Electrochemical determination of 25-hydroxyvitamin D3 using conductive porous template based on gold-modified metal organic framework@mesoporous silica particles

A feasible yet effective electrochemical aptasensor for the detection of 25-hydroxyvitamin D3 (25-OHD3) has been devised based on gold-modified mesoporous silica-zeolitic imidazolate framework-8 (MSS-Z8) composite. The physical as well as electrochemical aspects of Au/MSS/FTO, Au/Z8/FTO, and Au/MSS-Z8/FTO were thoroughly investigated, and Au/MSS-Z8/FTO displayed enhanced electrochemical and electrokinetic performance. Therefore, Au/MSS-Z8/FTO platform has been utilized for electrochemical biosensing of 25-OHD3 by employing 5’ thiolated aptamer specific to 25-OHD3 as biorecognition element. The efficacy of resultant aptasensor was evaluated in [Fe(CN)6]3−/4− redox mediator using differential pulse voltammetry technique. The Apt/Au/MSS-Z8/FTO displayed a highly sensitive (39.1 µA (pg mL−1)−1 cm−2) and selective voltammetric response towards 25-OHD3 within 0.001 to 106 pg mL−1 concentration range with experimental and theoretical detection limit of 0.001 and 0.084 pg mL−1, respectively. Also, the aptasensor performed reliably with both spiked serum samples (Recovery = 97.56–102.1%, RSD = 0.89–2.80%) as well as real serum samples as evident by consistency of results with those obtained from ELISA analysis of real serum samples.