Cortisol Detection using Quantum Dot-Aptamer Probes

Abstract

We present a simple, sensitive approach to detect hormone cortisol using quantum dot (QD)–aptamer probes carried by magnetic nanoparticles. The detection principle is based on the finding that cortisol quenches QDs nearby. Incorporating cortisol-selective aptamers to QDs allows selective capture of free cortisol in analytes. The amount of fluorescence quenching measures the quantity of cortisol binding. The detection signal can be further enhanced by concentration of the probes under magnetic field. The new method does not require additional labeling and achieves a detection limit of