Abstract
Impedimetric analysis method is an important tool for food safety detection. In this work, a novel impedimetric microfluidic analysis system consisted of a printed gold electrode chip and a microfluidic flow cell was developed for sensitive and selective detection of transgenic protein Cry1Ab. Anti-Cry1Ab aptamer coated magnetic beads were used to recognize transgenic protein Cry1Ab and form Cry1Ab-aptamer modified magnetic beads. After separation, the obtained Cry1Ab-aptamer modified magnetic beads were dissolved in 0.01 M mannitol and followed by injection into the microfluidic flow cell for impedimetric measurement. At the frequency of 358.3 Hz, the impedance signal shows a good linearity with the concentrations of Cry1Ab protein at a range from 0 to 0.2 nM, and the detection limit is 0.015 nM. The results demonstrate that the impedimetric microfluidic analysis system provides an alternative way to enable sensitive, rapid and specific detection of transgenic protein Cry1Ab.
Highlights
In recent years, exogenous Bacillus thuringiensis (Bt) gene is always introduced into crops by genetic modification technology to produce a serial of Bt proteins (Cry1Aa, Cry1Ab, Cry1Ac and Cry1B) to achieve the goal of insect resistance, since Bt is the most important insecticide in the field of biological control
The relative standard deviations (RSD) of the impedance signal of the impedimetric microfluidic analysis system at frequency of 358.3 Hz for 5 repeated cycles in DI water, 0.01 M mannitol, and 1 mM K3[Fe(CN)6] are less than 0.9%, 2.3%, and 3.2%. These results indicated that the impedimetric microfluidic analysis system has excellent stability and reproducibility
This research focuses on detecting the transgenic protein Cry1Ab based on microfluidic impedimetric analysis method by using aptamer modified magnetic beads as bio-recognition element
Summary
Exogenous Bacillus thuringiensis (Bt) gene is always introduced into crops by genetic modification technology to produce a serial of Bt proteins (Cry1Aa, Cry1Ab, Cry1Ac and Cry1B) to achieve the goal of insect resistance, since Bt is the most important insecticide in the field of biological control. Impedimetric biosensing method can be an ideal alternative due to its excellent advantages including high sensitivity, rapidity, ease to miniaturization, and low cost[9,10,11], which has been used for the detection of various targets including DNA12,13, proteins[14,15], pesticide[16,17], heavy metal ions[18], and bacteria[19] In these detection methods, the bio-recognition elements, i.e., DNA20,21, aptamer[22,23,24,25] or antibody[26,27], are immobilized on the surface of transducer to react with the targets, which produce the impedance signal[28]. Compared to the previously reported methods for Cry1Ab detection, our impedimetric biosensing method exhibits higher sensitivity and shorter assay time
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