Wang J, Tan L, Bi W, Shen H, Li D, Yu Z, Gan N. Ultrasensitive microfluidic immunosensor with
stir bar enrichment for point-of-care test of Staphylococcus aureus in foods triggered by DNAzyme-assisted click reaction.
Food Chem 2022;
378:132093. [PMID:
35032807 DOI:
10.1016/j.foodchem.2022.132093]
[Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Revised: 01/03/2022] [Accepted: 01/05/2022] [Indexed: 12/11/2022]
Abstract
This work demonstrated an ultrasensitive and simple microfluidic immunosensor for point-of-care test of Staphylococcus aureus (S. aureus) based on the stir bar enrichment and DNAzyme-assisted click reaction. Initially, S. aureus was enriched by the 4-mercaptophenylboronic acid-functionalized stir bar. The yolk antibody (immunoglobulin Y) and copper-labeled polydopamine nanoparticles were then specifically conjugated with the captured target. The Cu(II) was released under acidic conditions and effectively catalyzed the copper-catalyzed azide-alkyne cycloaddition (CuAAC) between the alkyne group-labeled DNAzyme and the streptavidin-biotin-azido with the assistance of DNAzyme. Finally, the DNAzyme-streptavidin complexes were detected by microfluidic chips to quantify S. aureus. Under optimum conditions, this immunosensor showed good detection performances toward S. aureus within 10 to 2.5 × 104 CFU/mL with a limit of detection of 3 CFU/mL. Moreover, the satisfying detection results of real samples of animal origin also implied that this immunosensor owned great potential in practical applications.
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