Mesoporous platinum nanozyme-based competitive immunoassay for sensitive detection of 25-hydroxyvitamin D

[Display omitted] •Mesoporous platinum nanozymes (MPNs) were fabricated by a surfactant-based self-assembly method.•MPNs showed the higher peroxidase-mimic activity than horseradish peroxidase.•MPNs were applied to colorimetric vitamin D detection using a competitive immunoassay.•MPNs-based immunoassay exhibited good linearity for vitamin D detection with a LOD of 1.0 ng/mL. In this study, mesoporous platinum nanozymes (MPNs) were fabricated by a surfactant-based self-assembly method and then used to develop a novel competitive immunoassay for sensitive detection of 25-hydroxyvitamin D3 (25(OH)VD3). The MPNs showed enhanced peroxidase-like activity that catalyzes the reaction between hydrogen peroxide (H2O2) and 3,3′,5,5′-tetramethylbenzidine (TMB). The excellent peroxidase-like MPNs were employed to develop a competitive immunoassay for the sensitive colorimetric detection of 25(OH)VD3. The immunoassay detected 25(OH)VD3 in the range of 1.6 to 100 ng/mL, with a detection limit of 1.0 ng/mL. The recovery values of 25(OH)VD3 from the spiked human serum samples were between 104% and 95%. These results indicate the applicability of MPNs as alternatives for natural enzymes and the feasibility for sensitive 25(OH)VD3 detection.