Core–Shell Biocompatible Piezoelectric Nanocomposite with Enhanced Cell Adhesion for Potential Biomedical Applications

Flexible piezoelectric devices for biomedical applications often encounter a crucial balance between performance and biocompatibility. In this study, we introduce a core-shell approach to address this issue. A high-performance piezoelectric core, made of Rochelle salt embedded in a cytotoxic Ecoflex 00-30 matrix, was fully encapsulated by a multifunctional, biocompatible shell. This PDMS coating, reinforced with silanized cellulose nanofibers (Si-CNF), was surface-treated with cellulose nanofibers to actively support cell adhesion. The coating not only made the device nontoxic but also significantly improved its performance: the maximum output voltage increased by 163% (to 156.8 mV), and the elastic modulus nearly doubled (to 1.286 kPa). Additionally, the functionalized surface promoted HeLa cell adhesion comparable to standard culture substrates (<i>p</i> > 0.05). Our work demonstrates a successful design that eliminates the toxicity of core materials while enhancing electromechanical output, paving the way for safer, more effective implantable energy-harvesting devices.