Team:DUT China A/Description

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In order to address the difficulties on recognition, visualization, and capture of living CTCs with high purity and integrity, we constructed a multifunctional DNA hydrogel like a prison CELL capsuling CTCs, and defined this new platform as “cell in CELL” (CiC).

With this strategy, clinics may have a new way to understand the condition of the patients while the researchers can have the opportunity to obtain the CTCs with high biological activity.

Our strategy contains three vital parts, the fluorescence-labeled ssDNA aptamers, switches and DNA hydrogels.

(i) The fluorescence-labeled ssDNA aptamers specifically binds to the receptors of CTCs and visualize them.
(ii) Once successfully targeting CTCs, the ssDNA aptamers will expose the sticky end further for triggering the adhesion of sticky-end pairing ssDNA. This process is the switch of the formation of DNA hydrogel around CTCs.
(iii) The pairing ssDNA can induce two sequential processes: (a) a rolling circle amplification (RCA, or R) followed by (b) a multi-primed chain amplification (MCA, or M), making CTCs enveloped with hydrogels. This step can enlarge the size of CTCs for centrifugal isolation. After being treated with exonucleases, CTCs are released intactly and with high activity.

Compared to other methods, our strategy is more superior in these ways.
First, adopting the unique combination of RCA and MCA, we can achieve a controllable size and morphology of the DNA hydrogel.
Second, CTCs are extremely rare and they are same in size and similar in shape as the leucocytes. Our device can magnificates the difference and makes the subsequent isolation convenient.
Third, the traditional capture methods based on DNA hydrogel monomers consume a big amount of nucleate acid. Our strategy is able to cut down the costs.

Citation:
  • [1] HASSAN E M, WILLMORE W G, DEROSA M C. Aptamers: Promising Tools for the Detection of Circulating Tumor Cells [J]. Nucleic Acid Therapeutics, 2016, 26(6): 335.
  • [2] JAYASENA S D. Aptamers: an emerging class of molecules that rival antibodies in diagnostics [J]. Clinical Chemistry, 1999, 45(9): 1628.
  • [3] SONG P, YE D, ZUO X, et al. DNA Hydrogel with Aptamer-Toehold-Based Recognition, Cloaking, and Decloaking of Circulating Tumor Cells for Live Cell Analysis [J]. Nano Letters, 2017, 17(9): 5193-8.