An Ultrasensitive Electrochemical Immunosensor Comprising Green Synthesized α-Fe₂O₃NPs_rGO Nanocomposite for Determination of Oral Cancer

Oral squamous cell carcinoma is a commonly known malignant tumor in the maxillofacial and oral region with a poor prognosis. Therefore, in the present letter, we have developed for the first-time screen-printed electrode (SPE)-based affordable, simple, and ultrasensitive electrochemical immunosensor using a green synthesized hematite nanoparticles (α-Fe2O3NPs) supported on reduced graphene oxide (rGO) nanocomposite for determination of CYFRA-21-1 cancer biomarker. The α-Fe2O3NPs_rGO composite has been prepared using a green method employing the leaves extract of Cinnamomum tamala. The 3-aminopropyl triethoxysilane (APTES) helped in the functionalization of α-Fe2O3NPs_rGO nanocomposite and was drop casted to the working area of SPE, followed by immobilization with the anti-CYFRA-21-1 antibodies as well as bovine serum albumin (BSA) to form BSA/anti-CYFRA-21-1/APTES/α-Fe2O3NPs_rGO/SPE immunoplatform. The α-Fe2O3NPs_rGO nanocomposite was characterized by utilizing the Fourier transform infrared spectroscopy, X-ray diffraction, differential pulse voltammetry, and cyclic voltammetry for investigating the crystal structure, as well as electrochemical properties. The developed immunosensor depicted remarkable electrochemical properties having broad linearity (0.5–20 ng/mL), limit of quantification of 0.048 ng/mL, low detection limit of 0.014 ng/mL, and high sensitivity of 90.42 µA (log (ng/mL)−1 cm−2. In addition, it showed high reproducibility and good selectivity towards the CYFRA-21-1 biomarker. Thus, this letter unlocks innovative prospects for exploring the electrochemical behavior of green synthesized α-Fe2O3NPs_rGO and its efficacy for fabricating electrochemical biosensors, as well as point of care sensing devices.