Rapid identification and quantitation of the viable cells of Lactobacillus casei in fermented dairy products using an aptamer-based strategy powered by a novel cell-SELEX protocol

Abstract

An aptamer-based strategy was developed for qualitative and quantitative analysis of viable Lactobacillus casei in dairy products. Three highly specific aptamers for L. casei were obtained using systematic evolution of ligands by exponential enrichment protocol using the whole bacterium cell as the target (cell-SELEX) facilitated by polyethyleneglycol and chitosan modified graphene oxide and complementary ring-mediated rolling circle amplification. Two aptamers, one for separating and enriching the L. casei cells and the other for generating fluorescence signals, were employed to develop an aptamer-based strategy, which was demonstrated for the selective detection of L. casei in commercial dairy drinks, with a dynamic range of 10 5 to 10 9 cfu/mL. Viable and nonviable L. casei cells could be discriminated based on the significant difference in fluorescence intensity. This established strategy is of high selectivity and sensitivity, and can be used for rapid analysis of viable L. casei in quality control and food surveillance areas.

Moving towards Personalized Medicine—The Broad Use of Aptamers for Targeted Theranostic

“…Aptamers can be designed to specifically bind to the surface molecules or antigens of certain bacteria or other microorganisms, facilitating the identification and quantification of those organisms [115]. This method can be particularly useful in identifying and monitoring specific pathogenic or beneficial microorganisms in complex microbial communities, with studies by Hu et al and Song et al describing this novel approach in strains like Bifidobacterium bifidum (CCFM641-5) and Lactobacillus casei, at the same time, demonstrating the potential of aptamer-based strategies for the rapid and accurate detection and quantification of bacteria in food products [116,117].…”