WO2006092082A1

WO2006092082A1 - A method for the dryness preservation of biological fluid samples and the device thereof

Info

Publication number: WO2006092082A1
Application number: PCT/CN2005/000262
Authority: WO
Inventors: Ge Chen
Original assignee: Ge Chen
Priority date: 2005-03-04
Filing date: 2005-03-04
Publication date: 2006-09-08

Abstract

The present invention provided a method for the dryness preservation of biological fluid samples comprising the steps of contacting the said samples with a porous solid support with an average diameter from 0.1 mm to 5 mm and removing the aqueous solution from the solid support which has absorbed the samples. The porosity of the dried solid support is at least 20 %. The invention also provided a device for the method.

Description

Method and apparatus for dry preservation of liquid samples

The invention relates to a method for drying and preserving a liquid sample based on a porous material, in particular to a method for drying and storing a biological sample. The invention also relates to a device for drying, preserving a liquid sample. Background technique

The collection, preservation, transportation, recombination and recovery of biological samples in scientific research are prerequisites for various experimental scientific research and medical clinical indicators. Liquid biological samples are the most widely used form of biological samples in life science research. How to use the most simple and cost-effective method to maintain the effective activity (including binding activity and biological activity) and integrity (such as cells and other formation) of the original sample contents The accuracy of the concentration of the sample after reconstitution and recovery and the safety during the whole process of biological sample processing are one of the basic problems that need to be solved in the fields of biology, medicine, medicine and biotechnology. For many years, scientists have made unremitting efforts to this end.

At present, the preservation methods of liquid samples are mainly divided into liquid cryopreservation (2-8 degrees Celsius); cryopreservation (-20 ~ -200 degrees Celsius); frozen (Celsius -60 degrees or less) dry preservation; low temperature dry preservation (Celsius 2-8 degrees); and dry at room temperature (10 ~ 30 degrees Celsius or ambient temperature).

The existing methods have different shortcomings: for example, in a normal temperature environment, the components of the biological liquid sample are rapidly degraded in a short period of time or the bacterial mold is propagated, which causes changes in the properties of the original liquid sample; the liquid sample in a low temperature environment is not suitable for long-term storage; The storage of frozen liquid samples requires a cryogenic water tank to keep the temperature below 0 °C, which is inconvenient for sample transportation. Although the freeze-dried liquid sample can obtain satisfactory sample recovery efficiency, its cost is too high and it is not suitable for single or small batch liquid. Sample processing; The current normal temperature dry sample storage method solves the problem of dry storage and transportation of liquid samples, but there are many defects in sample liquid recovery, recombination and subsequent analysis and processing.

Robert Guthrie first used Schleicher & Schuell Bioscience in 1963 The company's (S&S) 903 filter (hereafter called Guthrie Card) has been used for the dry storage of biological fluid samples since the collection of neonatal blood samples for PKU screening. However, since the absorption matrix of the sample is composed of cellulose, when a liquid sample such as blood is dried to form a fiber/sample solid structure, it is difficult to recombine and recover the liquid sample, and the application range thereof is greatly limited. . In summary, the main disadvantage of using cellulose membrane as a liquid sample absorption matrix is that the sample is time-reorganized, usually takes at least 30 minutes to several hours, and needs heat treatment to promote reconstitution of the sample; low recovery efficiency, formed by drying The sample cellulose film matrix is a non-gap substantive structure, so it is extremely difficult to hydrate the dried sample again; and the cellulose film has low recovery rate for absorption and adsorption of the sample components, and the optimal recovery rate is lower than a short time. 50%. Prerequisites. Joseph (USA; Pat. No.: 5432, 097) described in 1993 the use of enzymatic digestion of the cellulose membrane (Guthrie Card) method for white blood cell recovery of dried blood. However, this method requires the use of cellulase to degrade the cellulose membrane, which is time consuming and costly.

Therefore, there is a need in the art for a dry process for liquid samples that is easy to handle, fast, and has high sample recovery. Summary of the invention

The present invention provides a method for dry preservation of a liquid sample, comprising: contacting the liquid sample with a porous solid support having an average pore diameter of 0.01 mm to 5 mm; and removing a liquid component from a solid support from which the liquid sample is absorbed; The porosity of the solid support after drying is at least 20% of the original porosity of the solid support.

According to an embodiment of the invention, the porous solid support is composed of one or more materials selected from the group consisting of: polymeric materials, chemically or untreated biologically derived materials, metallic materials, and inorganic non-organic materials. metallic material. .

According to another embodiment of the invention, the liquid sample is a biological fluid, a manually formulated biological fluid sample or a liquid biological reagent.

The present invention also provides an apparatus for dry-preserving a liquid sample comprising a sample having an average pore diameter of 0.01 mm to 5 mm, which retains the original porosity after drying and retaining at least 20%. A porous solid support.

According to the method and apparatus of the present invention, rapid, decanid dry storage of liquid samples can be achieved, and samples can be recovered quickly and efficiently as compared to prior art methods. DRAWINGS

The invention is described in detail below with reference to the drawings and specific embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a schematic diagram showing the process of drying, preserving, recovering, and reconstituting blood samples using the method of the present invention. Figures 1A-D show the reconstitution of a porous solid support prior to unloading, a porous solid support after absorption of a liquid sample (whole blood), a dehydrated loaded solid support, and a blood sample, respectively.

Figure 2 is an electropherogram of genomic DNA recovered from a blood sample preserved by the method of the present invention. In the figure, M is a molecular weight marker; "1 - 4" is DNA extracted from 4 blood samples dried on the solid carrier of the present invention, respectively. The amount of sample loaded per sample was 1 microgram (DNA). detailed description

The inventors of the present invention have extensively studied and found that a porous solid carrier using a large pore can not only rapidly absorb and dry a liquid sample, but also a dried sample can be easily eluted from a carrier with water or other solvent, thereby being quickly and efficiently recovered. Reconstitute the sample.

Accordingly, the present invention provides a method of dry preservation of a liquid sample comprising contacting the liquid sample with a porous solid support having an average pore diameter of from about 0.01 mm to about 5 mm; and from absorbing a liquid sample The liquid component is removed from the solid support; wherein the solid support has a porosity of at least 20% of the original carrier after drying.

In the process of the present invention, the porous solid support used preferably has an average pore diameter of from about 0.05 mm to about 1 mm, more preferably from about 0.1 mm to about 0.5 mm.

In the process of the present invention, the porosity of the porous solid support after loading and drying preferably maintains at least about 30%, more preferably at least about 40%, and most preferably at least about 50% of the original porosity.

The porous solid support of the present invention may be made of any material, such as one or more materials selected from the group consisting of: polymeric materials, chemically treated or untreated biological sources. Materials of materials, metallic materials and inorganic non-metallic materials. In a preferred embodiment, the porous solid material of the present invention is a polymeric material.

The porous solid support of the present invention can be a single unitary material. The material is formed into a plurality of surface openings through its preparation process, or the material naturally has a plurality of surface openings.

The porous solid support of the present invention may also be a solid material having a plurality of surface openings formed by physical or chemically fixed arrangement of a plurality of units of various shapes. The unit constituting such a solid material may itself have a porous structure or no porous structure. Methods of arranging such units in a fixed manner are known to those skilled in the art, such as mechanical joining, bonding, weaving, and the like.

The porous solid carrier of the present invention has a certain hardness to avoid collapse of the porous structure due to liquid gravity or drying process after the liquid is carried, resulting in the porosity of the loaded solid carrier after drying being less than 20% of the original porosity of the carrier. Not conducive to the reconstruction of the sample.

The polymeric materials of the present invention may be non-biocompatible and/or biodegradable, or may be biocompatible and/or biodegradable. In environmental considerations and for preservation of live cells, microbial samples, it is preferred that the polymeric materials of the present invention are biocompatible and/or biodegradable.

Examples of biocompatible and/or biodegradable polymeric materials are: hydroxycarboxylates such as poly(3-hydroxybutyrate) (PHB), 3-hydroxybutyrate and 3-hydroxyhexanoate Copolymer (PHB-HH), polylactic acid (PLA), lactic acid-glycolic acid copolymer (PLGA), polycaprolactone, polyorthoester, polyanhydride, and the like. For blood compatibility, polymeric materials having excellent anticoagulant properties include, for example, hydrophilic materials such as poly(methyl methacrylate), polyvinyl alcohol, polymethacrylamide, and polyvinylpyrrolidone; A hydrophobic material such as silicone rubber; a polymer material having a surface of a microphase-separated structure such as polyether urethane; and a material having a negatively charged surface such as polyester and foamed polytetrafluoroethylene which are surface-evaporated smooth carbon film.

Examples of non-biodegradable materials are: polyvinyl acetate, polyethylene, polystyrene, polyvinyl chloride, polyurethane, polycarbonate, and the like.

The porous polymeric material can be conveniently obtained by prior art methods, such as by methods such as polymer foaming. The pore size of the porous polymeric material can also be controlled in a conventional manner to obtain a porous material suitable for a particular application. It is known to those skilled in the art that almost all thermosetting and thermoplastic resins can be made into a foamed polymer, i.e., a porous polymeric material. Polymers which are often used to prepare porous polymeric materials are: polystyrene, polyurethane, polyvinyl chloride, polyethylene, urea furfural resin, phenolic resin, and the like.

The foaming method for causing the polymer to produce a porous structure includes mechanical foaming, physical foaming, chemical foaming, and the like.

Mechanical foaming is a process in which a gas is mixed into a liquid polymer material by mechanical agitation, and then a cell is formed through a shaping process. The mechanical foaming method can be used for a urea furfural resin, a polyvinyl formal, a polyvinyl acetate, a polyvinyl chloride sol or the like.

The physical foaming method utilizes a change in the physical state of the blowing agent to produce pores in the polymer material. Physical blowing agents include compressed gases, volatile liquids, and soluble solids. Compressive gases such as nitrogen, carbon dioxide, etc., expand in volume when the pressure is lowered to produce pores. Volatile liquids are vaporized to produce pores such as low boiling aliphatic hydrocarbons, 13⁄4 aliphatic hydrocarbons and low boiling alcohols, ethers, ketones and aromatic hydrocarbons. The soluble solids are removed by dissolution to produce angry pores in the polymer product, such as water-soluble inorganic salts, water-soluble polymers, and starch. For example, monochloromethane and methylene chloride are commonly used in the manufacture of styrofoam, while fluorohydrocarbons are used in the manufacture of a variety of foams, such as foamed polyethylene, styrofoam, soft and rigid polyurethane foams, urea-formaldehyde foams. And phenolic foam and the like.

The chemical foaming method is one in which a chemical foaming agent added to a polymer solution is chemically changed or thermally decomposed at a certain temperature to produce one or more gases, thereby producing an angry pore in the polymer product. Chemical blowing agents include inorganic foaming agents and organic foaming agents. Inorganic foaming agents mainly include ammonium carbonate, ammonium hydrogencarbonate and sodium hydrogencarbonate. The organic foaming agent mainly includes a nitrosamine compound, an azo compound, a sulfonyl hydrazide, and a urea derivative.

For example, a method for preparing a porous polymer material using an inorganic salt physical foaming agent is disclosed in Chinese Patent No. CN 11 17587C. The method comprises dissolving a polymer such as polylactic acid in a solvent such as chloroform or dioxane, and then adding a foaming agent having a particle diameter equivalent to a predetermined pore diameter such as sodium chloride, potassium chloride or the like to the polymer solution. The mixture is then added to a mold, dried, and stripped, and the article is immersed in deionized water for a period of time. The soaked product is dried to obtain a porous polymer material. According to the description of the document, a pore size of 50 - 500 microns can be obtained. Porous material.

In a preferred embodiment of the invention, the polymeric material constituting the porous solid support is an open cell polymeric foam obtained by a foaming process, including a sponge-like polymeric material.

The porous solid support in the present invention preferably has a porosity of 30% or more, more preferably 40%, 50%, 60%, 70% or even 80% or more.

In a preferred embodiment of the invention, the porous solid support is a water absorbent foam polymer. The water-absorbent foam polymer can be obtained by a conventional method using a highly hydrophilic polyol. For example, a polyester type fast-absorbing foam can be obtained according to the following formula: 100 parts of diethylene glycol adipate (weight, the same below), 46 parts of TDI-80, 6 parts of ethoxylated monooleate, 1.1 parts of amine catalyst, 0.5 part of foam stabilizer and 3.5 parts of water.

The porous metal material of the present invention includes a powder metallurgy porous material, a sintered metal fiber porous material, a sintered metal mesh porous material, a foamed metal material, and the like. The metal for producing the metal foam is selected from the group consisting of Al, Cu, Ni, Fe, Mg, Zn, Pb, Sn, Ag, Cr, Mo, Co, and the like, and alloys thereof.

The powder metallurgy porous material is a porous material which is formed by metal powder as a raw material through forming, sintering and the like. The metal powder for producing the powder metallurgy porous material may be an irregularly shaped powder or an approximately spherical powder.

The sintered metal fiber porous material is a porous material which is formed by a process of forming, sintering, or the like of a metal fiber.

The sintered metal mesh porous material is a monolithic porous material prepared by a process such as rolling or sintering (vacuum or atmosphere) or hot pressing using a single layer or a plurality of metal meshes. The wire mesh can be woven into a Plain Weave, a Twill Weave, a Plain Dutch Weave, and a Dutch Twill Weave.

Foam metal refers to a lightweight porous metal having a relatively high porosity, a large pore size, and interconnected pores. The structure of the metal foam has a skeleton structure, a honeycomb structure composed of a film, and the like. Common methods for producing foam metal include a molten metal foaming method, a metal slip foaming method, an infiltration slurry sintering method, and an electroforming method.

The inorganic non-metallic material of the present invention comprises a porous material made of a ceramic, glass, cement, refractory or the like by a conventional method in the art, wherein the chemical composition of the inorganic non-metallic material These include silicates, other oxoacids, oxides, nitrides, carbons and carbides, borides, fluorides, sulfur compounds, silicon, germanium, III-V and II-VI compounds.

For example, a porous ceramic is a ceramic material which is fired at a high temperature and has a large number of pore structures in the body which communicate with each other and which also penetrate the surface of the material. The method for forming a porous ceramic from a ceramic material comprises forming a porous ceramic by stacking and bonding of aggregate particles; using some additives to burn or volatilize at a high temperature to leave pores in the ceramic body; utilizing thermal decomposition of the material, phase The pores are formed by morphing and segregating; the ceramic slurry is adsorbed by the burnable porous carrier, and then the carrier material is burned at a high temperature to form a pore structure.

The porosity of the porous solid support of the present invention can be measured by a conventional method in the art. For example, the method of indirectly measuring porosity is a method of measuring density by the formula ε = ( \ - £L )

χ 100 % means that ε is the porosity of the material, _Α is the average density of the total volume of the porous material, and Α is the density of the solid part of the material. The porous solid carrier of the present invention can be used as it is without any treatment. However, in order to prevent contamination of the sample, it is preferred to wash with water, a detergent aqueous solution, or with an acid or alkali solution. For example, the pH of the acidic solution used is below 5.0, and the pH of the alkaline solution is above 8.0. The solid support treated with an acid or a base may be washed with water to remove residual acid or alkali components. It may also optionally be left untreated after treatment with an acid or base to maintain the solid support in an acid or alkaline environment until dehydrated.

The porous solid support of the present invention may be specially treated by one or more of the following methods, depending on the particular application.

Heat treatment of porous solid carrier; autoclave treatment; ultraviolet irradiation; radioactive irradiation; preservative treatment; antibiotic treatment; antifungal treatment; organic solvent treatment, examples of organic solvents are ethanol, isopropanol, Acetone, chloroform, phenols, ethers, etc.; detergent treatment, examples of detergents are Tween (Tween-20, Tween-100), sodium dodecyl sulfate (SDS), etc.; anticoagulant Examples of treatments, anticoagulants are heparin, sodium citrate (salt), ethylenediaminetetraacetic acid (EDTA) and the like.

For example, a protein-containing liquid can be used to block the protein binding site on the inner and outer surfaces of the porous solid support, preventing adsorption of protein molecules in the sample to cause a decrease in sample recovery efficiency. As another example, various chemical groups can be chemically coupled to the inner and outer surfaces of the porous solid support to facilitate adsorption of inclusions in the liquid sample, such as amino, carboxyl, hydroxyl, alkyl or other chemical groups.

It is also possible to physically or chemically coat or bind appropriate molecules such as various protein molecules, nucleic acid molecules, acid substrates, etc. on the carrier to specifically or non-specifically capture the corresponding components contained in the sample.

The liquid sample in the present invention is defined as any mixture containing a substance to be stored in an aqueous or non-aqueous solvent which exists in a liquid state. The sample mixture can be in the form of a solution, suspension, emulsion or any other liquid form.

For example, the liquid sample of the present invention may be a physiological or pathological biological fluid: blood, sweat, urine, cerebrospinal fluid, spinal fluid, joint cavity fluid, vaginal secretion fluid, semen, plasma, serum, amniotic fluid, milk, pleural fluid, peritoneal fluid The liquid sample of the present invention, such as bone marrow fluid, saliva, bile, tear fluid, etc., may also be a manually prepared liquid sample, such as a liquid containing bacteria, mold, fungi, parasites, etc., a liquid extract of various biological tissues such as Biological various cell or/and tissue extracts (liquid extracts of heart, liver, spleen, lung, kidney, etc.) and liquid extracts of various plant cells, and the like.

The liquid sample of the present invention may also be a liquid reagent containing a solid solute such as various buffers and a liquid prepared therefrom. The liquid prepared from the liquid reagent is, for example, a liquid containing proteins, nucleic acids, cells, platelets, bacteria, plasmids, virus particles, parasites, semen, vaginal secretions and the like.

In the process of drying and storing the liquid sample by the method of the present invention, a protective agent capable of improving the tolerance of the biologically active substance to drying and improving the preservation ability may be added. Such protective agents are well known to those skilled in the art. For example, polyols such as glucose, maltose, sucrose, xylulose, ribose, mannose, fructose, raffinose, trehalose and the like; sugar derivatives such as sorbitol; synthetic polymers such as polyethylene glycol, Hydroxyethyl starch, polyvinylpyrrolidone, polyacrylamide; polysaccharides such as polysucrose and dextran; proteins; and combinations of the foregoing.

For the preservation of platelets, for example, examples of protective agents that can be added are serum proteins, Casein hydrolysate, polyvinylpyrrolidone and hydroxyethyl starch.

For the preservation of nucleic acids such as RNA, DNA, oligonucleotides, etc., SDS, hydrazine, Tween, etc. may be added.

In a preferred embodiment of the invention, the liquid sample is a whole blood sample or a sample of blood components of a human or animal.

The dehydration after the liquid sample is added to the solid carrier can be carried out under natural room temperature evaporation, or can be heated (such as in an oven at 37 degrees Celsius), hot air (such as a hair dryer), and the liquid component of the liquid sample can be accelerated under reduced pressure. Removal forms a dry sample.

As described above, the present invention also provides an apparatus for drying a liquid sample, which comprises a macroporous porous solid support. The above description and preferred conditions regarding the method of the invention are equally applicable to the apparatus of the present invention.

In the apparatus of the present invention, the porous solid support may be of any shape suitable for its supporting member, such as a sheet, a cylinder, a cube, a sphere or the like.

The dry-absorbed sample according to the present invention is easily recovered from the solid support by conventional operations such as washing, centrifugation, etc., and the liquid sample is reconstituted. Reconstituted liquid samples can be used for subsequent operations and applications such as detection, purification, etc. of sample contents, such as detection and purification of various proteins, ions, vitamins, antigens, antibodies, cells, nucleic acids, and the like.

According to the method of the present invention, the content of the sample is recovered quickly and the recovery rate is high. For example, the sample recovery operation can be completed in seconds to minutes. The sample stored dry in accordance with the present invention may have a recovery of at least about 70%, preferably at least 80%, more preferably at least 90%, and most preferably at least 95%.

The methods and devices of the present invention are preferably applicable to the dry preservation of various biological cells. For example, red blood cells (RBC), white blood cells (WBC), platelets, etc. in the blood are stored dry. The solid support is preferably pretreated prior to absorbing the cell sample, such as by encapsulation with a protein-containing liquid, and treatment with a concentration of a cell fixative such as formalin, an aldehyde, an ether, an alcohol or the like. When the cellular components in the sample are contacted with the above preservative or fixative, the cellular components are fixed and subsequently dehydrated to form an immobilized dehydrated dried cell sample. After the sample is added with a suitable solvent, the cells can be hydrated again, and the original structural form can be restored, which can be further applied to histochemical staining and immunohistochemistry of cells. Staining, immunofluorescence staining, detection of cell surface molecules, sorting or purification of specific cells, such as sorting cells by magnetic beads or by flow cytometry or classification detection.

The method and apparatus of the present invention are preferably applied to dehydration or vitrification preservation of various protein molecules, particularly various antigens, antibodies, various enzymes, in combination with suitable stabilizers. An advantage of the method of the present invention is that the above-mentioned molecules can stably maintain their binding activity and/or enzymatic activity for a long period of time when they are in a dehydrated dry state or a vitrified state. When the solvent is added, the above components can be rapidly hydrated in a short period of time (usually within 5 minutes) and distributed in the liquid phase, thereby allowing effective reaction with the corresponding ligand or substrate.

The method and apparatus of the present invention are also preferably applied to the collection, drying and storage of blood samples. The solid carrier may be treated with an anticoagulant or directly mixed with an anticoagulant such as heparin or disodium EDTA prior to blood sample collection. The blood sample collection is directly taken by finger puncture blood collection or sole puncture (infant) blood collection method. The blood droplets are allowed to drip directly into the porous solid carrier and then dehydrated to form a mixture of anticoagulated dry blood microparticles and a solid carrier. Blood can also be collected by conventional venipuncture, and blood is quantitatively transferred to the above porous carrier using a pipette. When the sample is reconstituted, for example, a solvent (usually pure water or distilled water) equivalent to the volume of the original blood sample is added to quickly obtain a reconstructed blood sample close to the original sample, which can be used for further processing such as analysis and analysis. Depending on the purpose of the application, it is also possible to directly drop blood into a solid carrier which is not treated with an anticoagulant without using an anticoagulant to prepare a dried blood sample.

Example

Example 1

Preparation of porous solid materials

The operation was carried out substantially in accordance with the method of Example 1 in CN 1117587C. Namely, 2.0 g of poly-3-hydroxybutyrate was weighed and introduced into 20 ml of chloroform. The polymer was completely dissolved by heating in a water bath at 65 ° C for 30 minutes. To the solution was added 60 g of sodium chloride particles having a pore size ranging from 0.2 to 0.4 mm, and the mixture was thoroughly stirred to homogenize the mixture. The above mixture was poured into a mold and clamped under a pressure of 0.2 MPa. Dry at room temperature for 48 hours. The mold was then released and the shaped article was dried in a vacuum oven at O.OMPa for 48 hours. The product was then immersed in 200 ml of de-watered water and replaced with fresh deionized water every 8 hours. Take after 72 hours Produce products. The final product was obtained by placing the article in a vacuum oven at O.OMPa for 48 hours.

Example 2

Using Example 1 porous solid material to dry and preserve blood samples

From the porous polylactic acid material obtained in Example 1, a cylinder having a thickness of 0.6 cm and a diameter of 1.1 cm was taken. The cylindrical porous material is fixed to the inner surface of the centrifuge tube lid. 0.5 ml of heparin-added whole blood samples were hooked onto the above porous material. The porous material loaded with the blood sample described above was dried in a ventilated room at room temperature until the water content in the blood sample was less than 2%. The lid carrying the dried sample is brought into close contact with the centrifuge tube until use.

Parallel to this, another 0.5 ml blood sample from the same source was used to determine the hemoglobin content.

Example 3

Dry blood sample recovery

The centrifuge tube with the dried sample obtained in Example 2 was opened, and about 0.6 ml of deionized water was added to the centrifuge tube. Cover the lid and invert the tube to allow the water to contact the porous material for approximately 5 minutes. Then, the centrifuge tube is swayed several times or slightly centrifuged upward to obtain a reconstructed blood sample.

The recovery of the blood sample was calculated to be about 96% by measuring the hemoglobin content of the sample and comparing it with the control hemoglobin content of the example.

Example 4

Drying and preserving blood samples using sponge-like polymer materials

The same procedure as in Example 2 was carried out, except that a commercially available polymer sponge (pore size range of 0.2 - 2.0 mm) was used instead of the polylactic acid porous material. The blood sample was recovered by the same procedure as in Example 3. The recovery of the blood sample was about 93% based on the amount of hemoglobin.

Example 5

Extracting genomic DNA from dried blood samples

A 0.25 ml blood sample was dried and stored as in Example 4. Add 1 ml of red blood cell lysate to a 1.5-liter centrifuge tube with a blood-loaded porous carrier to make it The solid support was contacted for 5 minutes. Shake the tube and centrifuge at maximum speed for 15 seconds on an Eppendrof centrifuge. Aspirate the supernatant. Add 1 ml of red blood cell lysate, shake the tube, centrifuge, and discard the supernatant.

Add 0.3 ml of DNA release solution to the test tube, mix with the leukocyte pellet and allow to stand for 5 minutes. Then, 0.1 ml of the protein precipitate was added, mixed, and centrifuged for 5 minutes.

The supernatant containing the genomic DNA was transferred to a test tube, and the DNA concentration was measured. Electrophoresis was carried out in a conventional manner to identify the quality of DNA (see Figure 2 for results).

A 0.25 ml fresh blood sample from the same source was used as a parallel control.

Results The average DNA recovery for the 4 experiments was 35 μg, and the average recovery from fresh blood was 36 μg.

Example 6

Recovery of serum T3, Τ4 and TSH

0.2 ml of serum was added to the same porous carrier as in Example 4, and dried at room temperature for 3 hours. Store at room temperature for 1 month after sealing.

The above solid support with dried serum samples was contacted with 0.2 ml of distilled water for 10 minutes. After centrifugation, the supernatant was taken out. The concentrations of Τ3, Τ4 and TSH were measured by chemiluminescence. The same determination was performed on frozen serum samples of the same source.

As a result, it was found that the average recovery rate of the three experiments of the above factors (relative to the frozen sample) was close to 98%.

Claims

Rights request

A method for dry-preserving a liquid sample, comprising: contacting the liquid sample with a porous solid support having an average pore diameter of 0.01 mm to 5 mm; and removing a liquid component from the solid support from which the liquid sample is absorbed; The solid support has a porosity of at least 20% of the original carrier after drying.

The method according to claim 1, wherein said porous solid carrier has an average pore diameter of from 0.05 mm to 1 mm.

The method according to claim 2, wherein said porous solid support has an average pore diameter of from 0.1 mm to 0.5 mm.

4. The method of claim 1 wherein the dried solid support has a porosity of at least 30% of the original porosity of the support.

5. The method of claim 1 wherein the dried solid support has a porosity of at least 40% of the original porosity of the support.

6. The method of claim 1 wherein the dried solid support has a porosity of at least 50% of the original porosity of the support.

7. The method according to claim 1, wherein the porous solid support is composed of one or more materials selected from the group consisting of: polymeric materials, chemically or untreated biologically derived materials, metallic materials And inorganic non-metallic materials.

8. The method according to claim 7, wherein the polymer material is obtained by a crosslinking method, a foaming method, a fiber non-woven molding method, or a fiber weaving.

9. A method according to claim 8 wherein said polymeric material is an open cell polymeric foam prepared by a foaming process.

The method according to claim 7, wherein the metal material is a metal foam material, a powder metallurgy porous material, a sintered metal fiber porous material or a sintered metal mesh porous material.

The method according to claim 10, wherein said metal foam is produced by a molten metal foaming method, a metal slip foaming method, an infiltration slip sintering method or an electroforming method.

12. The method according to claim 7, wherein the inorganic non-metallic material is a porous material made of ceramic, glass, cement or refractory material.

13. The method according to claim 1, wherein said removing the liquid component from the solid carrier is carried out by air drying.

14. The method according to claim 1, wherein said removing the liquid component from the solid carrier is carried out under reduced pressure.

15. The method of claim 1 wherein the liquid sample is a biological fluid, a human formulated biological fluid sample, or a liquid biological reagent.

16. A method according to claim 15 wherein the biological fluid is blood or a component thereof.

17. A device for dry preservation of a liquid sample comprising a macroporous porous solid support.