Wearable Biosensors for Monitoring Wound Healing

Abstract

Continuous health monitoring often requires hospitalization, which can become an expensive and inconvenient choice for the patient. In this perspective, wearable sensors that allow in situ biosensing constitute a very promising technology. This work aims to develop immunosensors for continuous monitoring of the wound healing process, based on pH changes, as well as on the concentrations of inflammatory proteins such as the C-reactive protein (CRP). Sensing principles include the use of responsive hydrogels that swell in response to changes in the surroundings, and the use of functional surfaces that specifically recognize the target protein. The detection principle is based on an optical signal, using the evanescent field of light propagating along a waveguide, probing refractive index changes. An optical sensing system that can be integrated in a wound dressing patch has been designed, including a white light source (LED), and a spectrometer for detection. The sensor was successfully tested in the laboratory with biological samples (blood serum), demonstrating reversible pH measurements between pH 6-8, and detection of changes in the concentration of CRP between 1 and 100 μg/ml. The sensor will later be integrated into wound dressings or bandages, forming a sensing patch that is connected via optical fibres and electrical wires to the detection system and power supply. This novel technology will be particularly valuable in applications such as the supervision of skin grafts and ulcer treatments.