title: Homogeneous detection of unamplified genomic DNA sequences based on colorimetric scatter of gold nanoparticle probes.
abstract: Nucleic acid diagnostics is dominated by fluorescence-based assays that use complex and expensive enzyme-based target or signal-amplification procedures. Many clinical diagnostic applications will require simpler, inexpensive assays that can be done in a screening mode. We have developed a 'spot-and-read' colorimetric detection method for identifying nucleic acid sequences based on the distance-dependent optical properties of gold nanoparticles. In this assay, nucleic acid targets are recognized by DNA-modified gold probes, which undergo a color change that is visually detectable when the solutions are spotted onto an illuminated glass waveguide. This scatter-based method enables detection of zeptomole quantities of nucleic acid targets without target or signal amplification when coupled to an improved hybridization method that facilitates probe-target binding in a homogeneous format. In comparison to a previously reported absorbance-based method, this method increases detection sensitivity by over four orders of magnitude. We have applied this method to the rapid detection of mecA in methicillin-resistant Staphylococcus aureus genomic DNA samples.
authors.affiliation: Department of Applied Science, Nanosphere, Inc., 4088 Commercial Avenue, Northbrook, Illinois 60062, USA. jstorfhoff@nanosphere.com
authors.forename: James J
authors.initials: JJ
authors.lastname: Storhoff
authors.forename: Adam D
authors.initials: AD
authors.lastname: Lucas
authors.forename: Viswanadham
authors.initials: V
authors.lastname: Garimella
authors.forename: Y Paul
authors.initials: YP
authors.lastname: Bao
authors.forename: Uwe R
authors.initials: UR
authors.lastname: Müller
mesh_terms: D001426:Bacterial Proteins / Q000032:analysis / Q000737:chemistry / Q000235:genetics; D003124:Colorimetry / Q000379:methods*; D004247:DNA / Q000032:analysis*; D015342:DNA Probes / Q000737:chemistry*; D023281:Genomics / Q000379:methods; D006046:Gold / Q000737:chemistry*; D008832:Microchemistry / Q000379:methods; D049329:Nanostructures / Q000737:chemistry; D046915:Penicillin-Binding Proteins; D017422:Sequence Analysis, DNA / Q000379:methods*; D013211:Staphylococcus aureus / Q000737:chemistry / Q000235:genetics
chemical_list: D001426:Bacterial Proteins; D015342:DNA Probes; D046915:Penicillin-Binding Proteins; C487789:mecA protein, Staphylococcus aureus; D006046:Gold; D004247:DNA