25-Hydroxyvitamin D3 as a main circulating metabolite of vitamin D is usually measured in serum to evaluate the vitamin D status of humans. So, developing an accessible, fast response, sensitive, and selective detection method for 25-hydroxyvitamin D3 is highly important. In this study, we designed a sensitive and selective electrochemical sensor based on the modification of glassy carbon electrode by nanocomposite of CuCo2 O4 /nitrogen-doped carbon nanotubes and phosphorus-doped graphene oxide. Then 25-hydroxyvitamin D3 -imprinted polypyrrole was coated on the electrode surface through electropolymerization. Moreover, ferricyanide was used as a mediator for the creation of a readable signal, which was considerably decreased after rebinding of 25-hydroxyvitamin D3 on the electrode. The proposed sensor successfully detected 25-hydroxyvitamin D3 in the range of 0.002-10 μM, with a detection limit of 0.38 nM, which was highly lower than deficiency concentration (20 ng/ml; 49.92 nM). Finally, the proposed sensor was checked for detection of 25-hydroxyvitamin D3 in serum samples with recovery in the range of 80%-106.42%. The results demonstrated the applicability of the designed sensor for the detection of 25-hydroxyvitamin D3 in biological samples.
Keywords: 25-hydroxyvitamin D3; carbon nanotubes; graphene oxide; imprinted polypyrrole; sensor; transition metal oxide.
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