title: Aptamer-based colorimetric detection of proteins using a branched DNA cascade amplification strategy and unmodified gold nanoparticles.
abstract: A branched DNA amplification strategy was employed to design a colorimetric aptameric biosensor using unmodified gold nanoparticles (AuNPs). First, a programmed DNA dendritic nanostructure was formed using two double-stranded substrate DNAs and two single-stranded auxiliary DNAs as assembly components via a target-assisted cascade amplification reaction, and it was then captured by DNA sensing probe-stabilized AuNPs. The release of sensing probes from AuNPs led to the formation of unstable AuNPs, promoting salt-induced aggregation. By integrating the signal amplification capacity of the branched DNA cascade reaction and unmodified AuNPs as a sensing indicator, this amplified colorimetric sensing strategy allows protein detection with high sensitivity (at the femtomole level) and selectivity. The limit of detection of this approach for VEGF was lower than those of other aptamer-based detection methods. Moreover, this assay provides modification-free and enzyme-free protein detection without sophisticated instrumentation and might be generally applicable to the detection of other protein targets in the future.
authors.affiliation: Institute of Biomedical Engineering, National Taiwan University, Taipei 106, Taiwan, ROC.
authors.forename: Chia-Chen
authors.initials: CC
authors.lastname: Chang
authors.affiliation: Department of Obstetrics and Gynecology, Mackay Memorial Hospital, Taipei 104, Taiwan, ROC; Department of Medicine, Mackay Medical College, Taipei 252, Taiwan, ROC; Mackay Junior College of Medicine, Nursing, and Management, Taipei 112, Taiwan, ROC.
authors.forename: Chen-Yu
authors.initials: CY
authors.lastname: Chen
authors.affiliation: Institute of Biomedical Engineering, National Taiwan University, Taipei 106, Taiwan, ROC.
authors.forename: Tsung-Liang
authors.initials: TL
authors.lastname: Chuang
authors.affiliation: Institute of Biomedical Electronic and Bioinformatics, National Taiwan University, Taipei 106, Taiwan, ROC.
authors.forename: Tzu-Heng
authors.initials: TH
authors.lastname: Wu
authors.affiliation: Department of Internal Medicine, National Taiwan University Hospital and College of Medicine, Taipei 100, Taiwan, ROC.
authors.forename: Shu-Chen
authors.initials: SC
authors.lastname: Wei
authors.affiliation: Department of Biomedical Engineering, School of Medicine, Tsinghua University, Beijing 100084, PR China.
authors.forename: Hongen
authors.initials: H
authors.lastname: Liao
authors.affiliation: Institute of Biomedical Engineering, National Taiwan University, Taipei 106, Taiwan, ROC; Institute of Biomedical Electronic and Bioinformatics, National Taiwan University, Taipei 106, Taiwan, ROC; Center for Emerging Material and Advanced Devices, National Taiwan University, Taipei 106, Taiwan, ROC. Electronic address: cwlinx@ntu.edu.tw.
authors.forename: Chii-Wann
authors.initials: CW
authors.lastname: Lin
mesh_terms: D052157:Aptamers, Nucleotide / Q000737:chemistry; D015374:Biosensing Techniques; D003124:Colorimetry / Q000379:methods; D004247:DNA / Q000737:chemistry*; D004277:DNA, Single-Stranded / Q000737:chemistry; D006046:Gold / Q000737:chemistry; D053768:Metal Nanoparticles / Q000737:chemistry*; D021141:Nucleic Acid Amplification Techniques / Q000379:methods; D011506:Proteins / Q000737:chemistry / Q000302:isolation & purification*
chemical_list: D052157:Aptamers, Nucleotide; D004277:DNA, Single-Stranded; D011506:Proteins; D006046:Gold; D004247:DNA
keywords: Aptamer; Branched DNA cascade amplification; Colorimetric detection; Gold Nanoparticle; Vascular endothelial growth factor