Label-free detection of nanomolar unmodified single- and double-stranded dna by using surface-enhanced raman spectroscopy on Ag and Au colloids

Evanthia Papadopoulou, Steven E. J. Bell

Research output: Contribution to journalArticlepeer-review

51 Citations (Scopus)

Abstract

Unlabelled single- and double-stranded DNA (ssDNA and dsDNA, respectively) has been detected at concentrations =10-9?M by surface-enhanced Raman spectroscopy. Under appropriate conditions the sequences spontaneously adsorbed to the surface of both Ag and Au colloids through their nucleobases; this allowed highly reproducible spectra with good signal-to-noise ratios to be recorded on completely unmodified samples. This eliminated the need to promote absorption by introducing external linkers, such as thiols. The spectra of model ssDNA sequences contained bands of all the bases present and showed systematic changes when the overall base composition was altered. Initial tests also showed that small but reproducible changes could be detected between oligonucleotides with the same bases arranged in a different order. The spectra of five ssDNA sequences that correspond to different strains of the Escherichia coli bacterium were found to be sufficiently composition-dependent so that they could be differentiated without the need for any advanced multivariate data analysis techniques.
Original languageEnglish
Pages (from-to)5394-5400
Number of pages7
JournalChemistry-a European Journal
Volume18
Issue number17
Early online date20 Mar 2012
DOIs
Publication statusPublished - 23 Apr 2012

ASJC Scopus subject areas

  • Chemistry(all)

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