title: A simple method for preparing spectrally encoded magnetic beads for multiplexed detection.
abstract: This report describes a simple method for preparing encoded microspheres for use in multiplexed biological detection. In this method, hydrophobic trioctylphosphine oxide (TOPO)-capped CdSe@ZnS quantum dots (QDs) are assembled on polyamine-coated microspheres in chloroform and encapsulated in an outer shell of silica nanoparticles functionalized with a specific recognition surface. Because TOPO-capped QDs are assembled instead of their water-soluble equivalents, the microspheres are highly luminescent. The amount of QDs assembled depends only on the surface area of the substrate, and therefore, the photoluminescence intensity increased uniformly in proportion to the number of QD layers assembled. The outer shell of silica nanoparticles confers stability on the assembled QDs but has no effect on their photoluminescence because it is transparent to excitatory and emitted light. It was activated with aminosilane and functionalized with a recognition surface of protein antigens using disulfide exchange chemistry. Magnetic beads furnished with spectral codes of up to three colors of QDs matched to specific recognition surfaces were used as multianalyte sensors for serum proteins.
authors.affiliation: Department of Chemistry, Liverpool University, Liverpool L69 7ZD, UK. R.Wilson@liv.ac.uk
authors.forename: Robert
authors.initials: R
authors.lastname: Wilson
authors.forename: David G
authors.initials: DG
authors.lastname: Spiller
authors.forename: Ian A
authors.initials: IA
authors.lastname: Prior
authors.forename: Kees J
authors.initials: KJ
authors.lastname: Veltkamp
authors.forename: Alistair
authors.initials: A
authors.lastname: Hutchinson
mesh_terms: D000818:Animals; D000941:Antigens / Q000737:chemistry / Q000378:metabolism; D002417:Cattle; D002623:Chemistry Techniques, Analytical / Q000295:instrumentation*; D003116:Color; D006801:Humans; D008280:Magnetics; D008863:Microspheres; D053758:Nanoparticles / Q000737:chemistry; D009943:Organophosphorus Compounds / Q000737:chemistry; D011073:Polyamines / Q000737:chemistry; D045663:Quantum Dots; D012822:Silicon Dioxide / Q000737:chemistry; D012997:Solvents / Q000737:chemistry; D013499:Surface Properties
chemical_list: D000941:Antigens; D009943:Organophosphorus Compounds; D011073:Polyamines; D012997:Solvents; D012822:Silicon Dioxide; C044965:trioctyl phosphine oxide