We report a new sensitive label-free electrochemical immunosensor to detect Vitamin D₃ (25-OHD₃) in untreated serum samples. To this aim, a graphite screen printed electrode (SPE) was modified using cysteamine (CYM) functionalized core-shell magnetic nanoparticles (Au@MNPs) then, the 25-OHD₃ antibody (AbD) was immobilized via glutaraldehyde crosslinking. The several steps involved in the immunosensor development and 25-OHD₃ analysis were monitored by using differential pulse voltammetry (DPV). The developed immunosensor showed a LOD of 2.4 ng mL⁻¹ and a linear range between 7.4 and 70 ng mL⁻¹. The effectiveness of the immunosensor in human serum analysis was assessed by comparing the results obtained with the chemiluminescence-immunoassay (CLIA) reference method. The high sensitivity and excellent agreement with the reference method suggest its potential use as a POCT to monitor hypovitaminosis 25-OHD levels.

我们报告了一种新的灵敏的无标记电化学免疫传感器，用于检测未经处理的血清样品中的维生素 D ₃ (25-OHD ₃ )。为此，使用半胱胺 (CYM) 功能化核壳磁性纳米粒子 (Au@MNPs) 修饰石墨丝网印刷电极 (SPE)，然后通过戊二醛交联固定 25-OHD ₃抗体 (AbD)。通过使用差分脉冲伏安法 (DPV) 监测免疫传感器开发和 25-OHD ₃分析中涉及的几个步骤。开发的免疫传感器显示出 2.4 ng mL ^-1的 LOD和 7.4 和 70 ng mL ^{-1之间的线性范围}. 通过比较与化学发光免疫测定法 (CLIA) 参考方法获得的结果，评估了免疫传感器在人血清分析中的有效性。高灵敏度和与参考方法的出色一致性表明其可作为 POCT 用于监测维生素缺乏症 25-OHD 水平。