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

In this study, an efficient electrochemical biosensor for Vitamin-D3 detection using gadolinium oxide nanorods (Gd(2)O(3)NRs) has been reported. Gd(2)O(3)NRs were hydrothermally synthesized and functionalized with aspartic acid (Asp-Gd(2)O(3)NRs). Asp functionalization did not change the phase, shape and structure of Gd(2)O(3)NRs. The high-resolution transmission electron microscopy study revealed the diameter of Asp-Gd(2)O(3)NRs as 14.26 +/- 0.13 nm with enhanced dispersivity. The Gd(2)O(3)NRs and Asp-Gd(2)O(3)NRs showed zeta potential of +29 and +24 mV, respectively. Asp-Gd(2)O(3)NRs exhibited enhanced hydrophilicity and electrochemical property than the bare Gd2O3NRs. A thin film of Asp-Gd(2)O(3)NRs 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-Gd(2)O(3)NRs/ITO electrode for determination of Vitamin-D3. The study of BSA/Ab-VD/Asp-Gd203NRs/ITO immunoelectro de response with different Vitamin-D-3 concentration was investigated using differential pulse voltammetry technique. The results of response study exhibited an improved sensitivity value of 0.38 mu A mg(-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-D-3 oral solution. Besides this, in vitro study of Gd(2)O(3)NRs and Asp-Gd(2)O(3)NRs was performed on RAW 264.7 and MCF-7 cells. (C) 2019 The Authors. Published by Elsevier B.V.