title: Colorimetric detection of DNA sequences based on electrostatic interactions with unmodified gold nanoparticles.
abstract: We find that single- and double-stranded oligonucleotides have different propensities to adsorb on gold nanoparticles in colloidal solution. We use this observation to design a hybridization assay based on color changes associated with gold aggregation. Because the underlying adsorption mechanism is electrostatic, no covalent functionalization of the gold, the probe, or the target DNA is required. Hybridization conditions can be optimized because it is completely separated from the detection step. The assay is complete within 5 min, and <100 femtomoles of target produces color changes observable without instrumentation. Single-base-pair mismatches are easily detected.
authors.affiliation: Department of Chemistry, University of Rochester, Rochester, NY 14627, USA.
authors.forename: Huixiang
authors.initials: H
authors.lastname: Li
authors.forename: Lewis
authors.initials: L
authors.lastname: Rothberg
mesh_terms: D000327:Adsorption; D020137:Base Pair Mismatch; D001483:Base Sequence; D015374:Biosensing Techniques / Q000379:methods; D003124:Colorimetry / Q000379:methods*; D004247:DNA / Q000032:analysis* / Q000235:genetics; D017979:Gold Colloid / Q000737:chemistry*; D036103:Nanotechnology / Q000379:methods; D009690:Nucleic Acid Conformation; D009693:Nucleic Acid Hybridization / Q000235:genetics / Q000379:methods; D015345:Oligonucleotide Probes / Q000737:chemistry; D010316:Particle Size; D017422:Sequence Analysis, DNA / Q000379:methods*; D013050:Spectrometry, Fluorescence; D013059:Spectrum Analysis, Raman; D055672:Static Electricity
chemical_list: D017979:Gold Colloid; D015345:Oligonucleotide Probes; D004247:DNA