RU2525936C1 - Method of filtering solutions and suspensions - Google Patents

Abstract

FIELD: biotechnology.

SUBSTANCE: method comprises filtering the solutions or suspensions of microorganisms or proteins by passing through a solid elastic membrane of raw rubber or rubber. To start the filtration the system of pores is formed not exceeding the size of the concentrate, using a pulse laser radiation with the power not more than 1 J/cm². The material of the elastic membrane has the ability to self-tightening of pores after termination of the pulse laser radiation, and has a modulus of elasticity of 10-20 MPa, and the frequency of the pulse laser radiation is 1-39 kHz, the wavelength is 1064 nm, pulse duration is 10 ns.

EFFECT: increased safety of work and reduction of labour intensity.

2 cl, 1 dwg

Description

The invention can be used in technological schemes for cleaning, sterilization, concentration of solutions containing viruses, bacteria, proteins, as well as in the medical industry for the production of biological preparations.

Nuclear filters are known that are formed by irradiating polymer films with accelerated heavy ions, followed by etching of the destroyed polymer sections. Along the ion trajectory, through channels of the correct form arise. This allows the use of nuclear filters for the separation of microparticles by size, their concentration by ultrafine cleaning of liquid media, and sterilization of liquids. For the manufacture of nuclear filters are mainly used films of lavsan 6-12 microns thick and other polymeric materials that are resistant to external influences, as well as a source of heavy ions (www.dic.academic.ru).

Closest to the claimed filtration method adopted as a prototype is a method for filtering solutions or suspensions of microorganisms or proteins by passing them through a porous membrane, moreover, filtering is carried out through a material whose pore system is formed by bombardment by accelerated uniform heavy ions followed by etching of their tracks. (Aut. Certificate 520778, IPC C12K 1/10, published on July 25, 1977)

The disadvantage of this method is the high technological complexity of filtering solutions or suspensions of microorganisms or proteins, which consists in using a radioactive source of heavy ions.

The objective of the proposed method is to reduce the complexity and ensure safety when filtering solutions or suspensions of viruses due to the use for the formation of pores in the membrane of laser radiation.

The technical result is achieved due to the filtering method by passing through a porous membrane, in contrast to the prototype, filtering is carried out through a membrane of elastic material, the pore system of the membrane is formed using laser radiation, followed by self-tightening of the pores.

In addition, a membrane of butodiene rubbers or rubber with an elastic modulus of 10-20 MPa, pulsed laser radiation with a frequency of 1-39 kHz, a wavelength of 1064 nm and a pulse duration of 10 ns are used.

The method of filtering solutions, suspensions, microorganisms or proteins is that to separate the suspension, filtering occurs through a continuous elastic membrane. The pore system of the membrane is formed using pulsating laser radiation, which produces point-breaking penetration of a continuous elastic membrane in the form of cylindrical pores (channels). In this case, the filtrate (purified liquid, water) passes through the pores formed by laser radiation through the membrane, and the concentrate (microparticles, viruses), depending on size, can either form a precipitate on the membrane surface or clog the membrane pores. Filtering is carried out under the action of a pressure difference in front of and after the membrane. After turning off the laser radiation, self-tightening of the formed pores occurs due to the elastic properties of the membrane.

It is known that most rod bacteria are 0.5-1.0 μm in size, viruses are 20-300 nm in size, and rabies virus is 80-180 nm in size (www.med-books.info).

To filter liquid from rod bacteria, the pore size of the membrane should be less than 0.5-1.0 microns, from viruses the size should be less than 20-300 nm, from rabies virus should be less than 80-180 nm.

The drawing shows a functional diagram of the filtration of solutions, suspensions, viruses.

To implement the method, an apparatus is used consisting of a container 1 separated by an elastic membrane 2 with pores 5 into a compartment for filtrate 3 and a compartment for concentrate 4, lasers 6.

The suspension is located in a container separated by a continuous elastic membrane 2 into the compartment for the filtrate 3 and the compartment for the suspension and concentrate 4. Filtering is carried out under the influence of the pressure difference in front of the membrane and after it within 20-30 kPa.

The power (not shown) of the lasers 6 is turned on, pulsed laser radiation is generated, with the help of which a system of cylindrical pores is formed 5. The filtrate passes through the pores 5 formed by the laser beam through the membrane, and the concentrate (solid microparticles, viruses) remains in front of the membrane or clogs the pores . After the laser pulse is interrupted, self-tightening of the formed pores occurs due to the elastic properties of the membrane, which is made of butadiene rubber or rubber.

The formation of a pore system occurs due to the fact that a laser beam with a temporary structure is formed in the form of periodically repeating series of light pulses with an intensity sufficient to burn cylindrical pores in the material of the elastic membrane. The material of the elastic membrane is affected by the generated laser beam through spatial scanning, which consists in the scanning of each series of pulses on the membrane. The membrane surface is scanned in a cyclic (intermittent) mode. In this case, the beginning of the sweep of each series of pulses on the membrane surface is synchronized with the beginning of the formation of the previous series of pulses. At the end of a series of pulses, scanning and, accordingly, the sweep of a series of pulses are interrupted. Thus, in the cyclic mode, a series of pulses are sequentially developed one after another and cover the entire surface of the membrane. In the proposed method, a laser beam is formed with the formation of a series of pulses of 10-100 pieces of pulses in a series. Typically, the energy of one pulse with a duration of 10 ns does not exceed one joule. In the case of the generation of a series of pulses with a wavelength of 1064 nm of 10-100 pieces with a frequency of 1-39 kHz, a duration of 10 ns, the energy is distributed between many pulses that are separated by time intervals.

The formation in the membrane of a system of cylindrical pores is performed with a specific specific power of laser radiation, usually 1 J / cm ² .

Example. Precipitation of rabies virus. For the concentration of rabies virus, a substrate culture is prepared from sucrose - 5.5%, cesium chloride - 2.2%, glycerol - 92%, radiation is carried out for 1-2 hours. Filtering is carried out under the influence of the pressure difference between the compartments within 20-30 kPa. The virus is separated from the liquid cultures by generating laser pulses on a 0.23 micron rubber membrane. The membrane is made of rubber having an elastic modulus of 10 MPa, which has the ability to self-tighten pores after the formation of a channel system in it. To generate laser pulses, a Cr: YAG type laser is used, which generates a series of laser pulses with a single pulse energy of 0.12 J at a pulse repetition rate of 39 kHz, a total of 25 pieces in a series. Under conditions of exposure to the membrane surface with an energy of 1 J / cm ^{2, a} series of 25 radiation pulses forms pores in the membrane of rubber with a size of less than 80-180 nm.

As a result, 99.3% of the virus was concentrated.

It should be noted that the proposed method is used to sterilize fluid from rod bacteria and viruses, for this, the pore size in the membrane is less than 0.5-1.0 μm, and for sterilizing fluid from viruses, the pore size in the membrane is less than 20-300 nm.

Claims (2)

1. A method of filtering solutions or suspensions of microorganisms or proteins by passing through a porous membrane, characterized in that the filtering is carried out through a continuous elastic membrane of rubbers or rubber, to start filtering form a system of pores not exceeding the size of the concentrate using pulsed laser radiation with a power not more than 1 J / cm ² , and the membrane material has the ability to self-tighten pores after the cessation of pulsed laser exposure. 2. The method according to claim 1, characterized in that for the formation of a pore system for a concentrate with a size of 0.5-1.0 μm, the elastic modulus of the elastic membrane is 10-20 MPa, the frequency of the pulsed laser radiation is 1-39 kHz, the wavelength is 1064 nm, pulse duration - 10 ns.