Acetylcholinesterase Sensor Based on Polyelectrolyte Complexes with DNA Inclusion for the Determination of Reversible Inhibitors

Abstract

The acetylcholinesterase (AChE) biosensor has been developed for the determination of reversible inhibitors applied in the Alzheimer's disease therapy, i. e., Huperzine A (HupA) and galantamine (Gal). For this purpose, glassy carbon electrode (GCE) was first modified with carbon black (CB) and Co phthalocyanine and then polyelectrolyte complex was self‐assembled on its surface by drop casting of reactants and washing. To extend the stability and improve biosensor performance, it was proposed for the first time to use DNA as polyanion in the complex assembly. The DNA showed higher charge density than conventional polyelectrolytes and stabilized the surface coating by adsorption of higher enzyme amount and prevention of its leaching during the biosensor operation. Complex formation and the influence of structural factors were monitored with surface plasmon resonance. Kinetic study showed mixed inhibition of the enzyme within micro‐ and nanomolar range of inhibitor concentrations. The AChE biosensor showed limit of detection of HupA equal to 0.9 and that of Gal to 70 nM. The sensitivity of drug determination was found to be close or better than that of the AChE biosensors previously reported in the literature. The biosensor was tested on the sample of artificial urine and showed 102 % recovery of the drugs determination.

Flow-Through Acetylcholinesterase Sensor with Replaceable Enzyme Reactor

“…If the electrode was covered with CB and P[5]A, the addition of the thiocholine resulted in an increase in the peaks ( a 1 , c 1 ) attributed to the P[5]A and the appearance of a new peak ( a 2 ) related to the oxidation of thiocholine. The latter one corresponds to the 0.25 V and coincides with the conditions of the reactions reported earlier in similar research [ 23 , 24 ]. However, despite the significant difference in the peak currents, the voltammograms obtained in the presence of thiocholine were unstable and appropriate signals rapidly decreased in a series of consecutive measurements from the same solution.…”

“…Due to a wide variety of species exerting the anticholinesterase effect, AChE biosensors were proposed as indicators of general pollution of the environment [ 17 ] and for detection of heavy metals [ 18 ], surfactants [ 19 ], fluorides [ 20 ] and organic solvents [ 21 , 22 ] exerting a non-specific inhibitory effect. Recently, AChE biosensors were also successfully utilized for the determination of reversible inhibitors, e.g., anti-dementia drugs [ 23 , 24 ] and aflatoxins [ 25 , 26 ].…”

Polyelectrolytes Assembly: A Powerful Tool for Electrochemical Sensing Application

“…The immobilization of the AChE enzyme through the non-covalent immobilization (by dropcasting) of the enzyme solution onto a previously modified GCE for the determination of reversible AChE inhibitors was reported by Davletshina et al [78]. This immobilization was based on weak electrostatic inter-molecular interaction between a PE multilayer film prepared using the LbL method Reprinted from [75] with permission from the Elsevier.…”

Acetylcholinesterase Biosensor Based on Reduced Graphene Oxide – Carbon Black Composite for Determination of Reversible Inhibitors

“…This assumes stricter requirements to the enzyme immobilization and signal detection mode because the active site of immobilized enzyme should retain its accessibility for both reactants and any changes in the microenvironment affect the inhibition degree calculated from the biosensor signal changes. Previously we have shown the importance of the enzyme matrix and assessed the performance of the AChE biosensors based on various supports and immobilization protocols [23][24][25].…”