Photothermally tunable biodegradation of implantable triboelectric nanogenerators for tissue repairing

Implantable triboelectric nanogenerators (iTENGs) are promising to work as sustainable power source for implanted healthcare electronic devices. In this study, we fabricated a serial of biodegradable (BD) iTENGs and effectively tuned their degradation process in vivo by employing Au nanorods (AuNRs), which responded to the near-infrared (NIR) light sensitively. The implanted BD-iTENG worked well for more than 28 days in vivo, without NIR treatment. When NIR treatment was applied, the output of AuNRs-BD-iTENG rapidly reduced to 0 within 24 h and the device was mostly degraded in 14 days. This showed that the in vivo degradation of our BD-iTENG could be triggered and come into effect very quickly with rational manipulation. The peak value of in vitro and in vivo output voltage generated by the AuNRs-BD-iTENG were 28 V and 2 V, respectively. Moreover, the in vivo output voltage was applied on fibroblast cells and demonstrated a significant acceleration for cell migration across the scratch, which was very beneficial to wound healing process. In addition, we discovered that the alternating BD-iTENG output was as efficient as direct current (DC) stimuli. The mechanisms were investigated. Our work has demonstrated the feasibility of building a photothermally tunable BD-iTENG as a transient power source for biomedical healthcare electronics.