RU2499003C1 - Method of producing polyacrylamide hydrogel - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: method is realised by polymerising an aqueous solution containing 7-15 wt % acrylamide and 0.5-1.5 wt % N,N'-methylene bisacrylamide under the action of a redox system: ammonium persulphate and N;N,N',N'-tetramethyl ethylenediamine, wherein polymerisation is carried out in the presence of 0.01-0.12 wt % mercaptoacetic acid.

EFFECT: high structural homogeneity of the hydrogel.

2 tbl, 5 ex

Description

The invention relates to the field of polymer chemistry, biochemistry and medicine, and in particular to a method for producing polyacrylamide hydrogel, which due to its high porosity is used as a separating medium in liquid chromatography, as a carrier of immobilized biologically active substances, and also for the manufacture of soft tissue endoprostheses.

A known method of producing a polyacrylamide hydrogel by γ-irradiation with a dose of 0.5-5.0 Mrad of powdered polyacrylamide followed by the addition of water and mechanical homogenization of the mixture [RF patent 2114867, C08F 120/56, 1998].

The disadvantage of this method is the heterogeneous structure of the resulting hydrogel, due to the presence of pores of different sizes. All pores of the hydrogel are available for insulin molecules with a molecular mass (MM) of 6000 and serum albumin molecules with an MM of 67,000, 70-80% of the pores are available for alcohol dehydrogenase molecules with an MM of 141,000, and 40-50% of the pores are available for fibrinogen molecules with an MM of 340000.

The closest in technical essence and the achieved results is a method for producing a polyacrylamide hydrogel by polymerization of an aqueous solution containing 7-15% wt. acrylamide and 0.5-1.5% wt. N, N′-methylenebisacrylamide, under the action of a redox system: ammonium persulfate and N, N, N ′, N′-tetramethylethylenediamine [Research Methods in Immunology, ed. I. Lefkovits and B. Pernis, Mir, Moscow, pp. 99-107].

The disadvantage of this method is the structural heterogeneity of the resulting hydrogel, due to the wide pore size spread. Depending on the amount of acrylamide and N, N′-methylenebisacrylamide, the resulting hydrogels in the swollen state contain 80-95% water, all the pores of the hydrogels are available for insulin molecules, 90-95% of the pores are available for ovomucoid molecules with MM 31000, 80-90% pores are available for serum albumin molecules, 50-60% of the pores are available for alcohol dehydrogenase molecules, and 30-40% of the pores are available for fibrinogen molecules.

The objective of the invention is to increase the structural uniformity of the hydrogel.

The technical result achieved by using the invention is to increase the structural uniformity of the hydrogel.

The technical result is achieved by the fact that in the method for producing a polyacrylamide hydrogel by polymerization of an aqueous solution containing 7-15% wt. acrylamide and 0.5-1.5% wt. N, N′-methylenebisacrylamide, under the action of a redox system: ammonium persulfate and N, N, N ′, N′-tetramethylethylenediamine, polymerization is carried out in the presence of 0.01-0.12% wt. mercaptoacetic acid.

Mercaptoacetic acid is a chain transmitter in radical polymerization and in the homopolymerization of unsaturated monomers provides a decrease in their molecular weight without changing the polymerization rate. In copolymerization reactions with the formation of porous hydrogels, this compound was not used.

Example 1

At room temperature and stirring in 89 ml of distilled water, 10 g of acrylamide (AA) and 0.5 g of N, N-methylenebisacrylamide (BIS) are dissolved. After complete dissolution, 0.08 g of ammonium persulfate (PA) and 0.04 g of mercaptoacetic acid (MUA) are added to the solution. The solution was evacuated at 10-12 mmHg, 0.08 ml of N, N, N ′, N′-tetramethylethylenediamine (TEMED) was added to it. The solution is evacuated at 10-12 mm Hg. and incubated at room temperature (18-21 ° C) for 5 hours. The completion of the polymerization reaction is indicated by the formation of a colorless gel. The resulting gel is removed from the vessel, crushed by forcing through a sieve with a pore diameter of 1 mm and washed with a 10-fold excess of distilled water. The water content of the hydrogel is estimated by weighing the water-swollen hydrogel and freeze-dried hydrogel. To evaluate the content of pores of various sizes in the hydrogel, 4 ml of a protein solution is added to 2 ml of the gel and the mixture is incubated for 48 hours at 4 ° C. The concentration of the initial protein solution and the protein solution after contact with the hydrogel is measured spectrophotometrically at 280 nm using a previously constructed calibration dependence. Given the ratio of the volumes of the phases used, the number of pores available for each protein is calculated, taking as 100% the number of pores available for water. The hydrogel properties are shown in table 2.

Examples 2-4

The process is carried out as in example 1, using various amounts of components. The composition of the reaction mixture are shown in table 2

Example 5 (control)

The process is carried out as in example 1 without the use of mercaptoacetic acid.

Table 1 Example No. Water ml AA g Bis, g PS, g TEMED, ml MUK, g one 89 10 0.5 0.08 0.08 0.04 2 92 7 0.5 0.06 0.08 0.01 3 86 12 1,5 0.08 0.08 0.12 four 84 fifteen 1,0 0.10 0.10 0.08 5 (cont.) 89 10 0.5 0.04 0.04 -

table 2 Example No. The water content in the hydrogel,% The pore content of the hydrogel (%) available for protein with molecular weight 6000 31000 67000 141000 340000 one 84 one hundred 77 62 thirty 7 2 86 one hundred 80 72 37 fourteen 3 95 95 84 70 23 6 four 93 97 82 75 28 12 5 (cont.) 89 one hundred 91 82 51 38

It can be seen that the use of mercaptoacetic acid in the process of radical polymerization of N, N′-methylenebisacrylamide acrylamide leads to the production of more uniform finely porous hydrogels with a low pore content of large size. So, if in the hydrogel obtained by the prototype method, all the pores are sized to provide accessibility for water molecules and protein molecules with MM 6000, and 38% of them are available for protein molecules with MM 340000, then in hydrogels obtained by the proposed method , the number of pores available for protein molecules with MM 340000, reduced by 2.8-5.4 times.

The limiting amounts of mercaptoacetic acid introduced into the reaction (0.01-0.12% by weight) are determined as follows. At a concentration below 0.01% wt. the effect of changing the structure of the hydrogel is practically absent, and at a concentration above 0.12% wt. hydrogel does not form.

Claims (1)

A method of producing a polyacrylamide hydrogel by polymerization of an aqueous solution containing 7-15 wt.% Acrylamide and 0.5-1.5 wt.% N, N′-methylenebisacrylamide, under the action of a redox system: ammonium persulfate and N, N, N ′, N′-tetramethylethylenediamine, characterized in that the polymerization is carried out in the presence of 0.01-0.12 wt.% Mercaptoacetic acid.