Weighted collagen microsponge for immobilizing bioactive materials
First Claim
1. A method of preparing a weighted collagen microsponge for immobilizing bioactive materials in motive bioreactor systems, said microsponge comprising a porous, biostable, insoluble highly crosslinked collagen matrix containing an inert weighting material, said collagen matrix having an open to the surface pore structure with an average pore size in the range of from about 1 micron to about 150 microns, the pores of said matrix occupying from about 70 to about 98% by volume of the microsponge, said microsponge also having an average particle size of from about 100 to about 1000 microns and a specific gravity above about 1.05 wherein said weighted collagen microsponge is prepared by the steps of(a) milling a source of collagen selected from the group consisting of Types I, II, and III collagen to produce collagen fibers,(b) admixing said milled collagen with an acidic liquid medium,(c) adding inert weighting material to said acid/collagen mixture,(d) producing droplets of the weighted acid/collagen mixture of step (c),(e) rapidly solidifying said droplets by freezing to form solid particles of a frozen collagen fiber matrix,(f) thermally soaking said solid particles by holding said particles at a temperature at which said particles remain frozen and for a period of time and under conditions sufficient to allow partial agglomeration of said collagen fibers to occur,(g) vacuum drying said solid particles into a dry, porous matrix, and(h) crosslinking the collagen in said dry, porous matrix to produce said weighted collagen microsponge.
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Abstract
Weighted collagen microsponges having a highly crosslinked collagen matrix are described suitable for use in culturing organisms in motive reactor systems. The microsponges have an open to the surface pore structure, and pore sizes and volumes suitable for immobilizing a variety of bioactive materials. The microsponges also have an average particle size in the range of about 100 to about 1000 microns and a specific gravity above about 1.05.
75 Citations
35 Claims
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1. A method of preparing a weighted collagen microsponge for immobilizing bioactive materials in motive bioreactor systems, said microsponge comprising a porous, biostable, insoluble highly crosslinked collagen matrix containing an inert weighting material, said collagen matrix having an open to the surface pore structure with an average pore size in the range of from about 1 micron to about 150 microns, the pores of said matrix occupying from about 70 to about 98% by volume of the microsponge, said microsponge also having an average particle size of from about 100 to about 1000 microns and a specific gravity above about 1.05 wherein said weighted collagen microsponge is prepared by the steps of
(a) milling a source of collagen selected from the group consisting of Types I, II, and III collagen to produce collagen fibers, (b) admixing said milled collagen with an acidic liquid medium, (c) adding inert weighting material to said acid/collagen mixture, (d) producing droplets of the weighted acid/collagen mixture of step (c), (e) rapidly solidifying said droplets by freezing to form solid particles of a frozen collagen fiber matrix, (f) thermally soaking said solid particles by holding said particles at a temperature at which said particles remain frozen and for a period of time and under conditions sufficient to allow partial agglomeration of said collagen fibers to occur, (g) vacuum drying said solid particles into a dry, porous matrix, and (h) crosslinking the collagen in said dry, porous matrix to produce said weighted collagen microsponge.
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5. A method of preparing a weighted collagen microsponge for immobilizing bioactive materials in motive bioreactor systems, said microsponge comprising a porous, biostable, insoluble highly crosslinked collagen matrix containing an inert weighting material, said collagen matrix having an open to the the surface pore structure with an average pore size in the range of from about 1 micron to about 50 microns, the pores of said matrix occupying from about 70 to about 98% by volume of the microsponge, said microsponge also having an average particle size of from about 100 to about 1000 microns and a specific gravity above about 1.05 wherein said weighted collagen microsponge is prepared by the steps of
(a) milling a source of collagen selected from the group consisting of Types I, II, and III collagen to obtain collagen fibers with a diameter less than 1.0 micron, (b) admixing said milled collagen with an acidic liquid medium, (c) adding inert weighting material to said acid/collagen mixture, (d) producing droplets of the weighted acid/collagen mixture of step (c), (e) rapidly solidifying said droplets by freezing to form solid particles of a frozen collagen fiber matrix, (f) vacuum drying said solid particles into a dry porous matrix, and (g) crosslinking the collagen in said dry, porous matrix to produce said weighted collagen microsponge.
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25. A bioreactor system comprising a plurality of weighted collagen microsponges, wherein said microsponges have been sterilized and aseptically sealed in a reactor vessel and wherein each of said microsponges comprises a porous, biostable, insoluble highly crosslinked collagen matrix containing an inert weighting material, said collagen matrix having an open to the surface pore structure with an average pore size in the range of from about 1 micron to about 150 microns, the pores of said matrix occupying from about 70 to about 98% by volume of the microsponge, said microsponge also having an average particle size of from about 100 to about 1000 microns and a specific gravity above about 1.05,
wherein said weighted collagen microsponges are prepared by a method selected from the group consisting of method 1 and method 2, wherein method 1 comprises the steps of (a) milling a source of collagen selected from the group consisting of Types I, II, and III collagen to produce collagen fibers, (b) admixing said milled collagen with an acidic liquid medium, (c) adding inert weighting material to said acid/collagen mixture, (d) producing droplets of the weighted acid/collagen mixture of step (c), (e) rapidly solidifying said droplets by freezing to form solid particles of a frozen collagen fiber matrix, (f) thermally soaking said solid particles by holding said particles at a temperature at which said particles remain frozen and for a period of time and under conditions sufficient to allow partial agglomeration of said collagen fibers to occur, (g) vacuum drying said solid particles into a dry, porous matrix, and (h) crosslinking the collagen in said dry, porous matrix to produce said weighted collagen microsponge, and wherein method 2 comprises the steps of (a) milling a source of collagen selected from the group consisting of Types I, II, and III collagen to obtain collagen fibers with a diameter less than 1.0 micron, (b) admixing said milled collagen with an acidic liquid medium, (c) adding inert weighting material to said acid/collagen mixture, (d) producing droplets of the weighted acid/collagen mixture of step (c), (e) rapidly solidifying said droplets by freezing to form solid particles of a frozen collagen fiber matrix, (f) vacuum drying said solid particles into a dry, porous matrix, and (g) crosslinking the collagen in said dry, porous matrix to produce said weighted collagen microsponge.
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28. A process for performing a bioreaction comprising
(a) immobilizing a bioactive material in weighted collagen microsponges; -
(b) containing the microsponges having said immobilized bioactive material in a suitable reactor vessel; (c) passing a liquid reagent stream into said reactor in direct contact with said microsponges; (d) agitating the mixture of said microsponges and said reagent stream; and (e) recovering biochemical reaction products from said reactor, wherein each of said microsponges comprises a porous, biostable, insoluble highly crosslinked collagen matrix containing an inert weighting material, said collagen matrix having an open to the surface pore structure with an average pore size in the range of from about 1 micron to about 150 microns, the pores of said matrix occupying from about 70 to about 98% by volume of the microsponge, said micrsponge also having an average particle size of from about 100 to about 1000 microns and a specific gravity above about 1.05, wherein said weighted collagen microsponges are prepared by a method selected from the group consisting of method 1 and method 2, wherein method 1 comprises the steps of (a) milling a source of collagen selected from the group consisting of Types I, II, and III collagen to produce collagen fibers, (b) admixing said milled collagen with an acidic liquid medium, (c) adding inert weighting material to said acid/collagen mixture, (d) producing droplets of the weighted acid/collagen mixture of step (c), (e) rapidly solidifying said droplets by freezing to form solid particles of a frozen collagen fiber matrix, (f) thermally soaking said solid particles by holding said particles at a temperature at which said particles remain frozen and for a period of time and under conditions sufficient to allow partial agglomeration of said collagen fibers to occur, (g) vacuum drying said particles into a dry, porous matrix, and (h) crosslinking the collagen in said dry, porous matrix to produce said weighted collagen microsponge, and wherein method 2 comprises the steps of (a) milling a source of collagen selected from the group consisting of Types I, II, and III collagen to obtain collagen fibers with a diameter less than 1.0 micron, (b) admixing said milled collagen with an acidic liquid medium, (c) adding inert weighting material to said acid/collagen mixture, (d) producing droplets of the weighted acid/collagen mixture of step (c), (e) rapidly solidifying said droplets by freezing to form solid particles of a frozen collagen fiber matrix, (f) vacuum drying said solid particles into a dry porous matrix, and (g) crosslinking the collagen in said dry, porous matrix to produce said weighted collagen microsponge. - View Dependent Claims (29, 30, 31, 32, 33, 34, 35)
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Specification