Biomimetic sensing of progesterone in pharmaceutical samples

ANABEL LAZA CORREA; GODOY, ANA; PEREIRA, SIRLEY V; ARANDA P; MESSINA GERMÁN A.; CARLOS D. GARCIA; BERTOLINO F; J. RABA

WASHINGTON, DC

Congreso; TechConnect; 2022

Progesterone (P4) is a steroid hormone with an important role in the reproduction process of humans and other species. When P4 is bound to its specific receptors, is able to induce pregestational effects as well as affect the activity of other steroids and drugs [1]. Quantification of P4 is essential to ensure adequate quality control during production, to identify counterfeit products [2], to monitor veterinary use [3] and to maintain patients within their therapeutic ranges, issue that is especially critical for in-vitro fertilization [4]. Traditional determination of P4 has been performed by HPLC [5], GC, or immunoassays [6]. Electrochemical biosensors represent an interesting choice due to this kind of devices can provide miniaturization, portability, and accurate progesterone determinations [7]. Despite the outstanding progress in this field, the utility of many of these biosensors is often limited by the complexity of the detection electrode [8], its cost and/or the stability of the selected biorecognition element [9]. Aiming to address these limitations, a number of molecularly imprinted polymers (MIP) have been used for the development of P4 sensors with relevant analytical performance [10]. MIPs are synthetic polymeric materials with molecular recognition sites that are able confer a selectivity that is similar or equal to that provided by antibodies, enzymes, DNA, or aptamers [11]. The proposed approach represents one of the simplest and fastest routes to develop the sensors.Taking into account the mentioned advantages, a biomimetic sensor for the determination of progesterone (P4) was successfully developed, using a molecularly imprinted polymer as recognizing element. As a first stage, of the design process, gold nanoparticles were electrogenerated on the glassy carbon electrode surface by reduction of HAuCl4 solution 0.6 mmol L-1 at constant potential of -200 mV applied for 60 seconds. These nanoparticles incorporation improve the electrochemical response of the sensor and also serve as a basis for the electropolymerization by cyclic voltammetry. As a second stage, AuNPs/GCE was immersed in a solution containing penicillamine 0.05 mol L-1 in ethanol, to coat the surface via thiol-linkages. Finally, in order to obtain a polymeric film on the surface of glassy carbon electrode modified with AuNPs, aminophenol (pAP) in the presence of P4 was subjected to 15 cycles between -0.1 and 1.2 V, with a scan rate of 100 mV.s-1 (Figure 1).Figure 1: Summary of the process implemented for the preparation of the MIP/Au/GCE, including the formation of AuNPs, their modification with penicillamine, and the electropolymerization of the pAP in the presence of the template molecule (P4).The developed biomimetic sensor for the determination of P4 was developed in a very simple process with great selectivity. This sensor presents competitive characteristics with biosensors and great chemical stability, being possible to use it several times while maintaining good response. It. presented good analytical characteristics for the determination of P4 with a linear response range from 0.75 to 45 μM with detection and determination limits of 0.12 μM and 0.41 μM, respectively. The sensor´s selectivity was studied with compounds with very similar structure to P4 and no interference effects were observed. Regarding to the stability the sensor could be used even 30 days after its preparation and it is reusable at least 12 times maintaining a good response. The design and construction of the sensor is very simple and fast, achieving an electrochemical sensor with great selectivity, reproducibility (RSD=2.3%) and stability. The sensor was successfully used in the determination of P4 in pharmaceutical formulations.