The development of an electropolymerized, molecularly imprinted polymer (MIP) sensor for insulin determination using single-drop analysis

An electrochemical sensor for the detection of insulin in a single drop (50 mu L) was developed based on the concept of molecularly imprinted polymers (MIP). The synthetic MIP receptors were assembled on a screen-printed carbon electrode (SPCE) by the electropolymerization of pyrrole (Py) in the presence of insulin (the protein template) using cyclic voltammetry. After electropolymerization, insulin was removed from the formed polypyrrole (Ppy) matrix to create imprinting cavities for the subsequent analysis of the insulin analyte in test samples. The surface characterization, before and after each electrosynthesis step of the MIP sensors, was performed using atomic force microscopy, scanning electron microscopy, and energy-dispersive X-ray spectroscopy. The performance of the developed MIP-SPCE sensor was evaluated using a single drop of solution containing K3Fe(CN)(6) and the square-wave voltammetry technique. The MIP-SPCE showed a linear concentration range of 20.0-70.0 pM (R-2 = 0.9991), a limit of detection of 1.9 pM, and a limit of quantification of 6.2 pM. The rapid response time to the protein target and the portability of the developed sensor, which is considered a disposable MIP-based system, make this MIP-SPCE sensor a promising candidate for point-of-care applications. In addition, the MIP-SPCE sensor was successfully used to detect insulin in a pharmaceutical sample. The sensor was deemed to be accurate (the average recovery was 108.46%) and precise (the relative standard deviation was 7.23%).

Automated summary

An electrochemical sensor based on molecularly imprinted polymers (MIP) was developed for the detection of insulin in a single drop. The MIP receptors were assembled on a screen-printed carbon electrode (SPCE) through electropolymerization, creating imprinting cavities for insulin detection. The sensor showed a linear concentration range, a low detection limit, and good accuracy and precision.