title: Nanostructured biosensor for measuring neuropathy target esterase activity.
abstract: Neuropathy target esterase (NTE) is a membrane protein found in human neurons and other cells, including lymphocytes. Binding of certain organophosphorus (OP) compounds to NTE is believed to cause OP-induced delayed neuropathy (OPIDN), a type of paralysis for which there is no effective treatment. Mutations in NTE have also been linked with serious neurological diseases, such as motor neuron disease. This paper describes development of the first nanostructured biosensor interface containing a catalytically active fragment of NTE known as NEST. The biosensor was fabricated using the layer-by-layer assembly approach, by immobilizing a layer of NEST on top of multilayers consisting of a polyelectrolyte (poly-L-lysine) and an enzyme (tyrosinase). The biosensor has a response time on the order of seconds and gives a concentration-dependent decrease in sensor output in response to a known NEST (and NTE) inhibitor. Potential applications of the biosensor include screening OP compounds for NTE inhibition and investigating the enzymology of wild-type and mutant forms of NTE. Although the development of a NEST biosensor was the primary purpose of this study, we found that the approach developed for NEST could also be extended to measure the activity of other esterases involved in neural processes, such as acetylcholinesterase (AChE) and butyrylcholinesterase (BChE). On the basis of measured sensitivities, phenyl valerate was the preferred substrate for NEST and BChE, whereas phenyl acetate was better for AChE.
authors.affiliation: Department of Chemical Engineering and Materials Science, Michigan State University, East Lansing, Michigan 48824, USA.
authors.forename: Neeraj
authors.initials: N
authors.lastname: Kohli
authors.forename: Devesh
authors.initials: D
authors.lastname: Srivastava
authors.forename: Jun
authors.initials: J
authors.lastname: Sun
authors.forename: Rudy J
authors.initials: RJ
authors.lastname: Richardson
authors.forename: Ilsoon
authors.initials: I
authors.lastname: Lee
authors.forename: Robert M
authors.initials: RM
authors.lastname: Worden
mesh_terms: D000110:Acetylcholinesterase / Q000032:analysis / Q000737:chemistry; D015374:Biosensing Techniques / Q000379:methods*; D002091:Butyrylcholinesterase / Q000032:analysis / Q000737:chemistry; D002265:Carboxylic Ester Hydrolases / Q000037:antagonists & inhibitors / Q000737:chemistry*; D020134:Catalytic Domain; D003217:Conductometry; D004566:Electrodes; D004800:Enzymes, Immobilized / Q000737:chemistry*; D006046:Gold / Q000737:chemistry; D006801:Humans; D049329:Nanostructures; D010446:Peptide Fragments / Q000737:chemistry; D010648:Phenylacetates / Q000737:chemistry; D014631:Valerates / Q000737:chemistry
chemical_list: D004800:Enzymes, Immobilized; D010446:Peptide Fragments; D010648:Phenylacetates; D014631:Valerates; C049867:phenyl valerate; D006046:Gold; D002265:Carboxylic Ester Hydrolases; C021859:neurotoxic esterase; D000110:Acetylcholinesterase; D002091:Butyrylcholinesterase; C025136:phenylacetic acid