LAUSR

Abstract This work demonstrates a label-free photoelectrochemical (PEC) aptamer sensor based on poly(5-formylindole)/Au (P5FIn/Au) nanocomposites for the ultrasensitive determination of thrombin (TB). As a photosensitive material, P5FIn exhibits excellent photocurrent response under visible light irradiation, and can capture more thrombin aptamers (TBA) due to large specific surface area and surface-rich aldehyde group. In addition, the aldehyde groups of P5FIn are conducive to the stable and efficient immobilization of aptamers or bioactive molecules, enhancing their biological activity. Au increases the absorption of visible light and effectively inhibits the recombination of photogenerated electron-hole pairs, thereby improving the photocurrent conversion efficiency of P5FIn. Therefore, after TB is specifically identified, the photocurrent decreases linearly. Under optimal conditions, this PEC aptasensor has a linear response ranging from 0.001 to 10 nM with detection limits as low as 0.2 pM. This sensor also has good selectivity, repeatability, stability and simple construction process. The determination results of TB in real human serum samples are also satisfactory, which will provide a practical PEC platform for the rapid detection of proteins in the future.