Electrochemical immunosensor for multiplexed detection of food-borne pathogens using nanocrystal bioconjugates and MWCNT screen-printed electrode

Abstract

a b s t r a c tBacterial food poisoning is an ever-present threat that can be prevented with proper care and handling of food products. A disposable electrochemical immunosensor for the simultaneous measurements of common food pathogenic bacteria namely Escherichia coli O157:H7 (E. coli), campylobacter and salmonella were developed. The immunosensor was fabricated by immobilizing the mixture of anti-E. coli, anticampylobacter and anti-salmonella antibodies with a ratio of 1:1:1 on the surface of the multiwall carbon nanotube-polyallylamine modified screen printed electrode (MWCNT-PAH/SPE). Bacteria suspension became attached to the immobilized antibodies when the immunosensor was incubated in liquid samples. The sandwich immunoassay was performed with three antibodies conjugated with specific nanocrystal (␣-E. coli-CdS, ␣-campylobacter-PbS and ␣-salmonella-CuS) which has releasable metal ions for electrochemical measurements. The square wave anodic stripping voltammetry (SWASV) was employed to measure released metal ions from bound antibody nanocrystal conjugates. The calibration curves for three selected bacteria were found in the range of 1 × 10 3 -5 × 10 5 cells mL −1 with the limit of detection (LOD) 400 cells mL −1 for salmonella, 400 cells mL −1 for campylobacter and 800 cells mL −1 for E. coli. The precision and sensitivity of this method show the feasibility of multiplexed determination of bacteria in milk samples.

Electrochemical Immunoassay ofEscherichia coliO157:H7 Using Ag@SiO2Nanoparticles as Labels

“…This value is markedly smaller than 5000 [20], 3270 cfu/mL [2], 1200 [21], 150 cfu/mL [9], 83.7 cfu/mL [22], 30 cfu/mL [4], and 22 cfu/mL [8], and higher than 7 cfu/mL [23], 3 cfu/mL [24], and 2 cfu/mL [25]. The detection limit of 4.5 fg/ μ L [26] and 800 cells/mL [27] was also realized. The results implied that this detecting approach exhibited a lower detection limit.…”

Electrochemical immunosensor for Enterobacter sakazakii detection based on electrochemically reduced graphene oxide–gold nanoparticle/ionic liquid modified electrode

“…ACCEPTED MANUSCRIPT 13 sakazakii were also investigated. The effect of incubation temperature on the ΔIp was studied in the temperature range from 24 to 36 ℃.…”

“…Currently, amperometric immunosensor has been widely studied for pathogen detection with convenience and simple preparation [12][13][14][15]. To construct an useful electrochemical immunosensor, working electrode should have large surface areas to load capture molecules, good biocompatibility to preservate biological activity of bimolecular and excellent conductivity to efficiently transport electron [16].…”

Enhancing detection sensitivity of piezoelectric plate sensor by increasing transverse electromechanical coupling constant

“…In the past two decades, label-free alternatives have been studied by many authors. Some of the examples include quartz crystal microbalance (QCM), 1-3 surface acoustic wave (SAW) devices, 4,5 surface plasmon resonance (SPR), 6,7 silicon microcantilevers, [8][9][10][11] electrochemical sensors, [12][13][14] nanotube and nanowire biosensors. [15][16][17] Although these label-free methods can be rapid and simpler, they generally lack the sensitivity of ELISA.…”