Document Detail

Colorimetric and ultrasensitive bioassay based on a dual-amplification system using aptamer and DNAzyme.
MedLine Citation:
PMID:  22533853     Owner:  NLM     Status:  MEDLINE    
Rapid detection of ultralow amount of biomarkers in a biologically complex mixture remains a major challenge. Herein, we report a novel aptamer-based protein detection assay that integrates two signal amplification processes, namely, polymerase-mediated rolling-circle amplification (RCA) and DNA enzyme-catalyzed colorimetric reaction. The target biomarker is captured in a sandwich assay by primary aptamer-functionalized microbeads (MBs) and a secondary aptamer that is connected to a RCA primer/circular template complex. RCA reaction, which amplifies the single biomarker binding events by a factor of hundreds to thousands (the first amplification) produces a long DNA molecule containing multiple DNAzyme units. The peroxidase-like DNAzyme catalyzes the oxidation of 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (the second amplification), which generates a blue-green colorimetric signal. This new biosensing platform permits the ultrasensitive, label-free, colorimetric detection of biomarker in real time. Using platelet-derived growth factor B-chain (PDGF-BB) as a model system, we demonstrated that our assay can detect a protein marker specifically in a serum-containing medium, at a concentration as low as 0.2 pg/mL in ∼2 h, which rivals traditional assays such as ELISA. We anticipate this simple methodology for biomarker detection can find utility in point-of-care applications.
Longhua Tang; Yang Liu; Md Monsur Ali; Dong Ku Kang; Weian Zhao; Jinghong Li
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2012-05-11
Journal Detail:
Title:  Analytical chemistry     Volume:  84     ISSN:  1520-6882     ISO Abbreviation:  Anal. Chem.     Publication Date:  2012 Jun 
Date Detail:
Created Date:  2012-07-03     Completed Date:  2012-10-23     Revised Date:  2013-09-17    
Medline Journal Info:
Nlm Unique ID:  0370536     Medline TA:  Anal Chem     Country:  United States    
Other Details:
Languages:  eng     Pagination:  4711-7     Citation Subset:  IM    
Department of Chemistry, Beijing Key Laboratory for Analytical Methods and Instrumentation, Tsinghua University, Beijing, China 100084.
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MeSH Terms
Aptamers, Nucleotide / chemistry*
Biosensing Techniques / methods*
DNA Primers / chemistry
DNA, Catalytic / chemistry*
DNA, Circular / chemistry
Hydrogen Peroxide
Proto-Oncogene Proteins c-sis / blood*
Recombinant Proteins / blood
Serum Albumin, Bovine
Sulfonic Acids
Reg. No./Substance:
0/Aptamers, Nucleotide; 0/DNA Primers; 0/DNA, Catalytic; 0/DNA, Circular; 0/Proto-Oncogene Proteins c-sis; 0/Recombinant Proteins; 0/Serum Albumin, Bovine; 0/Sulfonic Acids; 0/Thiazoles; 0/platelet-derived growth factor BB; 1405-69-2/Avidin; 28752-68-3/2,2'-azino-di-(3-ethylbenzothiazoline)-6-sulfonic acid; 58-85-5/Biotin; 7722-84-1/Hydrogen Peroxide

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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