Photoelectrochemical Immunosensor Based on ZnIn₂S₄/Bi₂Se₃ Nanocomposite for the Determination of Cardiac Troponin I

Abstract

In this work, a novel flexible photoelectrochemical immunosensor is developed to determine cardiac troponin I (cTnI) in serum. The flower-like ZnIn₂S₄ nanospheres (ZIS), as signal amplification material, were successfully synthesized by a solvothermal method. The ZIS and Bi₂Se₃ were modified on the indium tin oxide- polyethylene terephthalate (ITO-PET) electrode, which effectively accelerates the electronic transition and improved the photocurrent conversion efficiency (signal on). However, the binding of antigen–antibody proteins blocks the electron transfer, resulting in a greatly reduced photocurrent (signal off). By adding the second antibody modified by CdSe quantum dots (CdSe QDs-Ab₂), the photocurrent is increased (signal on). The constructed immunosensor has a linear range from 0.08 to 40 ng/mL with a detection limit of 0.026 ng/mL, which shows excellent selectivity, high sensitivity, and good stability. The photoelectrochemical immunosensor has broad application prospects for the clinical examination of myocardial infarction.

Keywords:

• Cardiac troponin I (cTnI)
• flexible electrode
• flower-like ZnIn₂S₄ nanospheres
• photoelectrochemical immunosensor

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by Guangzhou Construction and Sharing of Technological Innovation Platform (201509090001), Guangzhou, China.