Nanometer-scale mapping and single-molecule detection with color-coded nanoparticle probes

Amit Agrawal, Rajesh Deo, Geoffrey D. Wang, May D. Wang, Shuming Nie

Research output: Contribution to journalArticlepeer-review


We report a method for single-molecule detection and biomolecular structural mapping based on dual-color imaging and automated colocalization of bioconjugated nanoparticle probes at nanometer precision. In comparison with organic dyes and fluorescent proteins, nanoparticle probes such as fluorescence energy-transfer nanobeads and quantum dots provide significant advantages in signal brightness, photostability, and multicolor-light emission. As a result, we have achieved routine two-color super-resolution imaging and single-molecule detection with standard fluorescence microscopes and inexpensive digital color cameras. By using green and red nanoparticles to simultaneously recognize two binding sites on a single target, individual biomolecules such as nucleic acids are detected and identified without target amplification or probe/target separation. We also demonstrate that a powerful astrophysical method (originally developed to analyze crowded stellar fields) can be used for automated and rapid statistical analysis of nanoparticle colocalization signals. The ability to rapidly localize bright nanoparticle probes at nanometer precision has implications not only for ultrasensitive medical detection but also for structural mapping of molecular complexes in which individual components are tagged with color-coded nanoparticles.

Original languageEnglish (US)
Pages (from-to)3298-3303
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number9
StatePublished - Mar 4 2008
Externally publishedYes


  • Colocalization
  • Multicolor
  • Superresolution

ASJC Scopus subject areas

  • General


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