Environmental and medical applications of molecularly imprinting polymer sensor for the detection of progesterone
Abstract
Molecularly imprinted polymers are spatial technique with artificial recognition sites compatible to the template size, shape, and functional groups arrangement. The MIPs have shown high selectivity and affinity for the target molecules with a substantial potential for the hormones detection as an environmental sensor. The objective of this research is to fabricate a label-free molecular imprinted polymer (MIPs) sensor and investigate the sensing ability for progesterone detection in aqueous solutions and blood. The Progesterone (PGN) is a cholesterol-long biosynthetic endocrine disruptor steroid and is naturally occurring estrogenic compound with a majority effect to alter the vital functions of the human body. The MIPs detection was based on the reflectance mechanism of inverse opal film, after the PG attachment into the photonic MIP binding sites modified the Bragg diffraction spectra of the films due to swelling and refractive index changes, producing the optical signal. MIPs were investigated by equilibrium binding, kinetics experiments, and UV- visible spectra that occurs with the rebinding at different progesterone concentrations in deionized water and 150 mM NaCl solutions. The MIPs response were investigated with progesterone concentration in the 1-100 [mu]g L-1 range; with LOD of 0.5 [mu]g L-1, reaching the detected range of hormone in natural waters. Furthermore, hydrogel MIP films were successfully tested in various real water matrices, they revealed satisfactory recognition ability towards the analyte, and a promising performance in challenging, unknown natural water samples. Moreover, the MIPs film exhibited good selectivity towards the progesterone hormone when exposed to structurally similar molecules, evidenced by a larger response than non-imprinted films (NIPs) due to the specific adsorption provided by molecular imprinting. Computational studies suggested that size along with surface potential influenced the binding of analog compounds. The molecularly imprinted polymer (MIP) were applied to whole blood and plasma samples of three different animals, the levels of free and total PG were analyzed along with different days of the estrous cycle of the cows. The commercial PG kits test results followed the same trend with MIPs test results for the non-bound PG in the blood samples. The measurements revealed the minimum concentration at day 0, and highest level between day 10 and 14. Both MIPs and commercial PG kits test results were in agreement in evaluating the PG levels trend during the estrous cycle, however, there was some variance in evaluating the exact concentrations of PG hormone during the cycle, but no discrepancy in determining the cow's pregnancy profile.
Degree
Ph. D.