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The application of tissue engineered patches made of conductive polymer scaffolds combined with cardiomyocytes (CMs) could provide a dual method of improving the damaged myocardium after an infarction: firstly by introducing functional CMs to the area; secondly the conductive polymer could modulate electrical transmission across the scar tissue. Polyaniline (PANI) scaffolds are one such example, however, the consequences of growing CMs on conductive PANI scaffolds with regards to CM electrophysiology are unknown. In this study we assess the hypothesis that conductive PANI scaffolds affect CM calcium transients and action potential morphology in culture. Neonatal rat ventricular myocytes (NRVMs) and neonatal rat fibroblasts were co-cultured on conductive and non-conductive (sodium hydroxide treated) PANI scaffolds and remained viable after four days of culture, covering the surface of the construct. Compared to those cultured on non-conductive PANI scaffolds, NRVM cultured on conductive PANI scaffolds show faster calcium transients, measured using Fluo-4AM and field stimulated at 1 Hz, with a decrease in the time to peak (t p non-conductive=105±6 ms, t p conductive= 85±5 ms, p50 non-conductive=212±12 ms, t 50 conductive= 116±7 ms, p90 non-conductive=404±24 ms, t 90 conductive= 266±15 ms, p

Tissue engineering provides a promising method of introducing functional cardiomyocytes (CMs) to damaged myocardium after myocardial infarction; however, finding a biocompatible construct with the chemical and mechanical properties capable of supporting CM function is challenging. Serum albumin hydrogels are novel autogenic scaffolds with elastic properties that can be tailored to mimic the stiffness of native adult myocardium. We assessed the hypothesis that culturing immature CMs on these serum albumin hydrogels would affect CM gene expression and calcium handling. Neonatal cardiomyocyte (NRVM) viability was maintained for at least 14 days on the hydrogels, with clear sarcomeric striations. Cardiac gene expression was quantified using RT-qPCR and demonstrated an up regulation in many genes of cells cultured on hydrogels compared to glass (e.g. relative expression (log 2-ΔΔCt) of ryanodine receptor 2: glass= -2.3±0.5, hydrogel= -0.3±0.1,pin vivo for cardiac repair.