Fabrication of Chitosan/Polypyrrole-coated poly(L-lactic acid)/Polycaprolactone aligned fibre films for enhancement of neural cell compatibility and neurite growth

Objective Chitosan (CS) and polycaprolactone (PCL) were added into a nerve scaffold of poly(L-lactide acid) (PLLA)/polypyrrole (PPy)-based fibre films to solve the unmatch with the nerve strength and the aseptic inflammation from PLLA. Methods Poly (L-lactide acid)-polycaprolactone (PLLA/PCL) fibre films coated with chitosan (CS) and polypyrrole (PPy) were prepared by electrospinning of aligned PLLA/PCL fibres, electrochemical deposition of PPy nanoparticles and in situ doping of CS in PPy. PC12 cells were electrically stimulated with 100 mV for 2 hours every day via CS/PPy-PLLA/PCL fibre film to promote the neurite growth. Results The surface conductivity and tensile strength of CS/PPy-PLLA/PCL fibre films were 1.03 s/m and 13 MPa, respectively. CS content in fibre films was about 7.5 mg/cm(2), improving the pH value (reached to 5.1) of immersion solution of the fibre film at 16 days. Compared with PPy-PLLA/PCL fibre film, more and longer axons were grown out from PC12 cells cultured on CS/PPy-PLLA/PCL fibre film, indicating the positive effect of CS in fibre film on axon growth. The cell differentiation rate and neurite length on CS/PPy-PLLA/PCL fibre film reached to 38% and 75 mu m, respectively. These results suggest the promotion of electrical stimulation on neurite growth and alignment. Conclusions A synergistic mechanism about the promotion of CS, electrical stimulation and aligned fibres on PC12 cells differentiation, axon outgrowth was proposed. These results indicated the potential application of CS/PPy-PLLA/PCL fibre film in the field of the nerve repair and regeneration.