title: Bead-based DNA diagnostic assay for chlamydia using nanoparticle-mediated surface-enhanced resonance Raman scattering detection within a lab-on-a-chip format.
abstract: There is a continued interest in the development of new on-chip protocols for the determination of the causes of infectious disease. In this paper, we demonstrate the use of surface-enhanced resonance Raman scattering (SERRS) for detecting the clinically relevant nucleic acid sequences of Chlamydia trachomatis in a bead-based lab-on-a-chip format, incorporating a solid-phase sample clean-up on-chip. The assay uses streptavidinated polymer microspheres to capture a biotinylated PCR product of the oligonucleotide sequence, which was subsequently hybridized against a complementary rhodamine-labeled, Raman active probe. Central to the assay is an in-channel integrated microfilter, which was used to retain the microspheres, enabling the bound target to be separated from the rest of the sample as part of a solid-phase clean-up (thereby removing any contributions from the background). After washing, the bound Rhodamine labeled detection probe was released thermally from the microspheres by heating and was subsequently mixed on-chip with a stream of silver nanoparticles. The signal was detected downstream using a Raman spectrometer to collect the SERRS response. The assay offers several advantages over traditional laboratory methods, including: the speed of the assay on-chip, the potential for sample clean-up; and the low volume of sample required.
authors.affiliation: Department of Electronics and Electrical Engineering, University of Glasgow, Oakfield Avenue, Glasgow, UK.
authors.forename: Paul B
authors.initials: PB
authors.lastname: Monaghan
authors.forename: Karen M
authors.initials: KM
authors.lastname: McCarney
authors.forename: Alastair
authors.initials: A
authors.lastname: Ricketts
authors.forename: Rachael E
authors.initials: RE
authors.lastname: Littleford
authors.forename: Frances
authors.initials: F
authors.lastname: Docherty
authors.forename: W Ewen
authors.initials: WE
authors.lastname: Smith
authors.forename: Duncan
authors.initials: D
authors.lastname: Graham
authors.forename: Jonathan M
authors.initials: JM
authors.lastname: Cooper
mesh_terms: D001483:Base Sequence; D002692:Chlamydia trachomatis / Q000737:chemistry*; D004247:DNA / Q000032:analysis*; D004867:Equipment Design; D053758:Nanoparticles / Q000737:chemistry*; D020411:Oligonucleotide Array Sequence Analysis / Q000379:methods*; D016133:Polymerase Chain Reaction / Q000379:methods; D012680:Sensitivity and Specificity; D012834:Silver / Q000737:chemistry; D013059:Spectrum Analysis, Raman / Q000379:methods*; D019809:Streptavidin / Q000737:chemistry*; D013499:Surface Properties
chemical_list: D012834:Silver; D004247:DNA; D019809:Streptavidin