Proximity extension of circular DNA aptamers with real-time protein detection

Daniel A. Di Giusto, Wjatschesslaw A. Wlassoff, J. Justin Gooding, Barbara A. Messerle, Garry C. King*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

74 Citations (Scopus)
18 Downloads (Pure)


Multivalent circular aptamers or 'captamers' have recently been introduced through the merger of aptameric recognition functions with the basic principles of DNA nanotechnology. Aptamers have strong utility as protein-binding motifs for diagnostic applications, where their ease of discovery, thermal stability and low cost make them ideal components for incorporation into targeted protein assays. Here we report upon a property specific to circular DNA aptamers: Their intrinsic compatibility with a highly sensitive protein detection method termed the 'proximity extension' assay. The circular DNA architecture facilitates the integration of multiple functional elements into a single molecule: Aptameric target recognition, nucleic acid hybridization specificity and rolling circle amplification. Successful exploitation of these properties is demonstrated for the molecular analysis of thrombin, with the assay delivering a detection limit nearly three orders of magnitude below the dissociation constants of the two contributing aptamer-thrombin interactions. Real-time signal amplification and detection under isothermal conditions points towards potential clinical applications, with both fluorescent and bioelectronic methods of detection achieved. This application elaborates the pleiotropic properties of circular DNA aptamers beyond the stability, potency and multitargeting characteristics described earlier.

Original languageEnglish
Pages (from-to)1-7
Number of pages7
JournalNucleic Acids Research
Issue number6
Publication statusPublished - 2005
Externally publishedYes

Bibliographical note

Copyright 2005 the Author(s). First published in Nucleic Acids Research, Vol. 33, No. 6, e64. The original publication is available at doi:10.1093/nar/gni063, published by Oxford University Press. Version archived for private and non-commercial use with the permission of the author/s and according to publisher conditions. For further rights please contact the publisher.


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