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. 2018 Jun 5;19(6):1671. doi: 10.3390/ijms19061671

Figure 4.

Figure 4

DNA gelation-based cloaking and decloaking of circulating tumor cells (CTCs). (a) The aptamer-initiator biblocks (red line) are able to specifically bind the epithelial cell adhesion molecule (EpCAM) on the cell surface, which can then trigger the aptamer-trigger clamped hybridization chain reaction (atcHCR) to assemble the DNA hydrogel. Adenosine triphosphate (ATP) is used to destroy the DNA hydrogel containing ATP-responsive regions (purple line); (b) DNA hairpins H1 and H2 were trapped in a metastable state. Without a DNA initiator, H1 and H2 cannot hybridize. With a DNA initiator, H1 is opened and triggers the subsequent hybridization chain reaction; (c) Confocal images of aptamer-initiator biblocks (red) colocalized with 3,3′-dioctadecyloxacarbocyanine perchlorate (DiO) stained lipids on the cell membrane (green); (d) 3D stack of MCF-7 cells cloaked in a DNA hydrogel with FDA staining in green, showing multilayered cells in the hydrogel. Stack height: 40 μm; (e) By adding ATP, MCF-7 cells were released and dispersed in solution. Reproduced with permission from Ref. [39] Copyright 2017 American Chemical Society.