title: Selective colorimetric detection of polynucleotides based on the distance-dependent optical properties of gold nanoparticles.
abstract: A highly selective, colorimetric polynucleotide detection method based on mercaptoalkyloligonucleotide-modified gold nanoparticle probes is reported. Introduction of a single-stranded target oligonucleotide (30 bases) into a solution containing the appropriate probes resulted in the formation of a polymeric network of nanoparticles with a concomitant red-to-pinkish/purple color change. Hybridization was facilitated by freezing and thawing of the solutions, and the denaturation of these hybrid materials showed transition temperatures over a narrow range that allowed differentiation of a variety of imperfect targets. Transfer of the hybridization mixture to a reverse-phase silica plate resulted in a blue color upon drying that could be detected visually. The unoptimized system can detect about 10 femtomoles of an oligonucleotide.
authors.affiliation: Department of Chemistry, Northwestern University, Evanston, IL 60208, USA.
authors.forename: R
authors.initials: R
authors.lastname: Elghanian
authors.forename: J J
authors.initials: JJ
authors.lastname: Storhoff
authors.forename: R C
authors.initials: RC
authors.lastname: Mucic
authors.forename: R L
authors.initials: RL
authors.lastname: Letsinger
authors.forename: C A
authors.initials: CA
authors.lastname: Mirkin
mesh_terms: D015374:Biosensing Techniques; D003124:Colorimetry; D006046:Gold; D008832:Microchemistry; D009693:Nucleic Acid Hybridization; D015345:Oligonucleotide Probes; D011089:Polydeoxyribonucleotides / Q000032:analysis*; D013053:Spectrophotometry; D013696:Temperature
chemical_list: D015345:Oligonucleotide Probes; D011089:Polydeoxyribonucleotides; D006046:Gold