A Simple Cortisol Biosensor Based on AuNPs-DNA Aptamer Conjugate

Cortisol plays a key role in maintaining human life, regulating body material metabolism, promoting the development of secondary sexual characteristics and ensuring human normal biological function. We have studied an AuNPs-DNA conjugate aptamer biosensor. 20 nm AuNPs were prepared by seed method, and cortisol aptamer were bonded to the surface of gold nanoparticles by Au-S bond. When DNA aptamer binds to cortisol, the intensity of UV-Vis absorption peak of AuNPs decreases. The biosensor can quantitatively detect cortisol at the nanomolar level. The detection range of the biosensor is 1-1000 nM. In addition, the biosensor does not recognize cortisol related compounds, indicating its high selectivity.