Part 1.

Recently, conductive polymers have intensively been studied in the field of various bioapplications such as cell therapy, neural regeneration and drug delivery. Among these applications, conductive polymer has exciting potential as scaffolds for tissue engineering. The scaffolds should be open and interconnected structures to allow cells to permit the effective move into the porous structures for mimicking in vivo-like three-dimensional (3D) tissue regeneration. In this study, poly(3,4-ethylenedioxythiophene)-silica (PEDOT-SiO2)andpolypyrrole-silica(PPy-SiO2)compositesare presented to make an 3D conductive porous scaffolds. Two step procedure is adopted to fabricate the conductive 3D scaffolds. First, thehybrid conductive composite layeris formed by vapor phase polymerization (VPP) on a 3D microparticle assembly. Second, microparticles are selectively removed to form a highly porosity skeletal structure. In vitrobiocompatibility studies of the conductive scaffolds are performed by culturing the two kinds of cells (HepG2 and MC3T3-E1 cells) and the cell viability and behavior study was evaluated by scanning electron microscopy (SEM), confocal microscope images and MTT assay. These two conductive scaffolds are effectively capable of cell proliferation in vitrolevel. Our findings are expected that conductive polymer based scaffolds would bea strong candidate for novel scaffolds such as muscle cell, nerve cell culturing for investigating the cell behavior under electrical stimulus

Part 2.

The inherent insolubility and brittleness of poly(3,4-ethylenedioxythiophene) (PEDOT) reduce its processability and practical applicability. Herein, we use in-situvapor phase polymerization (VPP) of 3,4-ethylenedioxythiophene (EDOT) on an oxidant-impregnated thermoplastic polyurethane (TPU) matrix comprising a three-dimensional silica particle assembly to produce a soft, flexible, and conductive TPU-PEDOT hybrid scaffold. The selective removal of silica yielded a highly porous (~95%) skeletal structure, with the effective penetration, diffusion, and polymerization of EDOT resulting in uniform PEDOT formation both on the surface and on the inside of the TPU matrix. The mechanical and electrical properties of the obtained scaffold were probed by bending, compression testing, and stress-strain and electrical measurements. The electricalresistance of the scaffold equaled 17 kΩ and did not change after ~500-fold bending, whereas the observed elastic modulus was much lower (300 kPa) than that of TPU (3.3 MPa). In vitrobiocompatibility was investigated by MC3T3-E1 cell culturing, with cell viability evaluated using the WST assay, and cell morphology examined by confocal microscopy. Thus, the soft and flexible TPU-PEDOT hybrid scaffold produced by VPP might be practically useful, implying that this preliminary investigation needs to be extended to study the behavior of muscle and nerve cells under electrical stimulation.

Part 3.

Soft foam using a gas foaming method is composed of a flexible polyurethane foam and polyether urethane group of the urea portion is associated with the successive groups arranged in the reaction of the polyol and isocynate. Flexible foam polyurethane foam has a porous structure and has excellent restoring force. The production process simple, and to prepare a polyurethane foam having an excellent restoring force there is no problem of the porogen residue forming the porosity of the structure and flexibility by giving the conductivity by the VPP, and proposes a method for producing a conductive scaffold flexible. Recently, cell migration has been studied as a factor affecting cell maturation. The density or resulting the in vitro biocompatibility of the scaffold produced by given the mobility of the cells and mature cells, using the orientation of the pore shape of the scaffold in using a fine pattern this study as a way to impart mobility to the cell of the protein MC3T3-E1 preosteoblast.The electrical performance was also confirmed that this can to a certain growing resistance when strain was applied to the scaffold decreases be useful for the electrode and the strain sensor.