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A light-up fluorescence assay for tumor cell detection based on bifunctional split aptamers

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Abstract

Light-up aptamers have attracted growing attention due to their advantages of being label-free and having low fluorescence background. In this work, we developed a light-up fluorescence assay for label-free detection of tumor cells based on a bifunctional split aptamer (BFSA) that contained two DNA strands (BFSA-a and BFSA-b). BFSA-a and BFSA-b were constructed by combining aptamers ZY11 and ThT.2-2, which could specifically bind to the tumor cell SMMC-7721 and activate the fluorescence of thioflavin T (ThT). A Helper strand was introduced to hybridize with BFSA-b, and then BFSA-a and BFSA-b were separated if the target cell was absent. Only when the target cell is present can BFSA-a approach and hybridize with BFSA-b due to the ‘induced-fit effect’, which made the Helper strand dissociate. Then ThT bound to BFSA and the fluorescence of ThT was activated. The results indicated that this fluorescence assay had a good linear response to the target cells in the range of 250–20 000 cells in 100 μL binding buffer; the lowest cell number actually detected was 125 cells in 100 μL buffer. This assay also displayed excellent selectivity and was successfully applied to detect target cells in 20% human serum samples. The design of bifunctional split aptamers realized no-washing, label-free, low-cost, one-step detection of tumor cells, which could generate detectable fluorescence signals just by mixing nucleic acid aptamers and fluorescent reporter molecules with target cells. Such a design of aptamer probes also has the potential to construct stimuli-responsive controlled drug delivery systems.

Graphical abstract: A light-up fluorescence assay for tumor cell detection based on bifunctional split aptamers

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Publication details

The article was received on 31 May 2018, accepted on 22 Jun 2018 and first published on 25 Jun 2018


Article type: Paper
DOI: 10.1039/C8AN01008K
Citation: Analyst, 2018, Advance Article
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    A light-up fluorescence assay for tumor cell detection based on bifunctional split aptamers

    Y. Sun, B. Yuan, M. Deng, Q. Wang, J. Huang, Q. Guo, J. Liu, X. Yang and K. Wang, Analyst, 2018, Advance Article , DOI: 10.1039/C8AN01008K

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