title: A versatile activatable fluorescence probing platform for cancer cells in vitro and in vivo based on self-assembled aptamer/carbon nanotube ensembles.
abstract: Activatable aptamer probes (AAPs) have emerged as a promising strategy in cancer diagnostics, but existing AAPs remain problematic due to complex design and synthesis, instability in biofluids, or lack of versatility for both in vitro and in vivo applications. Herein, we proposed a novel AAP strategy for cancer cell probing based on fluorophore-labeled aptamer/single-walled carbon nanotube (F-apt/SWNT) ensembles. Through π-stacking interactions and proximity-induced energy transfer, F-apt/SWNT with quenched fluorescence spontaneously formed in its free state and realized signal activation upon targeting surface receptors of living cells. As a demonstration, Sgc8c aptamer was used for in vitro analysis and in vivo imaging of CCRF-CEM cancer cells. It was found that self-assembled Cy5-Sgc8c/SWNT held robust stability for biological applications, including good dispersity in different media and ultralow fluorescence background persistent for 2 h in serum. Flow cytometry assays revealed that Cy5-Sgc8c/SWNT was specifically activated by target cells with dramatic fluorescence elevation and showed improved sensitivity with as low as 12 CCRF-CEM cells detected in mixed samples containing ~100,000 nontarget cells. In vivo studies confirmed that specifically activated fluorescence was imaged in CCRF-CEM tumors, and compared to "always on" probes, Cy5-Sgc8c/SWNT greatly reduced background signals, thus resulting in contrast-enhanced imaging. The general applicability of the strategy was also testified by detecting Ramos cells with aptamer TD05. It was implied that F-apt/SWNT ensembles hold great potential as a simple, stable, sensitive, specific, and versatile activatable platform for both in vitro cancer cell detection and in vivo cancer imaging.
authors.affiliation: State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, College of Biology, Hunan University , Key Laboratory for Bio-Nanotechnology and Molecular Engineering of Hunan Province, Changsha 410082, China.
authors.forename: Lv'an
authors.initials: L
authors.lastname: Yan
authors.forename: Hui
authors.initials: H
authors.lastname: Shi
authors.forename: Xiaoxiao
authors.initials: X
authors.lastname: He
authors.forename: Kemin
authors.initials: K
authors.lastname: Wang
authors.forename: Jinlu
authors.initials: J
authors.lastname: Tang
authors.forename: Mian
authors.initials: M
authors.lastname: Chen
authors.forename: Xiaosheng
authors.initials: X
authors.lastname: Ye
authors.forename: Fengzhou
authors.initials: F
authors.lastname: Xu
authors.forename: Yanli
authors.initials: Y
authors.lastname: Lei
mesh_terms: D000818:Animals; D052157:Aptamers, Nucleotide / Q000737:chemistry*; D002232:Carbocyanines / Q000737:chemistry; D045744:Cell Line, Tumor; D005434:Flow Cytometry; D005456:Fluorescent Dyes / Q000737:chemistry*; D006801:Humans; D051379:Mice; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D018613:Microscopy, Confocal; D037742:Nanotubes, Carbon / Q000737:chemistry*; D009369:Neoplasms / Q000378:metabolism / Q000473:pathology*; D010084:Oxidation-Reduction; D013050:Spectrometry, Fluorescence; D059008:Time-Lapse Imaging; D014183:Transplantation, Heterologous
chemical_list: D052157:Aptamers, Nucleotide; D002232:Carbocyanines; D005456:Fluorescent Dyes; D037742:Nanotubes, Carbon; C085321:cyanine dye 5