An efficient electrochemical biosensor for Vitamin-D3 detection based on aspartic acid functionalized gadolinium oxide nanorods

Abstract

In this study, an efficient electrochemical biosensor for Vitamin-D3 detection using gadolinium oxide nanorods (Gd2O3NRs) has been reported. Gd2O3NRs were hydrothermally synthesized and functionalized with aspartic acid (Asp-Gd2O3NRs). Asp functionalization did not change the phase, shape and structure of Gd2O3NRs. The high-resolution transmission electron microscopy study revealed the diameter of Asp-Gd2O3NRs as 14.26 ± 0.13 nm with enhanced dispersivity. The Gd2O3NRs and Asp-Gd2O3NRs showed zeta potential of +29 and +24 mV, respectively. Asp-Gd2O3NRs exhibited enhanced hydrophilicity and electrochemical property than the bare Gd2O3NRs. A thin film of Asp-Gd2O3NRs was deposited on a glass substrate coated with indium-tin-oxide (ITO) by electrophoretic deposition. The immobilization of Vitamin-D3 monoclonal antibody (Ab-VD) was done on the surface of Asp-Gd2O3NRs/ITO electrode for determination of Vitamin-D3. The study of BSA/Ab-VD/Asp-Gd2O3NRs/ITO immunoelectrode response with different Vitamin-D3 concentration was investigated using differential pulse voltammetry technique. The results of response study exhibited an improved sensitivity value of 0.38 μA ng−1 mL cm−2 with a linear range of 10–100 ng mL−1 for Vitamin-D3 detection while the detection limit of 0.10 ng mL−1 was obtained. This immunosensor showed a satisfactory response to commercially available Vitamin-D3 oral solution. Besides this, in vitro study of Gd2O3NRs and Asp-Gd2O3NRs was performed on RAW 264.7 and MCF-7 cells. Keywords: Gadolinium oxide, Nanorods, Aspartic acid, Vitamin-D3, Electrochemical immunosensor