关键词: 动物源性成分检测, 不对称PCR, G-四联体, 生物传感器, 羊

Abstract: In recent years, the phenomenon of meat adulteration has become a hot topic in society. Identification of animal-derived components in livestock products is one of the important strategies to fight against meat adulteration. Based on this situation, a colorimetric biosensor based on G-quadruplex was established to identify sheep-derived components in meat products by using asymmetric PCR (As-PCR) and combining with the functional characteristics of G-quadruplex. Using sheep genomic DNA as template, and adding a reverse complementary sequence of G-quadruplex to the 5′ end of the restrictive forward primer, a large amount of single strand DNA (ssDNA) containing G-quadruplex sequence was amplified by As-PCR, and then the generated ssDNA combined with hemin under the action of K+ to form the G-quadruplex-hemin complex with DNAzyme activity. The compound could catalyze the reaction of H2O2 and 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS2-) to generate a green reaction product, and the result could be visually observed without conventional detection steps, such as electrophoresis, sequencing, etc. By optimizing the reaction conditions and system of As-PCR, the biosensor could realize accurate and rapid identification of sheep-derived components in meat products, and it could stably detect the minimum mass fraction of sheep-derived components in mixed meat samples to be 5%. The colorimetric biosensor based on G-quadruplex established by the research had the advantages of simplicity, sensitivity, visualization, low cost, etc. And it could be used for detecting animal-derived components in meat products, and it provided strong technical support for the safety detection of meat products.

Key words: detection of animal-derived components, asymmetric PCR, G-quadruplex, biosensor, sheep