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Improving the sensitivity of electrochemical immunosensor for protein detection
Autoři: Čadková Michaela | Korecká Lucie | Šálek Petr | Metelka Radovan | Bílková Zuzana
Rok: 2012
Druh publikace: ostatní - přednáška nebo poster
Strana od-do: nestránkováno
Tituly:
Jazyk Název Abstrakt Klíčová slova
eng Improving the sensitivity of electrochemical immunosensor for protein detection In area of electrochemical immunosensors, the detection of hydrogen peroxide is of great importance because enzyme horseradish peroxidase is one of the mostly exploited labels in antibodies. Considering the low concentrations of antigens usually determined using labelled antibodies, it is necessary to enhance the final detection signal as much as possible. Moreover, there is a continuous push to miniaturize whole analytical system and measurements in lowest possible sample volume.Since direct sorption of antibodies onto electrode surface causes poor regeneration of sensors and affects reproducibility of experiments, we use magnetic particles with oriented and covalently bonded antibodies. It allows the repeated use of screen-printed three electrode sensors, comprised of the reference Ag/AgCl electrode and platinum auxiliary and working electrodes (BST, Germany; DropSens, Spain). After testing different configurations, measurements were found feasible down to 50 µl volume. To ascertain the optimal experimental conditions for sensitive hydrogen peroxide detection in proposed protein electroimmunoassay, the enzyme HRP was immobilized firstly onto the surface of magnetic microspheres HPM-07-SM64 with –SO3- functional groups newly developed at the Institute of Macromolecular Chemistry Academy of Science Prague. The current decrease of hydrogen peroxide oxidation signal was electrochemically monitored by the LSV technique using screen-printed sensors and PalmSens compact electrochemical sensor interface (Palm Instruments BV, Netherlands). To enhance the electrochemical response, usually an electron mediator is introduced. For our purposes, the thionine has been used. Its effect on hydrogen peroxide detection under various experimental conditions in 0.1 M phosphate buffer pH 7.3 with addition of 0.15 M NaCl was thoroughly tested. It was evident that the addition of thionine positively influenced the measured signal and made the proposed electroimmunoassay more sensitive. biosensor; electrochemical detection; ovalbumin; anti-ovalbumin; hydrogen peroxide