title: Ultrasensitive colorimetric carcinoembryonic antigen biosensor based on hyperbranched rolling circle amplification.
abstract: In this study, a hyperbranched rolling circle amplification (HRCA)-based colorimetric biosensor for carcinoembryonic antigen (CEA) is developed with high sensitivity and specificity. A CEA aptamer can bind with its target (CEA) to form a complex due to their high affinity, and the introduced CDNA cannot hybridize with the aptamer. Thus, free CDNA can propagate the HRCA reaction to form a large number of single-stranded DNA (ss-DNA). ss-DNA can be easily adsorbed onto AuNPs and prevent salt-induced AuNPs aggregation, which causes the change in the color of the system. It is found that the absorbance intensity ratio (A520/A660) has a linear relationship with the concentration of the target in the range of 5 pM-0.5 nM, and the detection limit is as low as 2 pM (S/N = 3).
authors.affiliation: Henan Provincial People's Hospital, Zhengzhou, Henan 450003, China.
authors.forename: Kai
authors.initials: K
authors.lastname: Liang
authors.forename: Shuiting
authors.initials: S
authors.lastname: Zhai
authors.forename: Zhidong
authors.initials: Z
authors.lastname: Zhang
authors.forename: Xiaoyang
authors.initials: X
authors.lastname: Fu
authors.forename: Jingwei
authors.initials: J
authors.lastname: Shao
authors.forename: Zhenyu
authors.initials: Z
authors.lastname: Lin
authors.forename: Bin
authors.initials: B
authors.lastname: Qiu
authors.forename: Guo-nan
authors.initials: GN
authors.lastname: Chen
mesh_terms: D052157:Aptamers, Nucleotide / Q000737:chemistry*; D014408:Biomarkers, Tumor / Q000032:analysis; D015374:Biosensing Techniques / Q000379:methods*; D002272:Carcinoembryonic Antigen / Q000032:analysis*; D003124:Colorimetry / Q000379:methods; D004277:DNA, Single-Stranded / Q000737:chemistry; D006046:Gold / Q000737:chemistry; D006801:Humans; D057230:Limit of Detection; D053768:Metal Nanoparticles / Q000737:chemistry; D021141:Nucleic Acid Amplification Techniques / Q000379:methods*
chemical_list: D052157:Aptamers, Nucleotide; D014408:Biomarkers, Tumor; D002272:Carcinoembryonic Antigen; D004277:DNA, Single-Stranded; D006046:Gold