Contactless and Wireless Wound Monitoring Using Nitrogen-Doped Graphene Antenna Sensor

Quantitative remote wound monitoring has the potential to shorten patient recovery time and alleviate the workload of healthcare professionals. In this study, a nitrogen-doped horizontally grown graphene (NHG) antenna sensor with a working frequency of 2.45 GHz was designed for wireless real-time monitoring of wounds. The sensor comprises 32 NHG microtubes (1 mm in diameter), a porous Cu radiation electrode, a polydimethylsiloxane substrate with a cylindrical channel array, and a Cu ground plane. Its novel structure enables body fluid and its temperature and pH value sensing by tracking dual signals, such as resonance frequency and return loss, thereby facilitating the identification of living organisms and real-time quantitative wound assessment. Notably, the NHG microtubes, which penetrate the Cu electrode and PDMS substrate, regulate the radiofrequency radiation field and enhance the monitoring sensitivity. The sensor exhibits a minimum fluid response volume of 25 μL, a temperature detection range of 34-43 °C, a resolution of 0.1 °C, and a response time of 20 s. Furthermore, the NHG antenna sensor reliably evaluated the pH value, volume, and area of the wound using a machine learning algorithm. The system was successfully validated for real-time monitoring of wound healing in mice and has been preliminarily applied to monitor wounds of various sizes and locations in human patients.