A Nitric Oxide Biosensor Based on Horseradish Peroxidase/Kieselguhr Co‐Modified Pyrolytic Graphite Electrode

Abstract

A reagentless nitric oxide (NO) biosensor was prepared using a pyrolytic graphite (PG) electrode modified with a composite film containing horseradish peroxidase (HRP) and kieselguhr. Noticeably, the electron-transfer reactivity of HRP was significantly enhanced when incorporated in the inorganic kieselguhr material. Consequently, we observed the direct electrochemical response of HRP in this composite film, which would be otherwise electrochemically silent (in the absence of kieselguhr). Importantly, this modified electrode demonstrated nice catalytic activity, as well as high stability, towards the reduction of NO. The peak current related to NO was linearly proportional to its concentration from 2.0 x 10(-7) to 2.0 x 10(-5) mol/L, and the relative standard deviation was 4 % for five successive determinations at a NO concentration of 1.0 x 10(-5) mol/L. The critical level in concentration was estimated to be (4.0 +/- 0.3) x 10(-8) mol/L.

Review of recent advances in analytical techniques for the determination of neurotransmitters

“…Inorganic surface modifications included single walled carbon nanotubes and Nafion,[281] and gold nanoparticles. [282] Protein or enzyme modifications were horseradish peroxidase and kieselguhr,[288] hemoglobin,[284] hemoglobin and myoglobin,[285, 287, 289] cytochrome c,[283] and red blood cells immobilized on gold nanoparticles. [286] Studies of NO in biological models are often performed on cultured single cells to eliminate the complication of distinguishing NO from several cellular sources.…”

“…DAFs often experience interference from dehydroascorbice acid and ascorbic acid. Sweedler and collegues demonstrated this interference could be avoided through the introduction of ascorbic acid oxidase,[288] by use of dual labeling with two fluorophores with different excitation wavelengths,[293] and by diffusive mixing of NO and the fluorophore in frozen blocks of sample and fluorophore, excluding interfering species which cannot diffuse through the solid phase to the fluorophore. [292] Yang et al .…”

Nanomaterials-based electrochemical sensors for nitric oxide

“…The sensitive sensing system is also well-designed to further improve the analytical performance of NO sensor. There are two major channels for the design of NO sensitive surface, one is to employ redox mediator, such as macrocyclic metal complexes [31][32][33][34][35][36][37][38], watersoluble dyes [39][40][41][42][43] or metalloproteins [44][45][46][47][48][49], and the other is to introduce nanomaterials for the construction of the sensing interface.…”

Electron transfer and interfacial behavior of redox proteins

“…Hb, incorporated in a kieselgubr film, may even exhibit a comparatively higher heterogeneous ET rate than that in montmorillonite film [31]. Therefore, kieselgubr film has been used to entrap such proteins as horseradish peroxidase (HRP) to obtain DET and to develop more biosensors [32,33].…”