Chondroitin sulfate-AuNRs electroactive scaffolds for on-demand release of biofactors.

Controlled release systems are often integrated into polymeric scaffolds to supply essential biofactors to trigger physiological processes in engineered tissues. Here, we report the modification of chondroitin sulfate (CS) electroactive polymer with gold nanorods (AuNRs) to create hybrid macroporous scaffolds for enhanced on-demand release of growth factors and cytokines. The mechanical properties, porosity and degradation of the hybrid scaffolds were evaluated, and the viability and functionality of seeded cardiac cells were assessed. Following, the ability to control the release of the enzyme lysozyme, and the cytokine, stromal cell-derived factor 1 (SDF-1) by applying electrical stimulation, was demonstrated. The AuNRs were able to increase the current through the scaffolds, providing an efficient on-off release profile of SDF-1, which resulted in higher migration of cells expressing CXCR4 receptor. Finally, the engineered scaffolds were transplanted in rats and SDF-1 was released daily by electrical stimulation, promoting blood vessel-forming cell infiltration and vascularization. We envision that gold nanoparticles and other conducting nanomaterials can be incorporated into different electroactive materials to improve their capabilities not only for tissue engineering applications, but for a variety of biomedical applications, where enhanced electrical stimulation is needed.