Ph sensor and cloud-based monitoring system developed for pressure ulcer monitoring

In this thesis, an IoT-based, integrated, and multifunctional smart dressing system was developed for the monitoring and prevention of pressure ulcers. The system can simultaneously monitor temperature, humidity, pressure, and pH parameters, and wirelessly transmit the resulting data to the Thingspeak platform via the NodeMCU ESP8266 microcontroller. This allows for the dynamic structure of the wound microclimate to be monitored, enabling remote monitoring for healthcare personnel and caregivers, and enabling early assessment of potential infection risks. Furthermore, the system is designed to send instant alarms to responsible parties via the GSM module if temperature and pressure values ​​exceed critical thresholds. One of the most novel contributions of this study is the pH sensor produced in a laboratory environment. The sensor fabrication was achieved by integrating optical lithography, hydrothermal growth, and cyclic voltammetry techniques. The "LIG/ZnO-NTs/PANI" channel structure, consisting of ZnO nanotubes grown via hydrothermal methods on a laser-induced graphene (LIG) layer and a polyaniline (PANI) layer coated via electropolymerization, was able to detect pH changes on the wound surface with high sensitivity. The sensor demonstrated repeatable and highly accurate responses in the pH range of 5–8, demonstrating its reliability with low hysteresis (<3.5 mV) and a high correlation coefficient (R² > 0.995). The high current response obtained at low pH levels was attributed to the direct response of the protonable structure of PANI to H⁺ ions. The large surface area of ​​the ZnO nanotubes and the porous structure of the LIG layer supported the conductivity and stability of the sensor. In conclusion, the developed system offers significant potential in the prevention and management of pressure ulcers through multi-parameter monitoring and a GSM-based early warning mechanism.