In this study, a portable urea sensor that monitors the urea concentration in flow conditions was fabricated. We propose an electrochemical sensor that continually measures the urea concentration of samples flowing through it at a constant flow rate in real time. For the electrochemical sensing, a porous silk fibroin membrane with immobilized urease was mounted in a polydimethylsiloxane (PDMS) sensor housing. The fabricated urea sensor elicited linear current⁻concentration characteristics in the clinically significant concentration range (0.1⁻20 mM) based on peritoneal dialysis. The sensor maintained the linear current⁻concentration characteristics during operation in flow conditions.
Keywords: amination; flow conditions; real-time monitoring; silk fibroin; urea biosensor.