Eight-channel vertical-graphene antenna immunosensor array for rapid detection of CYFRA 21-1 in human serum

Multichannel rapid-detection systems are efficient tools for performing multiple blood-sample tests and detecting multiple tumor markers. In this study, we developed a multiplex immunoassay system comprised of eight Au-vertical graphene (VG)-based antenna sensors connected to a multichannel radiofrequency (RF) switch. The Au-VG layer loaded with antibodies and BSA was immunologically bound to the cytokeratin 19 fragment 21-1 (CYFRA21-1) antigen and simultaneously transmitted RF signals. The 2.45 GHz antenna sensor rapidly self-incubated tumor markers owing to microwave thermal effects, while the sensor array maintained a temperature of 37 °C with the assistance of a temperature controller. The response times for the single sensor and the eight-channel array were 2 and 5 min, respectively. For the detection of CYFRA21-1, a wide linear dynamic range was achieved (0.1-12000 pg mL^-1), with a detection limit as low as 35.12 fg mL^-1. The sensor array system is capable of simultaneously measuring the CYFRA21-1 concentration in eight serum samples or eight tumor markers in a drop of finger blood with high sensitivity and speed, making these immunosensors practical for the rapid and reliable screening of early-stage tumors.