Real-Time Sensing of Hydrogen Peroxide by ITO/MWCNT/Horseradish Peroxidase Enzyme Electrode

Abstract

The accurate and sensitive determination of H2O2 is very important in many cases because it is a product of reactions catalysed by several oxidase enzymes in living cells and it is essential in environmental and pharmaceutical analyses. The fabrication of enzyme protein activity based biosensors is a very promising way for this purpose because the function of biological molecules is very specific, sensitive, and selective. Horseradish peroxidase (HRP) is the most commonly used enzyme for H2O2 detection because it can oxidize hydrogen atoms and, for example, xenobiotics in the presence of H2O2. In order to define the limit of detection (LOD) of H2O2 we made calibrations with guaiacol and amplex red (AR), which are hydrogen donors of HRP. The accumulation of the reaction products, tetraguaiacol, and resorufin, respectively, then can be easily detected by absorption or emission (fluorescence) spectroscopy. In our experiments an enzyme electrode was fabricated from ITO (indium tin oxide), functionalized multiwalled carbon nanotubes (f-MWCNTs), and HRP. Although the enzyme activity was smaller by about two orders of magnitude when the enzyme was bound to the f-MWCNTs (ca. 10−2 M H2O2/(M HRP·sec) compared to ca. 2 M H2O2/(M HRP·sec) and 5 M H2O2/(M HRP·sec) with AR and guaiacol in buffer solution), LOD of the H2O2 decomposition was about 6 pM H2O2/sec and 10 pM H2O2/sec in the case of AR and guaiacol, respectively.

Advancements in 2D Materials Based Biosensors for Oxidative Stress Biomarkers

“…Magyar et al used indium tin oxide (ITO) functionalized with multiwalled carbon nanotubes (MWCNTs) and horseradish peroxidase (HRP) for the real time measurements of hydrogen peroxide. 136 In yet another study, HRP-AP/ rGO (AP: 1-aminopyrene as a linker between HRP and rGO) modified glassy carbon electrode was used for intracellular hydrogen peroxide detection. 137 Though bioreceptor based (bio)sensors are famous for their inherent specific activity, they suffer from disadvantages like high cost of bioreceptors, loss in their activity with time, and other physiological parameters.…”

“…Hydrogen peroxide, another important oxidative stress marker, has also been detected using electrochemical techniques where 2D materials have been used either as immobilization surface or as catalysts. Magyar et al used indium tin oxide (ITO) functionalized with multiwalled carbon nanotubes (MWCNTs) and horseradish peroxidase (HRP) for the real time measurements of hydrogen peroxide . In yet another study, HRP-AP/rGO (AP: 1-aminopyrene as a linker between HRP and rGO) modified glassy carbon electrode was used for intracellular hydrogen peroxide detection .…”

Photosynthetic reaction center/graphene bio-hybrid for low-power optoelectronics

“…The new generation of technologies offers unique solutions for specific tasks, such as optimizing the size of the devices and sample quantity, aiming single-molecular, fast, reversible, online, real-time, remote operation, and highly reproducible, sensitive, selective responses (Magyar et al 2013(Magyar et al , 2016Luka et al 2015. There is a large number of reports and reviews summarizing the advantageous properties of graphene for a wide range of applications referring to its unique transport properties (optical and electric conductivity) (Geim andNovoselov 2007, Geim 2009) as well as its extraordinarily high mechanical (strength and flexibility) and chemical stability (Blake et al 2008, Wang et al 2008, Kim et al 2009, Li et al 2009.…”

Functional Nanohybrid Materials from Photosynthetic Reaction Center Proteins

“…One should optimize the size of the devices and sample quantities-aiming for single molecular operation and/or fast, reversible, and reproducible responses, also for online, real-time, sensitive, and selective detection [13][14][15]. Discovering new types of materials and technologies led to the birth of new phenomena and disciplines, like optoelectronics, (bio)photonics, nanotechnology, and nanobionics.…”