Carbon cloth-based immunosensor for detection of 25-hydroxy vitamin D 3 .

Vitamin D (VD) deficiency is a global health concern due to its serious health impacts, and at present, the monitoring of VD status is expensive. Here, a novel immunosensor for sensitive and label-free detection of 25-hydroxy vitamin D ₃ (25VD ₃ ) is reported. Nanostructured cerium(IV) oxide (nCeO ₂ ) was anchored onto carbon cloth (CC) via electrophoretic deposition to fabricate a nanoplatform (nCeO ₂ /CC). Subsequently, bioactive molecules (anti-25VD ₃ and BSA) were introduced to fabricate the nanobioplatform BSA/anti-25VD ₃ /nCeO ₂ /CC as an immunosensor. The analytical performance of the developed immunosensor was studied towards 25VD ₃ detection. The immunosensor provides a broad linear range of 1-200 ng mL ^-1 , high sensitivity of 2.08 μA ng ^-1  mL cm ^-2 , a detection limit of 4.63 ng mL ^-1 , and a response time of 15 min, which is better than that of previous reports. The biosensor exhibited high selectivity, good reproducibility, and excellent stability for about 45 days. The potential application of the proposed immunosensor was observed for real serum samples towards 25VD ₃ detection that demonstrated a high correlation with the conventional enzyme-linked immunosorbent assay. Graphical abstract.