Reusable Turn-on Fluorescent Biosensor for Cardiac Biomarker Troponin I Detection Using QDs-SPION-Aptamer.

Tro ponin is a biomolecule found in the blood of humans that can be used as an indicator of cardiac damage and cardiovascular risk. In this study, a turn-on fluorescence-based biosensor was developed using CdSe/ZnS quantum nanoparticles with high fluorescence efficiency decorated on superparamagnetic nanoparticles and aptamer as a probe for cardiac troponin I detection to improve fluorescence efficiency and create a reusable sensor through magnetic separation. Chemical modifications of biosensor components have been characterized by zeta sizer, zeta potential, UV-Vis spectroscopy, transmission electron microscopy (TEM), and Fourier transform infrared spectroscopy (FTIR). We reported that the developed sensor worked with a "Turn-on" mechanism. Fluorescence changes of the developed aptamer-based biosensor were evaluated using a fluorometer, and a low limit of detection (LOD) of 13.3 ng/ml with a linear detection range from 2 to 40 ng/ml was determined. Additionally, the selectivity and sensitivity of the biosensor have been tested with several biomarkers found in human blood.