Biocompatibility of NGF-grafted GTG membranes for peripheral nerve repair using cultured schwann cells

We previously developed a biodegradable and biocompatible composite composed by β-tricalcium phosphate ( β-TCP) and gluataraldehyde cross-linking gelatin (GTG) with good mechanical property feasible for surgical manipulation. The purpose of this study was to evaluate the feasibility of immobilizing nerve growth factor (NGF) onto the GTG membranes with carbodiimide. Besides NGF, we also tried to culture Schwann cells on our composite membrane. Membranes for this experiment were divided into four groups for Schwann cell culture (n=18): (1) GTG membrane grafted with NGF (GEN) (2) GTG membrane soaked in 50 ng/ml NGF solution for 24 hrs (GN) (3) blank GTG composite membrane (GTG) (4) Petri dish as control group. The result of lactate dehydrogenase (LDH) study did not show significant difference among GTG, GEN, GN and control group. This indicated that GTG composite, whether cross-linked with NGF or not, has little cytotoxic effect. Comparing the protein content and MTT assay among GEN, GN composite and control group, the data confirmed more attachment of Schwann cells on the GEN composite. This technique we used in this study-provided a method to fabricate a novel biomaterial incorporation of Schwann cells and permitting long term release of NGF.