Biocompatibility is an important property of materials intended for bioelectronic and tissue engineering applications. The cytocompatibility of the TR-CP was assessed using the modified ISO 10993-5 protocol (SI Section 3.8, 3.9). In addition to the pristine TR-CP, we also studied the cytocompatibility of TR-CP/alginate composites as a permanently crosslinked network would allow for more control in experiments (no need to constantly maintain T > LCST) and would allow for reliable gel identification in the in vivo studies. For these studies, we adjusted the TR-CP to a neutral pH. Characterization of the rheological (Fig. ) and electronic properties (Fig. , Tables S6-S7) show that the TR-CP behaves similarly under this pH and retains its sol-gel transition when reconstituted in cell media (Fig. ).