One pot synthesized zirconia nanoparticles embedded in amino functionalized amorphous carbon for electrochemical immunosensor

Zirconia nanoparticles embedded in amino functionalized amorphous carbon (nZrO2-NH2C) nanocomposite were synthesized by a novel, simple and one-pot hydrothermal method. The hydrothermal synthesis process involved carbonization of chitosan into amino functionalized amorphous carbon (NH2C) and simultaneously in-situ growth of zirconia nanoparticles (nZrO2). The existence of carbon into the nanocomposite during the synthesis enhanced mechanical strength of nZrO2. Beside this, the presence of NH2C in nanocomposite minimized the aggregation of nZrO2 (~ 10 nm), and hybrid interface of nZrO2-NH2C that enhanced the electrochemical properties. The NH2C also improved the wettability of the nanocomposite as observed by contact angle measurement. This nZrO2-NH2C nanocomposite was deposited onto indium tin oxide (ITO) coated glass substrate using the electrophoretic technique. The oxygen moieties of nZrO2 and amine groups of NH2C in nanocomposite formed an admirable microenvironment for immobilization of anti-OTA (antibodies specific to Ochratoxin A). XPS and FTIR studies revealed the presence of amine groups on nZrO2-NH2C nanocomposite and immobilization of biomolecules (anti-OTA and BSA) on its surface, respectively. The fabricated BSA/anti-OTA/nZrO2-NH2C/ITO immunosensor revealed a selective detection of OTA in the detection range from 1 to 10 ng mL− 1 with a sensitivity of 0.86 μA ng− 1 mL cm2 and lower detection limit of 1 ng mL− 1.