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

Abstract

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 μm, 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.

Axonal extension from dorsal root ganglia on fibrillar and highly aligned poly(lactic acid)-polypyrrole substrates obtained by two different techniques: Electrospun nanofibres and extruded microfibres

“…Therefore, it is of great importance to study the topography of the substrates in order to direct axonal growth towards a target through the mechanical constriction of cells [13,14]. Many studies have concluded that a substrate based on aligned fibres is capable of guiding axonal growth, whereas in a flat substrate such as a glass cover or a substrate with randomly oriented fibres, axons grow unoriented [13][14][15][16][17][18]. Besides the relevance of having an aligned substrate, the size of the fibres that form the substrate is also critical.…”

Electro-responsive polymer-based platforms for electrostimulation of cells

“…Thus, it properly deliveries electrical signals to cells and provides a suitable environment to accommodate cells and support their metabolic activities promptly. 1,5,[59][60][61][62] Several electro-responsive polymers are used in the development of advanced conductive cell culture/tissue engineering scaffolds, including those from the conjugated polymer family poly(pyrrole) (PPy), [63][64][65][66] polyaniline (PANI), [67][68][69][70][71] poly(3,4-ethylene dioxythiophene) (PEDOT)), [72][73][74][75] and polysaccharides (chitosan (CS)), [76][77][78][79][80][81][82] hyaluronic acid (HA), 83 and alginate (ALG). 84,85 Conductive scaffolds are also commonly obtained by combining highly conductive carbon-based materials (e.g., carbon nanotubes (CNTs), [86][87][88][89] multiwalled carbon nanotubes (MWCNTs), 79,90,91 graphene (GR), [92][93][94] graphene oxide (GO) 95 and reduced graphene oxide (rGO)) 96,97 with non-conductive polymers such as poly(lactic acid) (PLA), poly(-caprolactone) (PCL), poly(ethylene glycol) (PEG), collagen and its derivatives.…”

3D Electrospun Synthetic Extracellular Matrix for Tissue Regeneration

“…[73a] Through a combination of bioactive cues, aligned topographies, conductive coating, and ES, CS/PPy-coated poly(L-lactic acid) (PLLA)/PCL fiber films with 100 mV of ES were found to enhance neural cell compatibility and neurite growth. [97] In vivo, the implantation of aligned conductive electrospun scaffolds in rats after spinal cord injury improved functional recovery and electrical signals measured as motorevoked potentials. [98] Thus, multicue scaffolds may hold great potential for application in neural tissue regeneration.…”