Recognition of hypermethylated triplet repeats in vitro by cationic nanoparticles

L. Gearheart, K. K. Caswell, C. J. Murphy

Research output: Contribution to journalArticlepeer-review


Genomic DNA contains many higher-order structural deviations from the Watson-Crick global average. The massive expansion and hypermethylation of the duplex triplet repeat (CCG)n(CCG)n has characteristic higher-order structures that are associated with the fragile X syndrome. We have used luminescent mineral nanoparticles of protein-sized cadmium sulfide in optical assays to detect anomalous DNA structures. The photoluminescence of these particle is sensitive to the presence and nature of adsorbates. We previously found that our nanoparticles bind the fragile X repeat well but do not bind to normal double-helical DNA. In this study, we have determined that these particles are also able to detect the hypermethylated forms of these triplet repeats. Therefore, these nanoparticles may form the basis for future optical assays of higher-order DNA structures, especially those associated with human disease.

Original languageEnglish (US)
Pages (from-to)111-115
Number of pages5
JournalJournal of biomedical optics
Issue number2
StatePublished - Apr 2001
Externally publishedYes


  • CdS
  • DNA
  • Nanoparticle
  • Oligonucleotide
  • Photoluminescence
  • Quantum dot

ASJC Scopus subject areas

  • Clinical Biochemistry
  • Radiology Nuclear Medicine and imaging
  • Atomic and Molecular Physics, and Optics
  • Radiological and Ultrasound Technology


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