A novel amperometric biosensor based on a co-crosslinked l-lysine-α-oxidase/overoxidized polypyrrole bilayer for the highly selective determination of l-lysine

Graphene/Poly(vinylferrocene) Composite Based Amperometric Biosensor for L‐lysine Determination

“…Some literature report a similar increase in the activity of the enzyme LyOx in weakly basic media and also emphasize higher electrode responses at higher pH values , . Different pH values such as 5.0 , 6.0 , 7.0 , , , 7.4 , , 7.5 , , 8.0 and 9.0 were also reported for lysine biosensors. However, it is important to highlight that the effect of pH on the biosensor response was not investigated in detail at pH values over 9.0.…”

“…Besides amino acids may be present in different forms (cationic, anionic or the zwitter ion form) based on their isoelectric points (p I ) and the pH. Consequently, when working with amino acids and the related enzymes the pH of the medium becomes relatively critical factor . One has to choose such an optimum pH as the amino acid and related enzyme interact to lead to an enzymatic reaction.…”

“…In this equation m refers to the slope of the calibration graph and S b refers to the standard deviation of 10 different amperometric signals recorded for the lowest L‐lysine concentration (1 μM) in the calibration graph . The detection limit of LyOx/PVF/GR/GCE is lower than that of lysine oxidase/Au nanoparticles/multiwalled carbon nanotubes /polyaniline modified gold electrode (5.0×10 −6 M) , overoxidized polypyrrole film and lysine oxidase modified platinum electrode (4.0×10 −6 M) and glutaraldehyde, bovine serum and lysine oxidase modified platinum electrode (1.0×10 −6 M) . The sensitivity of the LyOx/PVF/GR/GCE was estimated to be as 8.55 μM mM −1 cm −2 with the regression coefficient of 0.998.…”

“…In recent years there has been extensive work towards the development of biosensors because of their characteristics of rapid response, good selectivity, low cost, simple operation, high sensitivity and feasibility of miniaturization , . Various approaches have been made to develop potentiometric , , amperometric and optical , biosensing systems for L‐lysine determination. In L‐lysine biosensors L‐lysine dehydrogenase , L‐lysine‐2‐monooxygenase , L‐lysine‐decarboxylase and L‐lysine‐(α)‐oxidase enzymes have been used as biological recognition element for biosensor fabrication.…”

Amperometric Biosensors for Tyramine Determination Based on Graphene Oxide and Polyvinylferrocene Modified Screen‐printed Electrodes

“…Tyrosine is an electroactive compound and the significant interference from tyrosine may be ascribed to its oxidation at the working potential used in this study . Tryptophan also caused a significant interference (28.3 %) at MAOx/PVF/GRO/SPCE probably due to the oxidation of this electroactive compound .…”