A Label-Free Electrochemical Aptasensor Based on a Truncated Aptamer for the Detection of Progesterone

This study built an electrochemical label-free progesterone aptasensor to detect progesterone (P4) levels in environmental water samples. The truncated aptamer-modified sulfhydryl adopted self-assembly as a way to stably immobilize at the electrode surface modified by gold nanoparticles (AuNPs). When progesterone combines with the aptamer, the complexes will inhibit electrode surface electron transfer, which reduces the redox peak current value of [Fe(CN)6]3−/4−. As a result, the amount of progesterone combined with the aptamer on the electrode reacted to the electric current’s response values. We have established the relationship between the concentration of progesterone and the current change by a standard curve that is ΔI (μA) = 11.78log CP4 (nM)+48.98. The coefficient of association was 0.9358. The test ranges were from 0.5 nM to 1000 nM. At the same time, other molecules with a similar structure, such as testosterone, estradiol, and 17α-hydroxyl progesterone, had lower response interference than P4. In conclusion, the aptasensor, which had outstanding repeatability and stability, could be applied to determine P4. Food hygiene and clinical diagnosis can be made easier with this newly developed electrochemical biosensor based on aptamers.