▎ 摘　　要

NOVELTY - Developing label free immunosensor to detect vitamin deficiency, comprises preparing graphene nanoribbons (GNRs) that is used in the electrode matrix, (b) labeling antibodies for 25-hydroxyvitamin D (Ab-25(OH)D3) with ferrocene carbaldehyde (Fc-CHO), (c) obtaining label free immunosensing platform by drop-casting 4 mu l of prepared GNRs into a screen printed electrode (SPE), (d) incubating the electrode surface with7 mu l Ag-25(OH)D3 solution at series of various concentrations at certain temperature for definite amount of time to remove uncombined Ag-25(OH)D3 with Ab-25(OH)D3, (e) inspecting immobilized steps by SEM analysis, and the scanning electron microscope (SEM) images that clearly depicts the changes in the morphology of the electrode surface and also confirms the successful loading of biomolecules onto GNRs electrode surface. USE - The method is useful in selective detection of 25(OH)D3 in biological samples. ADVANTAGE - The method is stable, has good bio-specificity, effectively detects 25(OH)D3 in human serum samples, has rapid detection time, unique sensitivity, cost-viability, and outstanding compatibility with miniaturization technologies. DETAILED DESCRIPTION - Developing label free immunosensor to detect vitamin deficiency, comprises (a) preparing graphene nanoribbons (GNRs) that is used in the electrode matrix, (b) labeling antibodies for 25-hydroxyvitamin D (Ab-25(OH)D3) with ferrocene carbaldehyde (Fc-CHO), where the number of ferrocenes into Ab-25(OH)D3 is studied using the inductively coupled plasma-optical emission spectrometry technique (ICP-OES) which detects the iron concentration in modified Ab-25(OH)D3, (c) obtaining label free immunosensing platform by drop-casting 4 mu l of prepared GNRs into a screen printed electrode (SPE), (d) incubating the electrode surface with7 mu l Ag-25(OH)D3 solution at series of various concentrations at certain temperature for definite amount of time to remove uncombined Ag-25(OH)D3 with Ab-25(OH)D3, (e) inspecting immobilized steps by SEM analysis, where the electrode surface is changed after binding of Ab-25(OH)D3-Fc which indicates the coverage of the electrode surface and immobilization of bovine serum albumin (BSA) further changes the electrode surface into smooth morphology, and the scanning electron microscope (SEM) images that clearly depicts the changes in the morphology of the electrode surface and also confirms the successful loading of biomolecules onto GNRs electrode surface.