Hyaluronic Acid - Collagen Copolymer Hydrogels As The Frame Material Of The Central Nervous Tissue Engineering Research

Hyaluronic acid (HA) is a naturally-occurring linear polysaccharide comprised of β-1, 4-linked D-glucuronic acid (β-1, 3) N-acetyl-D-glucosamine disaccharide units, and it locates universally in extracellular matrix of animal and human beings. As to its low immunity, hyaluronic acid is an excellent biomaterial for tissue engineering. Collagen protein is one of the main structural proteins with high mechanical properties of extracellular matrix which support many kinds of tissue growth. In this paper, hyaluronic acid and collagen protein were cross-linked together and a porous hydrogel was developed for central nervous system (CNS) tissue engineering.The morphology, porosity and pore diameter distribution were studied by SEM and Mercury Intrusion Instrument respectively. The biodegradability was also evaluated in vitro. To evaluate the biocompatibility of HA-Collagen hydrogel combined with cultured fetal brain cell of rat, provide some clue for the choice of biomaterial in neural tissue engineering. MN9D, dorsal root ganglion and fetal brain cells were cultured respectively combined with biomaterials in vitro, and the morphological characters were detected with light microscope and scanning electronic microscope and laser confocal system. Fetal brain cells could be attached to and extended on HA-Collagen hydrogel and grew normally. HA-Collagen hydrogel could stimulate the growth of the cells. The hydrogel was also primarily evaluated in a cortex injury model in adult rat.The composite hydrogel have good elastic properties and low toxic to cells. Further more, it is degradable in vivo with safety. HA and collagen are all biocompatible polymers and the composite hydrogel should not be repelled by host tissue and is suitable to be implanted into human body. The HA-Collagen hydrogel provides a microenvironment for the attachment, proliferation and division of cell, which is beneficial to nutrition transport and metabolism of tissue during the course of regeneration. The results showed that HA-Collagen hydrogel have good biocompatibility with brain cells and is a promising biomaterial for cell transplantation in neural tissue engineering.