Improved enzyme immobilization for enhanced bioelectrocatalytic activity of choline sensor and acetylcholine sensor

Immobilization of α-amylase on gold nanorods: An ideal system for starch processing

“…However, activation was obtained for immobilized enzyme at early stages of incubation, particularly at 70 • C. Immobilization of ␣-amylse on gold nanorods caused an increase in conformational rigidity of protein structure and limited its freedom to undergo drastic conformational changes. This resulted in an increased stability toward thermal denaturation [4,[34][35][36][37]. A good operating stability is proven with reported results for 1 h incubation period in critical temperature.…”

Amperometric Biosensor Based on Enzymatic Reactor for Choline Determination in Flow Systems

“…The biosensor based on ChOx‐SBA15 reactor exhibited better stability than some of Ch biosensors reported before . In most papers , only the storage stability is reported. However, more important for the evaluation of the enzymatic biosensor performance is to investigate the reusability of one biosensor and to estimate its possible influence the biosensor signal.…”

“…Most of the reported amperometric ChOx‐based biosensors for the determination of Ch are based on monitoring of produced H 2 O 2 in the batch arrangement and have the classic construction with working electrode covered by different types of the supporting layers (poly(diallyldimethylammonium) chloride , a hybrid mesoporous silica membrane , a natural biocompatible polymer chitosan , polyacrylamide microgels , 6‐o‐ethoxytrimethylammoniochitosan chloride , a thiolated silica sol‐gel , polyaniline – silicon dioxide composite , membrane matrix composed of Au nanorods and polyvinyl alcohol , polyvinylferrocenium perchlorate matrix , silica film , poly(pyrrole) and poly(2‐naphthol) films ) at which ChOx is immobilized by various techniques, including electrostatic layer‐by‐layer assembly , glutaraldehyde cross‐linking , adsorption , and sol‐gel deposition . Some of the reported biosensors for the determination of Ch are based on the immobilization of bi‐enzymes acetylcholinesterase‐ChOx or ChOx‐peroxidase . The different electrode materials such as platinum , glassy carbon, pyrolytic graphite, carbon paste , and screen‐printed gold modified with multi‐wall carbon nanotubes , polymer film , nanoparticles (gold , zinc oxide , zirconium oxide , manganese oxide ), FePO 4 nanostructure , and Prussian blue have been used as transducers.…”

Critical overview on the application of sensors and biosensors for clinical analysis

“…Rahman [125] fabricated an electrochemical sensor as a smart chip based on the enzymatic principle, with acetylcholine oxidase being immobilized on the electrode surface via peptide conjugation by amide bond formation. Conversely, Zhang et al [126] developed an electrochemical sensor based on MWCNTs and ZnO nanoparticles for the detection of acetylcholine and choline, which is an enzymatic product of the oxidation of acetylcholine. Monitoring the levels of acetylcholine and choline is crucial for diagnosing neurodegenerative diseases such as Alzheimer's and neuromuscular diseases, myasthenia gravis and impaired cholinergic neurotransmission [127].…”