Effects of Laminin-Coated Carbon Nanotube/Chitosan Fibers on Guided Neurite Growth

This study assesses the ability and potential of carbon nanotube (CNT)/ chitosan to guide axon re-growth after nerve injuries. The CNT/chitosan fibers were produced via the coagulation and hydrodynamic focusing method. Fiber width and morphology were adjusted using such parameters as syringe pumping rate and the coagulant used. The CNT/ chitosan fiber diameters were 50-300 mu m for syringe pumping rates of 6-48 mL/h. Polyethylene glycol/NaOH (25%, w /w) solution was a suitable coagulant for forming fibers with small diameters. Physical property tests demonstrate that the CNT/chitosan composites had superior tensile strength and electrical conductivity compared with those of chitosan alone. The MTT and LDH tests reveal that CNT/ chitosan composites were not cytotoxic. To improve the neural cell affinity of CNT/chitosan fibers, laminin was incorporated onto fiber surfaces via the oxygen plasma technique; cell adhesion ratio increased significantly from 3.5% to 72.2% with this surface modification. Immunofluorescence staining and SEM imaging indicate that PC 12 cells adhered successfully and grew on the laminin (LN)- coated CNT/chitosan films and fibers. Experimental results show that PC12 grown on LN-coated CNT/chitosan fibers in vitro extend longitudinally oriented neurites in a manner similar to that of native peripheral nerves. With the inherent electrical properties of CNTs, oriented CNT/ chitosan fibers have a potential for use as nerve conduits in nerve tissue engineering