The Research Of Electrochemical Aptasensor For Detection Of Antibiotic Based On The Nanocomposites

This paper introduced the classification, sources and the harm of antibiotics in food. The function and characteristics of aptamer, which was used in electrochemical sensor for detection of antibiotics. Characteristics of nanocomposites and the application in the electrochemical aptasensor. And make the relevant improvement of electrochemical sensor for detection of antibiotics.Some researches were made as follows:1、We explored an amplification strategy which was based on graphene oxide-polyaniline(GO-PANI) and horseradish peroxidase(HRP) to construct the competitive aptasensor for ultrasensitive detection of oxytetracycline(OTC). In the protocol, the GO-PANI film was immobilized on the surface of the electrodes. Then, gold nanoparticles(AuNPs) were electrodeposited on the electrode surface using a constant potential stripping technique. The selected aptamer which had high affinity and specificity for OTC was used as a capture probe and labeled with HRP. The linear response to OTC concentration of the developed aptasensor was in the range of 4.0×10-6 mg L-1 to 1.0 mg L-1. The detection limit(LOD) of 2.3×10-6 mg L-1 was obtained(S/N=3). In addition to good repeatability and stability, the proposed aptamer sensor also showed the advantages of low background current and high sensitivity to examine OTC in real samples.2、The aptasensor was constructed by assembling graphene-polyaniline(GR-PANI) and polyamidoamine dendrimer-Au nanoparticle(PAMAM-Au) nanocomposites on the surfaces of a glass carbon electrode, which as electrode materials exhibited excellent charge-transport property and loading capacity of biomolecules. Followed by the sandwich-type specific identification, kanamycin detection was realized by outputting a redox current from electro-reduction reaction of H2O2 catalyzed by HRP. It was demonstrated that the developed strategy had a wide linear response range from 5×10-6-4×10-2 μg m L-1 and the low detection limit of 4.6×10-6 μg m L-1. Additionally, this aptasensor had the advantages in its low cost, high sensitivity, and superb specificity. Thus, it might provide a useful tool for kanamycin determination and related food safety analysis and clinical diagnosis.3、In this work, we demonstrated a novel sandwich-type electrochemical aptasensor for sensitive and selective detection of antibiotic oxytetracycline(OTC). The strategy was based on graphene-three dimensional nanostructure gold nanocomposite modified glassy carbon electrode(GR-3D Au/GCE) and aptamer-AuNPs-horseradish peroxidase(HRP) nanprobes as signal amplification. In this strategy, the GR-3D Au film was prepared only with one-step electrochemical coreduction with graphite oxide(GO) and HAuCl4 at cathodic potentials with the ability of enhancing the electron transfer and loading capacity of biomolecules. The aptamer and HRP modified Au nanoparticles provide high affinity and ultrasensitive electrochemical probe with excellent specificity for OTC. At the concentration of 5×10-13 to 2×10-6 g mL-1, OTC could be determined with a detection limit of 4.98×10-13 g mL-1. Additionally, this aptasensor had the advantages in high sensitivity, superb specificity and showed good recovery in related food safety analysis and clinical diagnosis.