Double-Layer Nerve Guide Conduit With Palisade Poly(Lactic-Co-Glycolic Acid) Tube Wrapped by Microporous Chitosan-Collagen Composite

In this study, a double-layer nerve guide conduit (DLNGC) that comprises an inner poly(lactic-co-glycolic acid) (PLGA) scaffold with palisade structure and an outer micro-porous chitosan-collagen composite (CSC) membrane was developed. The PLGA scaffold was fabricated using the commonly used soft-lithography process and then rolled into a tube. The micro-porous CSC membrane was fabricated by lyophilization (freeze-drying), with its pore size being controlled by the chitosan:collagen weight ratio. The CSC properties such as water absorption rate, permeation rate, and biocompatibility were then measured. The CSC containing 25% chitosan (CSC-25%) has a high water absorption and permeation rates. Hence, it was adopted as the outer structure of the developed nerve conduit scaffold. After wrapping a palisade PLGA tube with a CSC-25% membrane to complete a DLNGC, mouse brain neural stem cells KT98 were injected into the inner PLGA scaffold through the pores of the outer CSC membrane. Images of biopsy samples illustrate that KT98 cells can be immobilized on the CSC-25% membrane after seven days’ culture. On the 14th day of culture, the thickness of the KT98 cells was found to have increased, and the cells were wrapped around the PLGA scaffold. The tissue section image further indicated that KT98 cells grew along the palisade structure of the PLGA scaffold.