Abstract
Abstract An amperometric hydrogen peroxide biosensor using a nanobiocomposite based on neutral red modified carbon nanotubes and co-immobilized glucose oxidase and horseradish peroxidase is reported. Modification of the nanobiocomposite electrode with neutral red resulted in a sensitive, low-cost and reliable H2O2 sensor. The use of carbon nanotubes, as the conductive part of the composite, facilitated fast electron transfer rates. The biosensor was characterized for the influence of pH, potential and temperature. A remarkable feature of the biosensor is the detection of H2O2 at low applied potentials where the noise level and interferences are minimal. The sensor has a fast steady-state measuring time of 10 s with a quick response (2 s). The biosensor showed a linear range from 15 nM to 45 mM of H2O2 and a detection limit of 5 nM. Nafion, which is used as a binder, makes the determination free from other electroactive substances. The repeatability, reproducibility, stability and analytical performance of the sensor are very good.
Highlights
Nanotechnology offers the potential to increase biosensor sensitivity, response speed and selectivity
Their unique properties [4] have led their applications in many fields such as electronics, medicine, aerospace industry, etc., which has prompted the need of analytical methodologies to characterize and control the quality of these nanomaterials
The SEM image of the multiwalled carbon nanotubes (MWNTs)/neutral red (NR)/GOx/HRP/Nf nanobiocomposite is given in Fig. 1(a) and the enzyme immobilized NR/MWNTs were confirmed with Fourier transform infrared spectroscopy (FTIR) spectra (Fig. 1(b))
Summary
Nanotechnology offers the potential to increase biosensor sensitivity, response speed and selectivity. Incorporation of carbon nanotubes (CNT) and fullerenes has greatly increased biosensor sensitivity and response speed due to their high chemical stability, high surface area, and unique electronic properties [3]. The irruption of carbon nanotubes has constituted a significant milestone in modern analytical sciences Their unique properties [4] have led their applications in many fields such as electronics, medicine, aerospace industry, etc., which has prompted the need of analytical methodologies to characterize and control the quality of these nanomaterials. Electrode modification with CNTs gives electrocatalytic activity towards the electro-oxidation of molecules such as NADH or H2O2 [5] This property led to the use of these nanomaterials for the preparation of dehydrogenase or oxidase based electrochemical biosensors [6,7,8,9,10]. An increased electrode active surface area, which gives rise to enhanced electrochemical response, and a demonstrated
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