Control of pore structure and size in freeze-dried collagen sponges.
Because of many suitable properties, collagen sponges are used as an acellular implant or a biomaterial in the field of tissue engineering. Generally, the inner three-dimensional structure of the sponges influences the behavior of cells. To investigate this influence, it is necessary to develop a process to produce sponges with a defined, adjustable, and homogeneous pore structure. Collagen sponges can be produced by freeze-drying of collagen suspensions. The pore structure of the freeze-dried sponges mirrors the ice-crystal morphology after freezing. In industrial production, the collagen suspensions are solidified under time- and space-dependent freezing conditions, resulting in an inhomogeneous pore structure. In this investigation, unidirectional solidification was applied during the freezing process to produce collagen sponges with a homogeneous pore structure. Using this technique the entire sample can be solidified under thermally constant freezing conditions. The ice-crystal morphology and size can be adjusted by varying the solute concentration in the collagen suspension. Collagen sponges with a very uniform and defined pore structure can be produced. Furthermore, the pore size can be adjusted between 20-40 microm. The thickness of the sponges prepared during this research was 10 mm.
Schoof
H
H
Helmholtz-Institute for Biomedical Engineering at the Aachen University of Technology (RWTH), Pauwelsstr. 20, D-52074 Aachen, Germany.
Apel
J
J
Heschel
I
I
Rau
G
G
D001672:Biocompatible Materials / Q000737:chemistry*; D003094:Collagen / Q000737:chemistry*; D005612:Freeze Drying
D001672:Biocompatible Materials; D003094:Collagen