Amplified single base-pair mismatch detection via aggregation of exonuclease-sheared gold nanoparticles

Anal Chem. 2014 Apr 1;86(7):3461-7. doi: 10.1021/ac4040373. Epub 2014 Mar 19.


Single nucleotide polymorphism (SNP) detection is important for early diagnosis, clinical prognostics, and disease prevention, and a rapid and sensitive low-cost SNP detection assay would be valuable for resource-limited clinical settings. We present a simple platform that enables sensitive, naked-eye detection of SNPs with minimal reagent and equipment requirements at room temperature within 15 min. SNP detection is performed in a single tube with one set of DNA probe-modified gold nanoparticles (AuNPs), a single exonuclease (Exo III), and the target in question. Exo III's apurinic endonucleolytic activity differentially processes hybrid duplexes between the AuNP-bound probe and DNA targets that are perfectly matched or contain a single-base mismatch. For perfectly matched targets, Exo III's exonuclease activity facilitates a process of target recycling that rapidly shears DNA probes from the particles, generating an AuNP aggregation-induced color change, whereas no such change occurs for mismatched targets. This color change is easily observed with as little as 2 nM of target, 100-fold lower than the target concentration required for reliable naked eye observation with unmodified AuNPs in well-optimized reaction conditions. We further demonstrate that this system can effectively discriminate a range of different mismatches.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Base Pair Mismatch*
  • Exonucleases / chemistry*
  • Gold / chemistry*
  • Metal Nanoparticles*
  • Polymorphism, Single Nucleotide
  • Spectrophotometry, Ultraviolet


  • Gold
  • Exonucleases