Exploration of an Electrochemical Sensor for Continuous Monitoring of Estradiol in Application to Fertility Tracking

Space Dynamics Laboratory, Auditorium Rm B

Estradiol is one of three estrogens, the primary female sex hormone; it fluctuates diurnally, and monthly, dictating the menstrual cycle. We developed a bench-top electrochemical sensor to detect estradiol with the intention of future realization into an implantable, continuously sampling sensor to be used as an aid for fertility health. The electrochemical sensor is comprised of a three electrode system which utilizes a gold working electrode, platinum counter electrode, and Ag/AgCl reference electrode to perform cyclic voltammetry. A monolayer of estradiol aptamers and mercaptohexanethiol coat the working electrode surface. The monolayer was exposed to 10ng/mL, 100n/mL and 1,000ng/mL of estradiol. The capacitive change was detected through cyclic voltammetry. We determined that the estradiol concentration was the most significant factor in influencing the resulting capacitance. The experiments to determine when estradiol molecules were dissociating from the aptamers were inconclusive; however, theory leads us to believe that the aptamers will dissociate with minimal lag, depending on the equilibrium dissociation constant. Currently, the sensor can work for a bench-top detection of estradiol, but the sensitivity and size must be optimized for an implantable.