Direct electrochemistry and electrocatalysis of hemoglobin on a glassy carbon electrode modified with poly(ethylene glycol diglycidyl ether) and gold nanoparticles on a quaternized cellulose support. A sensor for hydrogen peroxide and nitric oxide

Biosensor for direct bioelectrocatalysis detection of nitric oxide using nitric oxide reductase incorporated in carboxylated single-walled carbon nanotubes/lipidic 3 bilayer nanocomposite

“…This low micromolar Km value also highlights the clear benefits of using an enzyme specific for NO (NOR) on the biosensor. With a couple of exceptions [71,72], most of the NO thirdgeneration biosensors (based on heme proteins and porphyrins [61,69,70]) display considerably higher Km values. Fig.…”

“…Thus, recovery assays were used to assess the selectivity of the PGE/[SWCNTs/(DOPE:DOTAP:DSPE-PEG)/NOR] by testing the presence of compounds that potentially co-exist with NO (or are promoters of NO production) in biological systems. L-arginine (L-Arg), ascorbic acid (AA), sodium nitrate (NO3 − ), sodium nitrite (NO2 − ) and glucose are the most common species that may cause interference during the electrochemical detection of NO [72] and, thus, their individual effect on the NO peak current was tested at 200 μM for L-Arg, NO3 − and NO2 − , 20 μM for AA and 800 μM for glucose, while the NO concentration was 4.76 μM. The biosensor demonstrated excellent performance with recovery values of 98.4 ± 5.3%, 97.3 ± 2.3%, 91.0 ± 9.3%, 91.3 ± 3.0% and 98.0 ± 8.8% for L-Arg, AA, NO3 − , NO2 − and glucose, respectively.…”

Nitric Oxide Detection Using Electrochemical Third‐generation Biosensors – Based on Heme Proteins and Porphyrins

“…In addition, the substrate diffusion should take place easily. The employed approaches for preparation of third‐generation biosensors for NO detection (Table ) are mainly based on adsorption (physical and layer‐by‐layer ), entrapment or covalent bonding . Each method possesses its particular benefits and disadvantages.…”

“…However, leaching of the biocomponent has been reported as a problem due to the weak Van der Waal′s forces and electrostatic or hydrophobic interactions established . Entrapment maintains the bioactivity and has been contributing to reduce heme proteins and porphyrins leakage , but diffusional limitations may happen while high bioelement concentrations are required for electropolymerization . Regarding covalent attachment, its predominant advantages are the reached high stability (leaching of the bioelement is not significant) and the absence of mass transfer limitations, although activity loss may be significant due to conformational changes of even denaturation of the enzyme or protein .…”

“…obtained for Hb the highest K m value of 190 μM demonstrating that the system Hb‐AuPs‐Cys/AuE presents the lowest affinity to NO substrate (Table ). On the other hand, the maximum affinity was assigned to Hb immobilized with gold nanoparticles (AuNPs), cellulose and poly(ethylene glycol diglycidylether) (PEDGE) forming the Hb‐AuNPs‐Cellulose‐PEDGE/GCE biosensor ( K m of 0.0026 μM) , followed by Hb‐CS‐GR‐CTAB/GCE ( K m of 0.315 μM) . It is evident that the use of biopolymers, such as cellulose and chitosan, create adequate and compatible microenvironment benefiting the stabilization and the maintenance of the protein activity.…”