Optimizing Electrical Stimulation Parameters to Enhance Viability of Dental Pulp Stem Cells in Graphene-Based Scaffolds

Abstract

Tissue engineering (TE) combines cells, biomaterials, and external regulatory cues to support tissue repair and regeneration. Graphene-based scaffolds are promising TE platforms because they combine electrical conductivity, mechanical reinforcement, and cytocompatible surface properties. When paired with electrical stimulation (ES), these scaffolds may provide an electroactive microenvironment that influences stem cell behavior. However, suitable ES conditions for dental pulp stem cells (DPSCs) cultured on graphene-based scaffolds remain insufficiently defined. This study examined how different electric field (EF) intensities affect DPSC viability and cytotoxicity on graphene oxide/sodium alginate (GOSA) and reduced graphene oxide/sodium alginate (rGOSA) scaffolds. Three-dimensional scaffolds were prepared by freeze-drying, coated with poly-l-lysine (PLL), seeded with DPSCs, and stimulated using a custom Ti mesh electrode bioreactor. EF intensities from 0 to 500 mV mm–1 were applied for 1 h/day over three consecutive days. Cell responses were evaluated using Trypan Blue, Alamar Blue (AB), and lactate dehydrogenase (LDH) assays. Moderate EF intensities, particularly 50–100 mV mm–1, improved cell viability and reduced cytotoxicity, with the strongest response observed in rGOSA scaffolds. In contrast, higher EF intensities of 250–500 mV mm–1 reduced viability and increased cytotoxicity. These findings indicate that scaffold conductivity and ES intensity are key determinants of DPSC response and support the use of rGOSA scaffolds with moderate ES for TE applications.