Portable graphene oxide modified immunosensor for the detection of Vitamin D3

The prompt asserts that identifying low levels of vitamin D (hypovitaminosis D) in pregnant women and infants at an early stage is crucial due to the irreversible clinical consequences that can result. The measurement of 25hydroxy Vitamin D3 levels can serve as a valuable indicator of the risk of developing Vitamin D deficiency. Graphene, a two-dimensional material composed of sp2 hybridized carbon atoms, is highly regarded due to its exceptional thermal, electronic, optical and mechanical properties, as well as its single-atom thickness and large surface area. In this investigation, graphene oxide (GO) were incorporated into paper electrodes, creating a costeffective material that served as a matrix for developing an immunosensor. Using modified Hummer's method, graphene oxide was synthesized and subsequently drop-cast onto the surface of a screen-printed paper electrode (SPPE), resulting in enhanced electrochemical signal. Thereafter, SPPE was modified with graphene oxide (GO) and further functionalized with 25-hydroxy Vitamin D3 monoclonal antibody using cross-linking chemistry of EDC:NHS. To characterize the synthesized GO, various analytical techniques were employed, including UV-Vis, FT-IR, Particle Size Analyser, Raman analysis, FE-SEM, TEM and XRD analyses. The stratified modification of the electrode surface was monitored through FT-IR and EIS techniques. Finally, the sensor response was measured after hybridization with different antigen concentrations by CV and DPV analyses. For electrochemical measurements, "K3[Fe (CN)6]3-/4- (5 mM in PBS buffer, pH 7.2)" was utilized as a redox indicator. The developed smart phone android based immunosensor showed a sensitivity of 2036.12 mu A/mm2/fg and LOD 5.96 fg/mu L for electrochemical detection of vitamin D3.