Electrochemical sensing method for point-of-care cortisol detection in human immunodeficiency virus-infected patients

Ajeet Kaushik,1 Adriana Yndart,1 Rahul Dev Jayant,1 Vidya Sagar,1 Venkata Atluri,1 Shekhar Bhansali,2 Madhavan Nair11Center of Personalized Nanomedicine, Institute of Neuroimmune Pharmacology, Department of Immun­ology, Herbert Wertheim College of Medicine, Florida International University, 2BioMEMS Microsystems Laboratory, Department of Electrical and Computer Engineering, Florida International University, Miami, FL, USA Abstract: A novel electrochemical sensing method was devised for the first time to detect plasma cortisol, a potential psychological stress biomarker, in human immunodeficiency virus (HIV)-positive subjects. A miniaturized potentiostat (reconfigured LMP91000 chip) interfaced with a microfluidic manifold containing a cortisol immunosensor was employed to demonstrate electrochemical cortisol sensing. This fully integrated and optimized electrochemical sensing device exhibited a wide cortisol-detection range from 10 pg/mL to 500 ng/mL, a low detection limit of 10 pg/mL, and sensitivity of 5.8 µA (pg mL)-1, with a regression coefficient of 0.995. This cortisol-selective sensing system was employed to estimate plasma cortisol in ten samples from HIV patients. The electrochemical cortisol-sensing performance was validated using an enzyme-linked immunosorbent assay technique. The results obtained using both methodologies were comparable within 2%–5% variation. The information related to psychological stress of HIV patients can be correlated with disease-progression parameters to optimize diagnosis, therapeutic, and personalized health monitoring.Keywords: psychological stress, personalized health care, cortisol, HIV, electrochemical immunosensing, miniaturized sensing device