A CSRR-IDC-Based Microwave Biosensor for Non-invasive Creatinine Detection

Rapid detection of creatinine level is significant for the diagnosis of renal dysfunction. Conventional methods used for creatinine detection are not portable and cannot provide real-time results. This letter describes the design and validation of a microwave biosensor to overcome these limitations. The resonator is designed using a complementary split-ring resonator and an interdigitated capacitor fabricated on an FR-4 substrate of dimensions 50 × 25 mm2. Simulations showed a resonance frequency of 2.013 GHz, while measurement results yielded a resonance of 1.941 GHz, with a deviation of 72 MHz. The fabricated device was tested with 10-μL creatinine samples of 0.8-2.0 mg/dL, which are within the physiological range. A sensitivity of 0.77% is achieved for the detection of concentration change in chemical solutions. These results show the capability of the biosensor for real-time biomedical diagnosis.