Selective electrochemical sensing of human serum albumin by semi-covalent molecular imprinting

Abstract

We devised and prepared a conducting molecularly imprinted polymer (MIP) for human serum albumin (HSA) determination using semi-covalent imprinting. The bis(2,2'-bithien-5-yl)methane units constituted the MIP backbone. This MIP was deposited as a thin film on an Au electrode by oxidative potentiodynamic electropolymerization to fabricate an electrochemical chemosensor. The HSA template imprinting, and then its releasing from the MIP was confirmed by the differential pulse voltammetry (DPV), electrochemical impedance spectroscopy (EIS), XPS, and PM-IRRAS measurements as well as by AFM imaging. Semi-covalent imprinting provided a very well defined locations of recognition sites in the MIP molecular cavities. These sites populated the imprinted cavities or the MIP surface only. The DPV and EIS response of the MIP film coated electrode to the HSA analyte was linear in the range of 0.8 to 20 and 4 to 80 µg/mL HSA, respectively, with the limit of detection of 16.6 and 800 ng/mL, respectively. The impressively high imprinting factor reached, exceeding 20, strongly confirmed that semi-covalent imprinting resulted in formation of a large number of very well defined molecular cavities with high affinity to the HSA molecules. The MIP selectivity against low-(molecular weight) interferences, common for physiological fluids, such as blood and urea, was very high. There was no response to the presence of these interferences at concentrations encountered in the samples analyzed. Moreover, the chemosensor selectivity to the myoglobin and cytochrome c interferences was excellent while that to lysozyme was slightly lower but still high. The chemosensor was useful for determination of abnormal HSA concentration in a control blood serum.

Electrosynthesized molecularly imprinted polyscopoletin nanofilms for human serum albumin detection

“…MIPs [22] as reported earlier and overall suggests as a perspective application for genuine 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 …”

“…substrates or inhibitors of an enzyme target [18,19], aptamers [20] and various nanomaterials [16,21]. Alternatively, rational design of monomers tuned for the specific target and semi-covalent imprinting was also shown to give MIPs with high affinity towards protein templates [22].…”

Self-Reporting Molecularly Imprinted Polymer for Label-Free Selective Electrochemical Sensing of p-synephrine

“…However, this mechanism seems to be inadequate for electrochemical sensors with conductive MIP film recognition units. For example, electrochemical impedance spectroscopy spectra recorded in our previous research [5,6] clearly indicate that redox probe diffusion to the electrode surface was not affected by analite binding into MIP film. Moreover, well pronounced changes in charge transfer resistance were observed.…”

Sensor Array Based on Molecularly Imprinted Polymers for Simultaneous Detection of Lipoproteins

“…Coupled with suitable transducers they lead to appreciable biological assays. To date protein imprinting approaches demonstrate broad applicability in the area of biomedical analysis, including detecting human serum albumin (HSA) [2], human papillomavirus derived E7 protein [3], and insulin [4].…”