Electrochemical Detection of Vibrio cholerae by Amine Functionalized Biocompatible Gadolinium Oxide Nanoparticles

Herein, we report the biocompatible amine-functionalized gadolinium oxide nanoparticles (Gd₂O₃ NPs) for the possibility of electrochemical detection of Vibrio cholerae (Vc) cells. The microwave irradiation process is applied to synthesize Gd₂O₃ NPs. The amine (NH₂) functionalization is carried out via overnight stirring with 3(Aminopropyl)triethoxysilane (APTES) at 55 °C. The size of NPs amine functionalized APETS@Gd₂O₃ NPs are determined by transmission electron microscopy (TEM). APETS@Gd₂O₃ NPs are further electrophoretically deposited onto indium tin oxide (ITO) coated glass substrate to obtain working electrode surface. The monoclonal antibodies (anti-CT) specific to cholera toxin associated to Vc cells are covalently immobilized onto the above electrodes using EDC-NHS chemistry and further BSA is added to obtain the BSA/anti-CT/APETS@Gd₂O₃/ITO immunoelectrode. Further, this immunoelectrode shows the response for cells in CFU range from 3.125 × 10⁶ to 30 × 10⁶ and is very selective with sensitivity and LOD 5.07 mA CFUs mL cm^-2 and 0.9375 × 10⁶ CFU respectively. To establish a future potential for APTES@Gd₂O₃ NPs in field of biomedical applications and cytosensing, the effect of APTES@Gd₂O₃ NPs on mammalian cells is also observed using in vitro cytotoxicity assay and cell cycle analysis.