Acetylcholinesterase biosensor based on multi-walled carbon nanotubes-SnO2-chitosan nanocomposite

Abstract

A sensitive amperometric acetylcholinesterase (AChE) biosensor was developed based on the nanocomposite of multi-walled carbon nanotubes (MWCNTs), tin oxide (SnO2) nanoparticles and chitosan (CHIT). Acetylcholinesterase (AChE) and Nafion were immobilized onto the nanocomposite film to prepare AChE biosensor for pesticide residues detection. The morphologies and electrochemistry properties of the surface modification were investigated using cyclic voltammetry, differential pulse voltammetry, and scanning electron microscopy, respectively. Compared with individual MWCNTs-CHIT, SnO2-CHIT and bare gold electrode, this nanocomposite showed the most obvious electrochemical signal in the presence of [Fe(CN)6](3-/4-) as a redox couple. Incorporating MWCNTs and SnO2 into 0.2% CHIT solution can promote electron transfer, enhance the electrochemical response, and improve the microarchitecture of the electrode surface. All variables involved in the preparation process and analytical performance of the biosensor were optimized. Under optimized conditions, the AChE biosensor exhibited a wide linear range from 0.05 to 1.0 × 10(5 )μg/L and with a detection limit for chlorpyrifos was 0.05 μg/L. Based on the inhibition of pesticides on the AChE activity, using chlorpyrifos as model pesticide, the proposed biosensor exhibited a wide range, low detection limit, good reproducibility, and high stability. Using cabbages, lettuces, leeks, and pakchois as model samples, acceptable recovery of 98.7-105.2% was obtained. The proposed method was proven to be a feasible quantitative method for chlorpyrifos analysis, which may open a new door ultrasensitive detection of chlorpyrifos residues in vegetables and fruits.

Recent Advances in the Fabrication and Application of Screen-Printed Electrochemical (Bio)Sensors Based on Carbon Materials for Biomedical, Agri-Food and Environmental Analyses

“…The adherence of the enzyme molecules onto electrode surfaces without denaturing the enzyme or blocking the active site has been a critical challenge for researchers. Various strategies have been used to immobilise AChE onto the electrode surface, including adsorption [66], entrapment [67,68] and cross-linking [69,70] amongst others. In an extensive study of immobilisation techniques Pohanka et al [71] concluded that glutaraldehyde cross-linking was the preferred method and has proved to be a useful method for a range of electrode materials, such as gold [72], platinum [73] and carbon SPEs [74].…”

“…Carbon remains the most common electrode material (Table 7) and has been used in the detection of OPs in sub-ppb concentrations [63,67,73,74], although gold [72] and platinum [75] have also been successfully used in the analysis of ppb levels of OPs.…”

“…Multi-walled carbon nanotubes (MWCNT) [67] and single-walled carbon nanotubes (SWCNT) [78] have also been examined contributing to the detection of selected OPs at ppb levels. Gan et al [79] successfully detected dimethoate at ppt levels with the use of magnetic composite nanoparticles in buffer and vegetable extracts; however other strategies have consistently resulted in the detection of low ppb concentrations of OPs.…”

“…Gan et al [79] successfully detected dimethoate at ppt levels with the use of magnetic composite nanoparticles in buffer and vegetable extracts; however other strategies have consistently resulted in the detection of low ppb concentrations of OPs. An example of his can be observed in the development of electric eel AChE-based biosensors by Chen et al [67] who incorporated both MWCNT and tin oxide onto the surface of SPCEs. The analysis of simple vegetable extracts using these sensors with cyclic voltammetry resulted in a detection of 50 µg/L chlorpyrifos.…”

Cholinesterase-based biosensors

“…Chen et al developed a sensitive amperometric AChE biosensor based on nanocomposite of multi-walled carbon nanotubes, tin oxide nanoparticles and chitosan. This biosensor was used for pesticide residue detections 156 .…”