Next, a direct contact in vitro assay was performed (Fig. ) by suspending L929 fibroblasts in a media-reconstituted TR-CP dispersion before gelling. Collagen was used as a control and ethanol-treated collagen was used as a positive control. We saw high cell viability (> 95%, Fig. ) in the TR-CP gel (Fig. ). The control displayed larger cell spreading (Fig. ), potentially due to the stable gelation and structural integrity of the collagen, whereas cell culture in the pure 3.6% TR-CP resulted in less cell adhesion and spreading due to fluctuations in temperature during cell staining procedures (Fig. ). In preparation for in vivo studies, he TR-CPs were then incorporated into alginate precursor and subsequently chemically crosslinked, to form a permanently crosslinked TR-CP/alginate composite (Fig. , Fig. ). Direct contact viability was tested for TR-CP/alginate with two loadings of TR-CP in the composite (3.6 wt% and 5.6 wt%). Alginate treated with ethanol was used as a positive control (Fig. ). At both concentrations, no significant difference in cell viability was observed (Fig. ) between the control alginate gel (Fig. ) and TR-CP/alginate gels (> 95%, Fig. and Fig. ). The positive cell outcomes of the TR-CP are consistent with prior reports of PEDOT:PSS composites containing PNIPAM, and confirm the high in vitro cytocompatibility of the TR-CP. The rheological and electronic properties of TR-CP/alginate are summarized in Fig. . The samples and their controls for cytocompatibility are listed in Table . To test the in vivo cytocompatibility of the TR-CP, permanently crosslinked 5.6 wt% TR-CP/alginate composite gels and control alginate gels were implanted subcutaneously into Sprague Dawley rats (Fig. ). The gels were explanted at 1-and 2-weeks post implantation to check for acute inflammatory response. At both time points, the rats showed no signs of distress, and the wound sites did not exhibit any signs of infection or hematoma. In both treatment groups, H&E staining revealed the intact gels surrounded by a layer of fascia residing beneath the muscle layer observed, an increased inflammatory response is common when conducting polymers are implanted. There were also signs of cell infiltration to the site of the gel, indicated by the presence of microvasculature in the surrounding tissue (Fig. ). Despite the increased cellular activity, the TR-CP did not cause any necrosis in the local skin environment. This study suggests the TR-CP/alginate composite gels have minimal negative effects to the overall tissue function,