Buried-Gate MWCNT FET-Based Nanobiosensing Device for Real-Time Detection of CRP

C-reactive protein (CRP), an acute-phase protein synthesized in the liver in response to inflammation, is one of the biomarkers used for the detection of several diseases. Sepsis and cardiovascular diseases are two of the most important diseases for which detection of CRP at very early stages in the clinical range can help avert serious consequences. Here, a CNT-based nanobiosensing system, which is portable and reproducible, is used for label-free, online detection of CRP. The system consists of an aptameric CNT-based field-effect transistor benefiting from a buried gate geometry with Al₂O₃ as a high dielectric layer and can reflect the pro-cytokine concentration. Test results show that the device responds to CRP changes within 8 min, with a limit of detection as low as 150 pM (0.017 mg L^-1). The device was found to have a linear behavior in the range of 0.43-42.86 nM (0.05-5 mg L^-1). The selectivity of the device was tested with TNF-α, IL-6, and BSA, to which the nanosensing system showed no significant response compared with CRP. The device showed good stability for 14 days and was completely reproducible during this period. These findings indicate that the proposed portable system is a potential candidate for CRP measurements in the clinical range.