DEVELOPMENT OF CONDUCTIVE FILM INCORPORATED WITH PHOTOTHERMAL NANOPARTICLES FOR CONTROLLED AND ACCELERATED NEURAL STEM CELLS DIFFERENTIATION
Keui-Yu Chao1, Tzu-Wei Wang2
1Institute of Biomedical Engineering, Taiwan; 2Department of Materials Science and Engineering, Taiwan
In central nervous system, a mechanically obstructive glial scar tend to walling off areas of damage to protect the fragile brain tissue after injuries. However, the construction of the scar and the production of inhibitory molecules by astrocytes are contributing factors for regenerative failure. Transplantation of stem cells or mobilization of endogenous stem cells within the injury site, have been suggested as a potential therapies for CNS injuries. Yet, being able to control the proliferation and differentiation of stem cells into specific cellular phenotypes and to prevent tumour formation still remain challenges. In this study, an electrical conductive film composed of oxidative polymerized carboxyl-capped aniline pentamer (CCAP) and ring-opening polymerized tetra poly(D, L-lactide) (4a-PDLLA) was designed. In addition, nanoparticles based on polyaniline (PAni) and polyoxyethylene-stearate were embedded in the film as a photothermal (PT) agent. This conductive film was suggested to act as a substrate for endogenous electric fields transmission in tissue, resulting in the improvement of tissue regeneration. To accelerate the regeneration process, the PAni nanoparticles triggered by near-infrared were used as a heat source to create a mild heat environment. In the results of 1H NMR, CCAP and 4a-PDLLA were successfully prepared and characterized. The coupling of CCAP and 4a-PDLLA was confirmed by FT-IR. According to cyclic voltammetry and UV-visible spectrum, the transition between different oxidation state and doping/ dedoping process of CCAP were achieved. PAni NPs showed excellent photothermal conversion efficiency under NIR with wavelength of 808 nm. In order to differentiate hNSCs into neurons, the cell response to electrical and thermal stimulus will be demonstrated.