Desenvolvimento de eletrodo modificado com polímero molecularmente impresso (MIP) para o reconhecimento de cortisol

Cortisol is a steroid hormone that realize fundamental role in important physiological processes regulation such as inflammation, blood pressure and glucose levels. Therefore,it is constantly associated with severestress due to the higher production of this hormone in this circumstance indicating that cortisol could be a good biomarker to measure the stress level in biological fluids1. An alternative method to antigen-antibody (A-A) interaction sensor to quantifycortisol is the use of biomimetic materials, such as MIPs, which are more stable and cheap for development of sensorswhen compared with A-Asystems. In this study, a cortisol hydrogel MIP-based and a control Non-Imprinted Polymer (NIP)were synthesized using a similar procedure asreported by Lígia et. al. 2These materials werefirstevaluated by UV-VIS measurements usingcortisol 100 μmol L-1 solution prepared in DMSO containing200 mg of NIP and MIP and mixed on a rotary vortex mixer during 2 min followed by centrifugation. The supernatant was removed and the remainingcortisol concentration was measured.Spectrophotometric resultspointed out that the MIP retains cortisol, and NIP-supernatantdid not show any significant change incortisol concentration. Demonstrated the efficiency to retain the cortisol by the MIP, a glassy carbon surface was modified with the MIP, NIP, MIP-cortisol and NIP-cortisol the modified electrodes were tested using cyclic voltammetry in 1 mmol L-1 potassium ferricyanideas redox probe (Figure 1). Figure 1 showsthat in MIPmodified electrode, thepotassium ferricyanide reaches faster the electrode surface then in NIP, probably due the cavities formed by the template molecules. The voltammograms obtained using NIP-cortisol and MIP-cortisolmodified electrodesshownalmost the same voltammetric behavior obtained for NIP modified electrodedue to the difficult of the redox probe to achieve the electrode surface demonstratting a great potential for selective recognition of cortisolsuing a MIP modified electrode.