptional NH₃ adsorption performance of the COF-based aerogel composite powder is primarily attributed to the uniformly dispersed NaBr within the COF, the coordination of NH₃ molecules with Na⁺ ions, and the hydrogen bonding interaction between NH₃ and Br- ions. These findings highlight the potential of the salt-embedded COF composite for use in NH₃-based AHPs, gas separation, and other related applications. Full article

(This article belongs to the Special Issue Recent Progress and Development of Advanced Aerogels: Latest Processing Methods, Improved Properties and Application (2nd Edition))

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12 pages, 1837 KiB

Open AccessArticle

Modifying the Resistant Starch Content and the Retrogradation Characteristics of Potato Starch Through High-Dose Gamma Irradiation

by Zhangchi Peng, Xuwei Wang, Zhijie Liu, Liang Zhang, Linrun Cheng, Jiahao Nia, Youming Zuo, Xiaoli Shu and Dianxing Wu

Gels 2024, 10(12), 763; https://doi.org/10.3390/gels10120763 - 24 Nov 2024

Viewed by 368

Abstract

Potato starch is widely utilized in the food industry. Gamma irradiation is a cost-effective and environmentally friendly method for starch modification. Nevertheless, there is a scarcity of comprehensive and consistent knowledge regarding the physicochemical characteristics of high-dose gamma-irradiated potato starch, retrogradation properties in [...] Read more.

Potato starch is widely utilized in the food industry. Gamma irradiation is a cost-effective and environmentally friendly method for starch modification. Nevertheless, there is a scarcity of comprehensive and consistent knowledge regarding the physicochemical characteristics of high-dose gamma-irradiated potato starch, retrogradation properties in particular. In this study, potato starch was exposed to gamma rays at doses of 0, 30, 60, 90, and 120 kGy. Various physicochemical properties, including retrogradation characteristics, were investigated. Generally, the apparent amylose content (AAC), water absorption, gel viscosity, gel hardness, and gumminess decreased as the doses of gamma irradiation increased. Conversely, the resistant starch (RS), amylose content evaluated by the concanavalin A precipitation method, water solubility, and enthalpy of gelatinization were increased. Additionally, swelling power, crystalline structure, and amylopectin branch chain length distribution either remained stable or exhibited only minor changes. Notably, the degree of retrogradation of potato starches on day 7 was positively correlated with the doses of gamma irradiation. Full article

(This article belongs to the Special Issue Natural Bioactive Compounds and Gels)

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30 pages, 3826 KiB

Open AccessReview

Exosome-Integrated Hydrogels for Bone Tissue Engineering

by Hee Sook Hwang and Chung-Sung Lee

Gels 2024, 10(12), 762; https://doi.org/10.3390/gels10120762 - 23 Nov 2024

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Abstract

Exosome-integrated hydrogels represent a promising frontier in bone tissue engineering, leveraging the unique biological properties of exosomes to enhance the regenerative capabilities of hydrogels. Exosomes, as naturally occurring extracellular vesicles, carry a diverse array of bioactive molecules that play critical roles in intercellular [...] Read more.

Exosome-integrated hydrogels represent a promising frontier in bone tissue engineering, leveraging the unique biological properties of exosomes to enhance the regenerative capabilities of hydrogels. Exosomes, as naturally occurring extracellular vesicles, carry a diverse array of bioactive molecules that play critical roles in intercellular communication and tissue regeneration. When combined with hydrogels, these exosomes can be spatiotemporally delivered to target sites, offering a controlled and sustained release of therapeutic agents. This review aims to provide a comprehensive overview of the recent advancements in the development, engineering, and application of exosome-integrated hydrogels for bone tissue engineering, highlighting their potential to overcome current challenges in tissue regeneration. Furthermore, the review explores the mechanistic pathways by which exosomes embedded within hydrogels facilitate bone repair, encompassing the regulation of inflammatory pathways, enhancement of angiogenic processes, and induction of osteogenic differentiation. Finally, the review addresses the existing challenges, such as scalability, reproducibility, and regulatory considerations, while also suggesting future directions for research in this rapidly evolving field. Thus, we hope this review contributes to advancing the development of next-generation biomaterials that synergistically integrate exosome and hydrogel technologies, thereby enhancing the efficacy of bone tissue regeneration. Full article

(This article belongs to the Special Issue Recent Advances in Hydrogels for Biomedical Application (2nd Edition))

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Exosome-integrated hydrogels for bone tissue engineering. Exosomes, which develop from the endosomal system within cells, are packed with proteins, lipids, and nucleic acids that facilitate robust intercellular communication. Exosomes, typically around 40–100 nm in size, belong to a diverse group of extracellular vesicles, set apart by their phospholipid membrane and specific formation pathway. They are released by a variety of cell types and circulate in bodily fluids, with their molecular composition reflecting the origin and condition of the parent cell. Exosomes can be isolated and fabricated through differential centrifugation, density gradient centrifugation, ultrafiltration, size exclusion chromatography, affinity nanoparticle-based isolation, polymer precipitation, microfluidic technologies, etc. Exosomes contain diverse bioactive molecules such as proteins, nucleic acids, and lipids, with two main types of proteins: general markers (like CD9, CD63, and CD81) and proteins unique to their parent cell. Exosomes can be modified with drug loading, active targeting, and stimuli-responsiveness. Hydrogels have become valuable tools in biomedical applications for exosome delivery. Hydrogels, as water-retentive polymer networks, encapsulate exosomes, improving their retention at target sites and providing controlled release to enhance localized effects. These exosome–hydrogel composites show promise in areas such as bone tissue engineering and treatment. (Created with <a href="https://biorender.com" target="_blank">https://biorender.com</a>). Full article ">Figure 2
Human umbilical cord mesenchymal stem cell-derived exosomes with hydroxyapatite-embedded hyaluronic acid-alginate hydrogel for bone regeneration. (A) Schematic illustration of human umbilical cord mesenchymal stem cell-derived exosomes with hydroxyapatite-embedded hyaluronic acid-alginate hydrogel. (B) Transmission electron microscopy image of exosomes. (C) Size distribution of exosomes. (D) Western blot analysis of the exosome surface markers. (E) Release profiles of exosomes from the hydrogels with or without hydroxyapatite. * p < 0.05 compared to the control group; # p < 0.05 compared to the hydrogel group. (F) Confocal microscopy images of hydrogel with or without red fluorescence DiI-labeled exosomes. (G) Reconstructed 3D micro-CT images of the exosome-integrated hydrogels. Red circles indicate the defect area. (H) Quantitative analysis of bone regeneration using bone volume/tissue volume (BV/TV). Reproduced with permission from Yang et al. [<a href="#B164-gels-10-00762" class="html-bibr">164</a>]. Full article ">Figure 3
Exosome (Exo)-encapsulated stem cell-recruitment hydrogel microcarriers for osteoarthritis (OA) treatment. (A) Schematic illustration of Exo-encapsulated stem cell recruitment particles for OA treatment. (a) Hyaluronic acid (HA) and gelatin-based polymer matrix and bioactive components of hydrogel microcarriers. (b) Fabrication process of hydrogel microcarriers. (c) Application of microcarriers for OA treatment. (B–D) Characterization of particles and Exo. (B) Microscopic image of the particles. (C) The enlarged view of (B). (D) The size distribution of the particles. (E,F) H&E and Safranin O-fast green staining results. (E) H&E results after different particle treatments. (F) Safranin O-fast green staining results after the particle treatment. Par = microfluidic electrospray-generated hydrogel particles; Par@Pep = Par modified by SKPPGTSS peptides; Par@Exo = Par loaded with Exo; Par@Pep&Exo = Par@Pep loaded with Exo. Reproduced with permission from Yang et al. [<a href="#B173-gels-10-00762" class="html-bibr">173</a>]. Full article ">

20 pages, 4539 KiB

Open AccessArticle

Development of Soft Wrinkled Micropatterns on the Surface of 3D-Printed Hydrogel-Based Scaffolds via High-Resolution Digital Light Processing

by Mauricio A. Sarabia-Vallejos, Scarleth Romero De la Fuente, Nicolás A. Cohn-Inostroza, Claudio A. Terraza, Juan Rodríguez-Hernández and Carmen M. González-Henríquez

Gels 2024, 10(12), 761; https://doi.org/10.3390/gels10120761 - 23 Nov 2024

Viewed by 220

Abstract

The preparation of sophisticated hierarchically structured and cytocompatible hydrogel scaffolds is presented. For this purpose, a photosensitive resin was developed, printability was evaluated, and the optimal conditions for 3D printing were investigated. The design and fabrication by additive manufacturing of tailor-made porous scaffolds [...] Read more.

The preparation of sophisticated hierarchically structured and cytocompatible hydrogel scaffolds is presented. For this purpose, a photosensitive resin was developed, printability was evaluated, and the optimal conditions for 3D printing were investigated. The design and fabrication by additive manufacturing of tailor-made porous scaffolds were combined with the formation of surface wrinkled micropatterns. This enabled the combination of micrometer-sized channels (100–200 microns) with microstructured wrinkled surfaces (1–3 μm wavelength). The internal pore structure was found to play a critical role in the mechanical properties. More precisely, the TPMS structure with a zero local curvature appears to be an excellent candidate for maintaining its mechanical resistance to compression stress, thus retaining its structural integrity upon large uniaxial deformations up to 70%. Finally, the washing conditions selected enabled us to produce noncytotoxic materials, as evidenced by experiments using AlamarBlue to follow the metabolic activity of the cells. Full article

(This article belongs to the Special Issue Advanced Soft Gels with Enhanced Functionality for Biomedical and Additive Manufacturing Applications)

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15 pages, 4814 KiB

Open AccessArticle

Development of Variable Charge Cationic Hydrogel Particles with Potential Application in the Removal of Amoxicillin and Sulfamethoxazole from Water

by Francisca L. Aranda, Manuel F. Meléndrez, Mónica A. Pérez, Bernabé L. Rivas, Eduardo D. Pereira and Daniel A. Palacio

Gels 2024, 10(12), 760; https://doi.org/10.3390/gels10120760 - 23 Nov 2024

Viewed by 215

Abstract

Cationic hydrogel particles (CHPs) crosslinked with glutaraldehyde were synthesized and characterized to evaluate their removal capacity for two globally consumed antibiotics: amoxicillin and sulfamethoxazole. The obtained material was characterized by FTIR, SEM, and TGA, confirming effective crosslinking. The optimal working pH was determined [...] Read more.

Cationic hydrogel particles (CHPs) crosslinked with glutaraldehyde were synthesized and characterized to evaluate their removal capacity for two globally consumed antibiotics: amoxicillin and sulfamethoxazole. The obtained material was characterized by FTIR, SEM, and TGA, confirming effective crosslinking. The optimal working pH was determined to be 6.0 for amoxicillin and 4.0 for sulfamethoxazole. Under these conditions, the CHPs achieved over 90.0% removal of amoxicillin after 360 min at room temperature, while sulfamethoxazole removal reached approximately 60.0% after 300 min. Thermodynamic analysis indicated that adsorption occurs through a physisorption process and is endothermic. The ΔH° values of 28.38 kJ mol⁻¹, 12.39 kJ mol⁻¹, and ΔS° 97.19 J mol⁻¹ K⁻¹, and 33.94 J mol⁻¹ K⁻¹ for AMX and SMX, respectively. These results highlight the potential of CHPs as promising materials for the removal of such contaminants from aqueous media. Full article

(This article belongs to the Special Issue Designing Hydrogels and Hydrogel-Derived Materials for Agriculture and Water Sustainability)

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17 pages, 11736 KiB

Open AccessArticle

3D Printing of New Foods Using Cellulose-Based Gels Obtained from Cerotonia siliqua L. Byproducts

by Antoni Capellà, Mónica Umaña, Esperanza Dalmau, Juan A. Cárcel and Antoni Femenia

Gels 2024, 10(12), 759; https://doi.org/10.3390/gels10120759 (registering DOI) - 23 Nov 2024

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Abstract

Carob pulp is a valuable source of cellulose-rich fraction (CRF) for many food applications. This study aimed to obtain and characterize a CRF derived from carob pulp waste after sugar removal and to evaluate its potential use in the 3D printing of cellulose-rich [...] Read more.

Carob pulp is a valuable source of cellulose-rich fraction (CRF) for many food applications. This study aimed to obtain and characterize a CRF derived from carob pulp waste after sugar removal and to evaluate its potential use in the 3D printing of cellulose-rich foods. Thus, the extraction of the CRF present in carob pulp (by obtaining the alcohol-insoluble residue) was carried out, accounting for nearly 45% dm (dry matter) of this byproduct. The CRF contained about 24% dm of cellulose. The functional properties (swelling capacity, water retention, and fat adsorption) related to this fraction were determined, showing a value of 5.9 mL/g of CRF and 4.0 and 6.5 g/g of CRF, respectively. Different gels were formulated with a total solids content of 15% wm (wet matter), using potato peel flour as a base and partially substituting with CRF (0% to 8% wm). The cellulose-based gels were characterized in terms of viscosity, water distribution (low-field Nuclear Magnetic Resonance), and printability, while the 3D printed samples were assessed for their textural properties. As the percentage of added CRF increased, the viscosity decreased while the water retention increased. Printability improved when small proportions of CRF (2% to 4%) were used, while it deteriorated for higher percentages (6% to 8%). The textural properties (hardness, adhesiveness, cohesiveness, and gumminess) showed significant changes caused by the addition of CRF, with gels containing 3% to 4% CRF exhibiting the most suitable printing values. In summary, this study demonstrates the significant potential of carob cellulose-based gel as an ingredient in the 3D printing of novel fiber-rich foods, contributing to reducing food waste and promoting sustainable practices within the framework of the circular economy. Full article

(This article belongs to the Special Issue Cellulose-Based Gels: Synthesis, Properties, and Applications)

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17 pages, 7663 KiB

Open AccessArticle

Preparation and Characterization of Poly(acrylic acid-co-vinyl imidazole) Hydrogel-Supported Palladium Catalyst for Tsuji–Trost and Suzuki Reactions in Aqueous Media

by Huijun Song, Amatjan Sawut, Rena Simayi and Yuqi Sun

Gels 2024, 10(12), 758; https://doi.org/10.3390/gels10120758 - 23 Nov 2024

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Abstract

In this study, a novel polyacrylate-co-vinyl imidazole hydrogel-supported palladium (Pd) catalyst (P(AA-co-VI)@Pd) was prepared through heat-initiated polymerization, starting with the formation of a complex between vinyl imidazole and palladium chloride, followed by the addition of 75% neutralized acrylic acid (AA), crosslinking agent, and [...] Read more.

In this study, a novel polyacrylate-co-vinyl imidazole hydrogel-supported palladium (Pd) catalyst (P(AA-co-VI)@Pd) was prepared through heat-initiated polymerization, starting with the formation of a complex between vinyl imidazole and palladium chloride, followed by the addition of 75% neutralized acrylic acid (AA), crosslinking agent, and initiator. The structure and morphology of the catalyst were characterized using ICP-OES, SEM, EDX, Mapping, FT-IR, TGA, XRD, XPS and TEM techniques. It was confirmed that the catalyst exhibited excellent compatibility with water solvent and uniform distribution of Pd. The P(AA-co-VI)@Pd hydrogel catalyst demonstrated remarkable catalytic activity and ease of separation. Notably, in a Tsuji–Trost reaction, employing water as the solvent, it achieved a conversion rate as high as 94% at very low catalyst dosages, indicating its superior catalytic performance. Moreover, after six consecutive cycles, the catalyst maintained good activity and structural stability, highlighting its exceptional reusability and environmental friendliness. Furthermore, the outstanding efficiency of the catalyst was also observed in a Suzuki coupling reaction where both conversion rate and yield reached 100% and 99%, respectively, within just one hour reaction time, thus further validating its universality and efficacy across various chemical reactions. Full article

(This article belongs to the Special Issue Gel-Based Materials: Preparations and Characterization (2nd Edition))

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15 pages, 3295 KiB

Open AccessArticle

Electrostatic Gelatin Nanoparticles for Biotherapeutic Delivery

by Connor Tobo, Avantika Jain, Madhushika Elabada Gamage, Paul Jelliss and Koyal Garg

Gels 2024, 10(12), 757; https://doi.org/10.3390/gels10120757 - 23 Nov 2024

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Abstract

Biological agents such as extracellular vesicles (EVs) and growth factors, when administered in vivo, often face rapid clearance, limiting their therapeutic potential. To address this challenge and enhance their efficacy, we propose the electrostatic conjugation and sequestration of these agents into gelatin-based biomaterials. [...] Read more.

Biological agents such as extracellular vesicles (EVs) and growth factors, when administered in vivo, often face rapid clearance, limiting their therapeutic potential. To address this challenge and enhance their efficacy, we propose the electrostatic conjugation and sequestration of these agents into gelatin-based biomaterials. In this study, gelatin nanoparticles (GNPs) were synthesized via the nanoprecipitation method, with adjustments to the pH of the gelatin solution (4.0 or 10.0) to introduce either a positive or negative charge to the nanoparticles. The GNPs were characterized using dynamic light scattering (DLS), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), and Transmission electron microscopy (TEM) imaging. Both positively and negatively charged GNPs were confirmed to be endotoxin-free and non-cytotoxic. Mesenchymal stem cell (MSC)-derived EVs exhibited characteristic surface markers and a notable negative charge. Zeta potential measurements validated the electrostatic conjugation of MSC-EVs with positively charged GNPs. Utilizing a transwell culture system, we evaluated the impact of EV-GNP conjugates encapsulated within a gelatin hydrogel on macrophage secretory activity. The results demonstrated the bioactivity of EV-GNP conjugates and their synergistic effect on macrophage secretome over five days of culture. In summary, these findings demonstrate the efficacy of electrostatically coupled biotherapeutics with biomaterials for tissue regeneration applications. Full article

(This article belongs to the Special Issue Hydrogel for Tissue Engineering and Biomedical Therapeutics)

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15 pages, 6312 KiB

Open AccessArticle

Environmentally Friendly Nanoporous Polymeric Gels for Sustainable Wastewater Treatment

by Tarek M. Madkour, Rasha E. Elsayed and Rasha A. Azzam

Gels 2024, 10(12), 756; https://doi.org/10.3390/gels10120756 - 22 Nov 2024

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Abstract

Environmentally friendly nanoporous gels are tailor-designed and employed in the adsorption of toxic organic pollutants in wastewater. To ensure the maximum adsorption of the contaminant molecules by the gels, molecular modeling techniques were used to evaluate the binding affinity between the toxic organic [...] Read more.

Environmentally friendly nanoporous gels are tailor-designed and employed in the adsorption of toxic organic pollutants in wastewater. To ensure the maximum adsorption of the contaminant molecules by the gels, molecular modeling techniques were used to evaluate the binding affinity between the toxic organic contaminants such as methylene blue (MB) and Congo red (CR) and various biopolymers. To generate nanopores in the matrix of the polymeric gels, salt crystals were used as porogen. The pores were then used to accommodate catalytic nickel (Ni⁰) nanoparticles. Under UV irradiation, the nanoparticles demonstrated the effective adsorption and photocatalytic degradation of both the methylene blue and Congo red dyes, achieving removal efficiencies of up to 90% for MB and 80% for CR. The thermodynamic analysis suggested a spontaneous endothermic dissociative adsorption mechanism, which implies the oxidative catalytic degradation of the dyes. The kinetic modeling suggested a pseudo-second-order model, while the model for intra-particle diffusion revealed that Congo red diffuses faster than methylene blue. MB adsorption followed a Langmuir isotherm, while CR adsorption followed a linear isotherm. The results confirm that dye molecules initially undergo physisorption and subsequent dissociative adsorption. The products of the catalytic degradation of methylene blue continue to be absorbed on the surface of the nanoparticles, while those of Congo red switch to preferential desorption. Full article

(This article belongs to the Special Issue Application of Hydrogels in Adsorption of Pollutants in Water and Wastewater Treatment)

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Full article ">Figure 1
Snapshots of the molecular simulations of (a) the polymer blend mixed with MB dye molecules and (b) the polymer blend mixed with CR dye molecules. Each cell has a triclinic lattice with a side length of 19.7064 Å and an angle of 90°. Full article ">Figure 2
Enthalpy of mixing MB (a) and CR (b) with the different polymeric blends at different dye mole fractions. Full article ">Figure 3
(a) SEM image for the unloaded gel, (b) SEM image for the Ni-loaded gel, (c) TGA for the unloaded gel, and (d) TGA for the Ni-loaded gel. Full article ">Figure 4
BET isotherms of the unloaded gel (a) and the Ni0-loaded gel (b). Full article ">Figure 5
The uptake capacity and percent removal of methylene blue and Congo red at equilibrium at various initial concentrations of the dye solutions (a), used dose of the adsorbent (b), and operating temperature (c). Full article ">Figure 6
Plots of van’t Hoff (a) and equilibrium isotherms (b) for MB and CR adsorption. Full article ">Figure 7
The kinetic plots of the removal of methylene blue and Congo red dyes (a), linear isotherms estimated using the pseudo-first-order model (b), linear isotherms estimated using the pseudo-second-order model (c), and linear isotherms estimated using the intra-particle diffusion model (d). Full article ">Scheme 1
Schematic diagram for the preparation of in situ impregnated polymeric gels. Full article ">

20 pages, 1695 KiB

Open AccessReview

Recent Advances of Cellulose-Based Hydrogels Combined with Natural Colorants in Smart Food Packaging

by Lan Yang, Qian-Yu Yuan, Ching-Wen Lou, Jia-Horng Lin and Ting-Ting Li

Gels 2024, 10(12), 755; https://doi.org/10.3390/gels10120755 - 21 Nov 2024

Viewed by 332

Abstract

Due to the frequent occurrence of food safety problems in recent years, healthy diets are gradually receiving worldwide attention. Chemical pigments are used in smart food packaging because of their bright colors and high visibility. However, due to shortcomings such as carcinogenicity, people [...] Read more.

Due to the frequent occurrence of food safety problems in recent years, healthy diets are gradually receiving worldwide attention. Chemical pigments are used in smart food packaging because of their bright colors and high visibility. However, due to shortcomings such as carcinogenicity, people are gradually looking for natural pigments to be applied in the field of smart food packaging. In traditional smart food packaging, the indicator and the packaging bag substrate have different degrees of toxicity. Smart food packaging that combines natural colorants and cellulose-based hydrogels is becoming more and more popular with consumers for being natural, non-toxic, environmentally friendly, and renewable. This paper reviews the synthesis methods and characteristics of cellulose-based hydrogels, as well as the common types and characteristics of natural pigments, and discusses the application of natural colorants and cellulose-based hydrogels in food packaging, demonstrating their great potential in smart food packaging. Full article

(This article belongs to the Special Issue Advances in Cellulose-Based Hydrogels (3rd Edition))

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25 pages, 8025 KiB

Open AccessReview

The Unfulfilled Potential of Synthetic and Biological Hydrogel Membranes in the Treatment of Abdominal Hernias

by Kenigen Manikion, Christodoulos Chrysanthou and Constantinos Voniatis

Gels 2024, 10(12), 754; https://doi.org/10.3390/gels10120754 - 21 Nov 2024

Viewed by 403

Abstract

Hydrogel membranes can offer a cutting-edge solution for abdominal hernia treatment. By combining favorable mechanical parameters, tissue integration, and the potential for targeted drug delivery, hydrogels are a promising alternative therapeutic option. The current review examines the application of hydrogel materials composed of [...] Read more.

Hydrogel membranes can offer a cutting-edge solution for abdominal hernia treatment. By combining favorable mechanical parameters, tissue integration, and the potential for targeted drug delivery, hydrogels are a promising alternative therapeutic option. The current review examines the application of hydrogel materials composed of synthetic and biological polymers, such as polyethylene glycol (PEG), polyvinyl alcohol (PVA), gelatine, and silk fibroin, in the context of hernia repair. Overall, this review highlights the current issues and prospects of hydrogel membranes as viable alternatives to the conventional hernia meshes. The emphasis is placed on the applicability of these hydrogels as components of bilayer systems and standalone materials. According to our research, hydrogel membranes exhibit several advantageous features relevant to hernia repair, such as a controlled inflammatory reaction, tissue integration, anti-adhesive-, and even thermoresponsive properties. Nevertheless, despite significant advancements in material science, the potential of hydrogel membranes seems neglected. Bilayer constructs have not transitioned to clinical trials, whereas standalone membranes seem unreliable due to the lack of comprehensive mechanical characterization and long-term in vivo experiments. Full article

(This article belongs to the Special Issue Biosoursed and Bioinspired Gels for Biomedical Applications (2nd Edition))

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Gels, Volume 10, Issue 12 (December 2024) – 25 articles

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