Conductive Electrospun Fibers For The Regulation Of Cardiomyocyte And Hepatocyte Behaviors

Electrospinning nanofiber is able to simulate structure of the natural extracellular matrix (ECM), which is beneficial to support growth and form tissues. However, common polymer fibers lack conductivity, which results in insufficient electrical signals to cells, especially for some electrical stimuli-responsive cells. Therefore, multiwalled carbon nanotubes (CNT) are doped into electrospun polymers in the current study. Aligned nanofiber scaffolds with different morphologies and conductivities were fabricated by using the high speed rotating collector. Blend and coaxial composite fibers of CNT and poly(ethylene glycol)-poly(lactic Acid) (PELA) with different conductivities were investigated for cardiomyocyte culture. Similarity, conductive fibers of CNT and poly(styrene-co-maleic acid) (PMSA) were constructed for the study of hepatocyte behaviors.Cardiomyocytes in blend and coaxial conductive fibers grew well, and stretched out into long and narrow cells, which were consistent with orientation of the scaffolds to form aligned organizational diaphragm. On the whole, coaxial conductive scaffolds were better than blend fibers in analysis of the cell viability, migration and protein expression of cardiomyocyte. The results showed that cardiomyocytes spread after 5 days, but did not form a big area and the beating frequency were not synchronized. Cardiomyocyte on scaffolds containing 4-5% CNT were superior to other groups, as well as better cell spreading and protein expression. After culture for 10 days, cells spread out and beat with a synchronized frequency, especially cells in the coaxial fiber containing 4% CNT covered the whole scaffolds, at aspect ratio of 6.5 and a beating frequency of 80 times/min. It was indicated a electric mechanical coupling was good between cardiomyocyte and conductive fibers, which was very important for the study of cardiomyocyte.Hepatocytes adhered each other and gathered to spheroid on PSMA/CNT scaffolds. After culture for 3 days, cells restored the polarity and initated hepatic functions, such as albumin secretion and urea synthesis. After culture for 7 and 15 days, the analysis of morphology and function of cells indicated that hepatocytes on fibers containing 3% CNT almost gathered into spheroid with the size of around 100 um, and the hepatic function were better compared with other scaffolds. Based on this model, the metabolic clearance rate of tolbutamide, S-warfarin, midazolam, testosterone and acetaminophen were determined, and compared with metabolic clearance rate in vivo. Furthermore, rifampicin, glutathione ketoconazole, and probenecid were used as enzyme inducers and inhibitors to examine the acitivities of CYP 3A4 and Ⅱ phase enzymes and the metabolism of testosterone and acetaminophen. Results showed that the model could better maintain the activity of metabolic enzymes, with a correlation coefficient of 0.655 for hepatocytes on fibers containing 3% CNT, and showed responsiveness to inductors and inhibitors, Thus, the hepatocuye culture model was expected to be used for drug screening in vitro.