title: Lanthanide-containing polymer microspheres by multiple-stage dispersion polymerization for highly multiplexed bioassays.
abstract: We describe the synthesis and characterization of metal-encoded polystyrene microspheres by multiple-stage dispersion polymerization with diameters on the order of 2 mum and a very narrow size distribution. Different lanthanides were loaded into these microspheres through the addition of a mixture of lanthanide salts (LnCl(3)) and excess acrylic acid (AA) or acetoacetylethyl methacrylate (AAEM) dissolved in ethanol to the reaction after about 10% conversion of styrene, that is, well after the particle nucleation stage was complete. Individual microspheres contain ca. 10(6)-10(8) chelated lanthanide ions, of either a single element or a mixture of elements. These microspheres were characterized one-by-one utilizing a novel mass cytometer with an inductively coupled plasma (ICP) ionization source and time-of-flight (TOF) mass spectrometry detection. Microspheres containing a range of different metals at different levels of concentration were synthesized to meet the requirements of binary encoding and enumeration encoding protocols. With four different metals at five levels of concentration, we could achieve a variability of 624, and the strategy we report should allow one to obtain much larger variability. To demonstrate the usefulness of element-encoded beads for highly multiplexed immunoassays, we carried out a proof-of-principle model bioassay involving conjugation of mouse IgG to the surface of La and Tm containing particles and its detection by an antimouse IgG bearing a metal-chelating polymer with Pr.
authors.affiliation: Department of Chemistry, University of Toronto, 80 St George Street Toronto ON M5S3H6, Canada.
authors.forename: Ahmed I
authors.initials: AI
authors.lastname: Abdelrahman
authors.forename: Sheng
authors.initials: S
authors.lastname: Dai
authors.forename: Stuart C
authors.initials: SC
authors.lastname: Thickett
authors.forename: Olga
authors.initials: O
authors.lastname: Ornatsky
authors.forename: Dmitry
authors.initials: D
authors.lastname: Bandura
authors.forename: Vladimir
authors.initials: V
authors.lastname: Baranov
authors.forename: Mitchell A
authors.initials: MA
authors.lastname: Winnik
mesh_terms: D000818:Animals; D002614:Chelating Agents / Q000737:chemistry*; D007118:Immunoassay; D007074:Immunoglobulin G / Q000737:chemistry; D028581:Lanthanoid Series Elements / Q000737:chemistry*; D051379:Mice; D008855:Microscopy, Electron, Scanning; D008863:Microspheres; D015394:Molecular Structure; D011137:Polystyrenes / Q000138:chemical synthesis*; D013499:Surface Properties
chemical_list: D002614:Chelating Agents; D007074:Immunoglobulin G; D028581:Lanthanoid Series Elements; D011137:Polystyrenes