Harnessing Bioscaffold-Coupled Stimulation Through Electroactive Graphene Foam for Enhanced Cellular and Mechanical Responses

Abstract

Osteoarthritis is a leading cause of joint degeneration, with limited treatment options that fail to restore native cartilage. Tissue engineering offers a promising strategy by combining cells, scaffolds, and bioactive cues to regenerate functional tissue, though challenges remain in developing systems that integrate and precisely control these signals in three-dimensional environments. This work establishes a scaffold-coupled electrical stimulation (ES) platform using electroactive graphene foam (GF) to modulate cellular and mechanical responses relevant to cartilage tissue engineering. Custom stereolithography-printed bioreactors were developed to deliver low-voltage biphasic square waves (20–60 mVpp, 1 kHz) directly to GF scaffolds under submerged culture, maintaining waveform fidelity and cytocompatibility (>90% viability). ATDC5 chondroprogenitor cells exhibited strong attachment and infiltration within the opaque 3D scaffold, visualized using a correlative imaging workflow combining fluorescence, SEM, and X-ray micro-CT. ES induced up to a 230% increase in calcium fluorescence intensity, and proteomic analysis revealed voltage-dependent shifts in ECM, cytoskeletal, and signaling protein expression. These molecular differences coincided with enhanced mechanical performance, with stimulated composites showing up to a ~25% increase in equilibrium modulus and 65.6% greater energy dissipation under cyclic compression at 60 mVpp. This integrated system offers a tunable platform for delivering and studying direct ES in vitro and provides new insights into the mechanistic effects of electrical cues on chondroprogenitor behavior.