Effect of Brownian motion on reduced agglomeration of nanostructured metal oxide towards development of efficient cancer biosensor

We report results of the studies relating to fabrication of nanostructured metal oxide (NMO) based cancer biosensor. With the help of 2D electroactive reduced graphene oxide (RGO), we successfully inhibited the Brownian motion of NMO that led to reduced agglomeration of NMO. The nanostructured hafnium oxide (nHfO₂) was used as a model NMO. The reduced agglomeration of nHfO₂ was achieved through controlled hydrothermal synthesis and investigated via nanoparticles tracking analysis (NTA). X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscope (TEM) techniques were used for phase identification as well as morphological analysis of the synthesized nanohybrid (nHfO₂@RGO) material. The 3-aminopropyl triethoxysilane (APTES) was used for the functionalization of nHfO₂@RGO and electrophoretic deposition (EPD) technique was used for its deposition onto ITO coated glass electrode. Further, antibodies of cancer biomarker (anti-CYFRA-21-1) were immobilized via EDC-NHS chemistry and Bovine serum albumin (BSA) was used for blocking of the non-specific binding sites. The electrochemical response studies of fabricated immunoelectrode (BSA/anti-CYFRA-21-1/APTES/nHfO₂@RGO/ITO) revealed higher sensitivity (18.24 µA mL ng⁻¹), wide linear detection range (0 to 30 ng mL⁻¹), with remarkable lower detection limit (0.16 ng mL⁻¹). The obtained results showed good agreement with the concentration of CYFRA-21-1 obtained through enzyme linked immunosorbent assay (ELISA) in saliva samples of oral cancer patients.