A light-up fluorescence assay for tumor cell detection based on bifunctional split aptamers. Issue 15 (12th July 2018)

• Record Type: Journal Article
• Authors: Sun, Yuqiong; Yuan, Baoyin; Deng, Meitao; Wang, Qing; Huang, Jin; Guo, Qiuping; Liu, Jianbo; Yang, Xiaohai; Wang, Kemin
• Is Part Of: Analyst. Volume 143:Issue 15(2018)
• Page Start: 3579
• Page End: 3585
• Publication Date: 2018-07-12
• Subjects: Chemistry, Analytic -- Periodicals; 543
• DOI: 10.1039/c8an01008k
• Languages: English
• ISSNs: 0003-2654

Abstract

Abstract : Truncating, splitting and fusing of two aptamers for label-free and one-step fluorescence detection of tumor cells. 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.