Flexible wound healing system for pro-regeneration, temperature monitoring and infection early warning.

To break the "Black-Box" status of the wound healing process under traditional dressing, which cannot achieve satisfactory repair outcome of skin wounds, a wound healing system with the abilities of pro-regeneration and real-time monitoring of wound status has become a considerable necessity. Here, by integrating the emerging bioelectronics and software, we created a flexible wound healing system. The hardware system was designed as Band-Aid shaped with a double-layer structure; the upper is the flexible temperature-sensing layer comprising the temperature sensor STH21, power manager circuit and data processing circuit, and the lower is a collagen-chitosan dermal equivalent for skin regeneration. A customized software application (app) installed on a smartphone to receive data from the sensing layer by BLE4.0 can display and analyze real-time wound temperature. Our system had high monitoring sensitivity and stability, good stretchability, excellent reliability and biocompatibility. It was applied to a pig skin wound model to reveal temperature fluctuation during the entire wound regeneration process. As a credible reference and foundation for further early warning of an adverse event, three main phases of temperature fluctuation were found: the rising phase (below 39 °C), plateau phase (39-39.5 °C), and falling phase (below 39 °C), which were accompanied by significant wound biological events, including inflammatory cell infiltration, angiogenesis and wound healing. Furthermore, verified by wound infection models of different healing phases and wound Gram's staining, early warning ahead of serious infection was realized with the use of a customized app's alarm.