The impact of electrical stimulation protocols on neuronal cell survival and proliferation using cell-laden GelMA/graphene oxide hydrogels

The development of electroactive cell-laden hydrogels (bioscaffolds) has gained interest in neural tissue engineering research due to their inherent electrical properties that can induce the regulation of cell behaviour. Hydrogels combined with electrically conducting materials can respond to external applied electric fields, where these stimuli can promote electro-responsive cell growth and proliferation. A successful neural interface for electrical stimulation should present the desired stable electrical properties, such as high conductivity, low impedance, increased charge storage capacity and similar mechanical properties related to a target neural tissue. We report how different electrical stimulation protocols can impact neuronal cells' survival and proliferation when using cell-laden GelMA/GO hydrogels. The rat pheochromocytoma cell line, PC12s encapsulated into hydrogels showed an increased proliferation behaviour with increasing current amplitudes applied. Furthermore, the presence of GO in GelMA hydrogels enhanced the metabolic activity and DNA content of PC12s compared with GelMA alone. Similarly, hydrogels provided survival of encapsulated cells at higher current amplitudes when compared to cells seeded onto ITO flat surfaces, which expressed significant cell death at a current amplitude of 2.50 mA. Our findings provide new rational choices for electroactive hydrogels and electrical stimulation with broad potential applications in neural tissue engineering research.