title: Direct surface-enhanced Raman scattering analysis of DNA duplexes.
abstract: The exploration of the genetic information carried by DNA has become a major scientific challenge. Routine DNA analysis, such as PCR, still suffers from important intrinsic limitations. Surface-enhanced Raman spectroscopy (SERS) has emerged as an outstanding opportunity for the development of DNA analysis, but its application to duplexes (dsDNA) has been largely hampered by reproducibility and/or sensitivity issues. A simple strategy is presented to perform ultrasensitive direct label-free analysis of unmodified dsDNA with the means of SERS by using positively charged silver colloids. Electrostatic adhesion of DNA promotes nanoparticle aggregation into stable clusters yielding intense and reproducible SERS spectra at nanogram level. As potential applications, we report the quantitative recognition of hybridization events as well as the first examples of SERS recognition of single base mismatches and base methylations (5-methylated cytosine and N6-methylated Adenine) in duplexes.
authors.affiliation: Departamento de Química Fisica e Inorganica, Universitat Rovira i Virgili and Centro de Tecnologia Química, Carrer de Marcel lí Domingo s/n, 43007 Tarragona (Spain); Medcom Advance SA, Viladecans Bussines Park, Edificio Brasil, C/Bertran i Musitu, 83-85, 08840 Viladecans (Barcelona) (Spain). luca.guerrini@ctqc.org.
authors.forename: Luca
authors.initials: L
authors.lastname: Guerrini
authors.forename: Željka
authors.initials: Ž
authors.lastname: Krpetić
authors.forename: Danny
authors.initials: D
authors.lastname: van Lierop
authors.forename: Ramon A
authors.initials: RA
authors.lastname: Alvarez-Puebla
authors.forename: Duncan
authors.initials: D
authors.lastname: Graham
mesh_terms: D044503:5-Methylcytosine / Q000737:chemistry; D020137:Base Pair Mismatch; D004247:DNA / Q000032:analysis*; D053758:Nanoparticles / Q000737:chemistry; D009693:Nucleic Acid Hybridization; D013059:Spectrum Analysis, Raman; D055672:Static Electricity
chemical_list: D044503:5-Methylcytosine; D004247:DNA
keywords: DNA; hybridization; methylated bases; single-base mismatch; surface-enhanced Raman spectroscopy