PHEMA/PPy cytocompatible conductive cryogels: One-pot synthesis, characterization, and electrical properties

Conductive cryogels have gained significant research interest in recent years due to their potential biomedical applications such as implantable and wearable devices, biosensors, medical patches, health recording electrodes, drug delivery systems, bioactuators, etc. In this study, poly(2-hydroxyethy methacrylate)/polypyrrole (PHEMA/PPy) cryogel possessing macroporous morphology, conductivity, cytocompatibility, and mechanical compression properties were produced by cryopolymerization in the presence of excess ammonium persulfate. Electrical properties of the PHEMA and PHEMA/PPy cryogels as a function of frequency were compared using electrical impedance spectroscopy. At low frequencies, the real part of the dielectric constant of the PHEMA was found to be about 4-fold higher than that of the PHEMA/PPy whereas the average imaginary dielectric constant of PHEMA/PPy cryogels was observed to be nearly 6-fold higher than that of the PHEMA cryogels at the same frequency region. This behavior suggests that the addition of polypyrrole to the PHEMA cryogel increases the conductivity of the resultant material. This claim is further supported by comparing the results of the loss tangent, impedance and AC conductivity variations as a function of frequency for all samples. According to cytotoxicity, morphological, and AO/EB staining studies. PHEMA/PPy cryogel did not cause any toxic effect on L929 cells, except for PHEMA/PPy4 extract. These data suggested that the PHEMA/PPy cryogel with conductivity and cytocompatibility is a promising candidate in biotechnology and biomedical engineering.