The project belongs to the biosensor discipline. It is a successful application of nano-electrochemical biosensing in the field of food safety testing.
The frequent occurrence of "clenbuterol incidents" poses challenges to the ability to detect harmful residues in food, especially the on-site inspection at the source feeding link, and requires more accurate and sensitive on-site quantitative detection methods. Most traditional methods are difficult to achieve on-site quantification, and biosensors have shown great development potential in terms of sensitivity, portability and detection cost, providing a good opportunity to respond to on-site detection of harmful residues in food. However, in order to achieve highly sensitive quantification of non-processed or low-processed biological samples on site, a series of problems still need to be overcome: 1) miniaturization and portability;2) higher sensitivity and specificity;3) traceability of results and reliability of results., practicality of the method and promotion and application.
The project aims at on-site quantitative detection of harmful residues in food, and carries out technology development including nano assembly, biomolecule loading, electrochemical chip miniaturization, and research and development of related biomatrix standards. Specific project content:
First, preparation of nanocomposite films: A vacuum suction filtration method was invented for the first time, and key conditions such as Nafion mass fraction and suction filtration speed were optimized. The prepared nano film has good flexibility, can withstand 1000 bends, is super-hydrophobic, and has good electrical conductivity. It has achieved good performance in the electrochemical detection process of NADH coenzyme, and the redox potential has been effectively reduced. 670mV, laying a solid foundation for biosensing applications. The main results were published in Nano lett, the world's top journal for nanoresearch. 2008,8(12),4454 (IF 13.025)。
Second, the assembly of biomolecules on the surface of carbon nanotubes. The biomolecule binding process of carbon nanotubes was studied, and a new multi-labeled nanoprobe was proposed. Horseradish peroxidase (HRP) and goat anti-mouse IgG (secondary antibody) were successfully assembled on the surface of multi-walled carbon nanotubes (MWNT). The nanoprobe obtained in this way can be applied to almost all sandwich immunoassay platforms. It uses a surface-printed carbon electrode array to achieve ultra-high detection sensitivity and can detect 5pg/mL PSA and 8pg/mL IL-8, which can be detected simultaneously with dual target substances. The main results were published in Biosens.Bioelectron. 2011,30,93 (IF 5.429)。
Third, based on previous research, a miniaturized electrochemical chip was proposed to achieve quantitative detection of harmful residues in food on site. For the first time, a centrifugal separation method was invented to purify composite materials, improve protein binding efficiency, and improve specificity by blocking blank sites on the interface. It has achieved on-site rapid quantitative detection of harmful residues such as clenbuterol hydrochloride and ractopamine, and the sensitivity has been improved by an order of magnitude. The main results are also published in Biosens.Bioelectron. 2011, 28.308 (IF 5.429).
Fourth, in order to ensure the reliability of quantitative test results, we have developed supporting matrix reference materials, including four clenbuterol hydrochloride reference materials in pig urine lyophilized powder. We conducted scientific and strict inspections on uniformity and stability, and organized 8 laboratories have jointly participated in the joint determination of standard materials, and have obtained national standard material certificates (GBW(E)090477, GBW(E) 090478, GBW (E) 090479, GBW(E)090480).
Starting from the core basic technology, the project studied a set of nanomaterial-assisted chip-based electrochemical biosensing methods, and successfully applied them to accurately quantify clenbuterol hydrochloride in field samples. Published 9 articles, with a total of 45 impact factors, a total of 144 citations, authorized 3 invention patents, and key technologies such as chip miniaturization and nanomaterials, providing important theoretical and experimental basis for the development of the field of biosensing. The testing method has been promoted and applied in agricultural health supervision departments to achieve on-site portable testing and improve the detection efficiency and accuracy of illegal veterinary drugs; the standard materials developed promote method research and are applied in kit production and food safety testing laboratories to establish a good value traceability approach to ensure the reliability and comparability of results.