Amperometric mediatorless hydrogen peroxide sensor with horseradish peroxidase encapsulated in peptide nanotubes

By Feyzizarnagh, Hamid; Park, Byung-Wook; Sharma, Lohit; Patania, Michelle M.; Yoon, Do Young; Kim, Dong-Shik
Published in Sensing and Bio-Sensing Research NULL 2016

Abstract

Abstract A mediatorless sensor with horseradish peroxidase (HRP) enzymes encapsulated inside peptide nanotubes (PNTs) has been proposed for amperometric detection of hydrogen peroxide. {PNTs} not only encapsulate the enzymes to retain their activity and stability, but also can provide direct electron transfer between an electrode and the electroactive sites of {HRP} without mediators. Experimental results were compared with hydroquinone (HQ)-mediated electron transfer results. The PNT/HRP sensor produced a current signal comparable to the HQ/HRP sensor in the entire range of hydrogen peroxide concentrations (0-60 mM). The amperometric signal was the greatest when {PNT} and {HQ} were used together. The current signal of the PNT/HQ/HRP system increased rapidly with the hydrogen peroxide concentration while the PNT/HRP and HQ/HRP systems showed a similar increase in the rate of current with hydrogen peroxide. The current-H2O2 concentration relations of the tested systems were analyzed using the Michaelis-Menten type equation. Using {PNTs} as immobilizing agents for enzymes may circumvent the drawbacks of chemical mediators such as {HQ} that may interfere with the redox reactions and may cause toxicity problems to enzymes.

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