title: Visual and highly sensitive detection of cancer cells by a colorimetric aptasensor based on cell-triggered cyclic enzymatic signal amplification.
abstract: Rapid and efficient detection of cancer cells at their earliest stages is one of the central challenges in cancer diagnostics. We developed a simple, cost-effective, and highly sensitive colorimetric method for visually detecting rare cancer cells based on cell-triggered cyclic enzymatic signal amplification (CTCESA). In the absence of target cells, hairpin aptamer probes (HAPs) and linker DNAs stably coexist in solution, and the linker DNA assembles DNA-AuNPs, producing a purple solution. In the presence of target cells, the specific binding of HAPs to the target cells triggers a conformational switch that results in linker DNA hybridization and cleavage by nicking endonuclease-strand scission cycles. Consequently, the cleaved fragments of linker DNA can no longer assemble into DNA-AuNPs, resulting in a red color. UV-vis spectrometry and photograph analyses demonstrated that this CTCESA-based method exhibited selective and sensitive colorimetric responses to the presence of target CCRF-CEM cells, which could be detected by the naked eye. The linear response for CCRF-CEM cells in a concentration range from 10(2) to 10(4) cells was obtained with a detection limit of 40 cells, which is approximately 20 times lower than the detection limit of normal AuNP-based methods without amplification. Given the high specificity and sensitivity of CTCESA, this colorimetric method provides a sensitive, label-free, and cost-effective approach for early cancer diagnosis and point-to-care applications.
authors.affiliation: Department of Chemistry, Fudan University , Shanghai 200433, P. R. China.
authors.forename: Xianxia
authors.initials: X
authors.lastname: Zhang
authors.forename: Kunyi
authors.initials: K
authors.lastname: Xiao
authors.forename: Liwei
authors.initials: L
authors.lastname: Cheng
authors.forename: Hui
authors.initials: H
authors.lastname: Chen
authors.forename: Baohong
authors.initials: B
authors.lastname: Liu
authors.forename: Song
authors.initials: S
authors.lastname: Zhang
authors.forename: Jilie
authors.initials: J
authors.lastname: Kong
mesh_terms: D000251:Adenosine Triphosphatases / Q000737:chemistry; D000818:Animals; D052157:Aptamers, Nucleotide / Q000737:chemistry; D015374:Biosensing Techniques / Q000379:methods*; D045744:Cell Line, Tumor; D002477:Cells / Q000737:chemistry*; D003124:Colorimetry; D004247:DNA / Q000737:chemistry; D006046:Gold / Q000737:chemistry; D006801:Humans; D053768:Metal Nanoparticles; D051379:Mice; D009369:Neoplasms / Q000737:chemistry*; D052156:SELEX Aptamer Technique / Q000379:methods*; D013056:Spectrophotometry, Ultraviolet
chemical_list: D052157:Aptamers, Nucleotide; D006046:Gold; D004247:DNA; D000251:Adenosine Triphosphatases