Laser-Printed Highly Sensitive Flexible Urea Sensors

Real-time kidney function monitoring is possible with a wearable urea sensor, which continuously detects urea concentration in body fluid. Wearable devices require the urea sensor's sensitivity and versatility. Scalable device fabrication requires a simple and fast fabrication routine. In enzyme-based urea sensors, urease is too big compared to urea, causing steric hindrance and low sensitivity. Urease is temperature-sensitive and has severe storage conditions, making it unsuitable for wearable devices. Here, we fabricate a novel type of urea sensor using laser-induced forward transfer printing. This sensor is fabricated by laser-induced forward transfer to deposit sensing elements containing nickel and uses N afion to pack sensing elements, realizing high sensitivity towards urea detection. Also, this sensor can achieve good flexibility due to the carbon cloth substrate and can be rapidly fabricated on a large scale with laser printing. This work will generate newfound insight into printed flexible electrodes for wearable urea detection applications.