Preparation Of Polypyrrole And Its Composite Materials For Stem Cell Culture Research

The combination of the synthetic analogs of the extracellular matrix (ECM)and stem cell culturing is a potential solution for morden tissue engineering.Electrical stimulation was found to influence tissue regenaration and stem celldifferentiation. Due to its outstanding biocompatibility, Polypyrrole (PPy) is ahopeful candidate to couple electrical stimulation and stem cell growth. Toimprove PPy’s poor mechanical properties, it is promissing to combine PPy withfine-machinable polylactic acid (PLA).In this work, human umbilical cord mesenchymal stem cell (hUCMSC)were cultured on the electrochemical synthesized PPy film (conductivity13S/cm) with or without electric simulation. The secretion of NGF was measuredto increase with electric simulation. A high current density resulted from itshigh conductivity was found to be adverse to the adhesion of cell. Meanwhile, itwas found that the conductivity of PPy films deteriorated with the influence ofcell, current and media.PPy nanotubes, whose conductivity reached100～101S/cm when they werepressed into pellets, was synthetized via soft-template method. PPy/PLAcomposite film were prepared through liquid mixing and direct casting. Theconductivity of the film is10-3S/cm with only5wt%PPy blended in PLAmatrix. The conductivity of composite films maintained about80%in5days’incubation with current, demonstrating a fine electrical conductivity stability.PPy nanotubes were embedded into PLA electrospinning fibers instead ofthe popular in-situ polymerization and coating method in order to avoid losingconductivity in media. The effects of solvents, PLA concentrations and PPyadditives on the morphology of electrospun products were studied. In presentelectrospinning systems, samples with high concentration of PLA and high ratioof dichloromethane (DCM) in solvent are the optimal solution for embeddingPPy nanotube into PLA fiber.