Selective detection of biotinylated IL-6R protein using both CVD and epitaxial graphene-based electrochemical sensor and its reusability

Here, we report the selective detection of biotinylated interleukin-6 receptor (IL-6R) protein using both chemical vapor deposition (CVD) and epitaxial graphene (EG) based electrochemical sensors and their reusability. Detection was based on the principle of avidin-biotin technology, which was widely used in different types of sensor technology. Following the characterization of graphene, the CVD and EG on SiC were fabricated with gold nanoparticles using our recently developed technique. The CVD graphene-based device was made by transferring the CVD graphene onto an interdigitated array electrode (IDA). In contrast, the EG-based device was made by photolithography by fabricating interdigital electrodes on EG on SiC. The detection of IL-6R was monitored by real-time two-terminal current measurements at fixed voltages, while the IL-6R protein was injected into avidin-immobilized graphene-based devices. Drops of the current (Ids) upon injection of as low as 50 pg/ml of IL-6R solution confirm the detection of IL-6R with ultra-high sensitivity. The specificity of the device was confirmed by a chicken egg white solution in PBS, which contains a variety of biomolecules. The EG on a SiC-based device can also be used to detect biomolecules with high sensitivity. The EG on the SiC-based device was found to be reusable after the physical cleaning procedure. The present study is expected to be exploited in the development of reusable ultra-sensitive point-of-care biosensors.