Conducting cryogel scaffold as a potential biomaterial for cell stimulation and proliferation

The aim of the study was to demonstrate the potential of the cryogelation technique for the synthesis of the conducting cryogel scaffolds which would encompass the advantages of the cryogel matrix, like the mechanical strength and interconnected porous network as well as the conductive properties of the incorporated conducting polymeric material, polypyrrole. The cryogels were synthesized using different combinations of oxidizing agents and surfactants like, sodium dodecyl sulfate (SDS)/ammonium persulfate (APS), SDS/iron chloride (FeCl3), cetyl trimethyl ammonium bromide (CTAB)/APS, and CTAB/FeCl3. The synthesized gels were characterized by scanning electron microscopic analysis for morphology, Fourier transform infrared spectroscopy for analyzing the presence of the polypyrrole (0.5–4 %) as nano-fillers in the gel. It was observed that the presence of these nano-fillers increased the swelling ratio by approximately 50 %. The synthesized conducting cryogels displayed high stress bearing capacity without being deformed as analysed by rheological measurements. The degradation studies showed 12–15 % degradation in 4 weeks time. In vitro studies with conducting and non-conducting cryogel scaffold were carried out to optimize the stimulation conditions for the two cell lines, neuro2a and cardiac muscle C2C12. 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay showed approximately 25 and 15 % increase in the cell proliferation rate for neuro2a and C2C12 cell line, respectively. This was observed at a specific voltage of 100 mV and 2 V, for a specified duration of 2 h and 1 min, respectively for the conducting scaffold as compared to the control. This can play an important role in tissue engineering applications for cell lines where acquiring a high cell number and functionality is desired.