title: Giant platinum clusters: 2-nm covalent metal cluster labels.
abstract: A new class of covalently linkable platinum cluster reagents with core diameters close to 2 nm has been prepared. The new label offers the performance advantages and versatility of the 1.4-nm Nanogold in a larger label which is more clearly visualized against electron-dense regions of a specimen. Large platinum clusters were prepared by the reduction of platinum(II) acetate in the presence of 1,10-phenanthroline ligands which had been synthetically modified to include solubilizing and reactive cross-linkable functional groups. These were then conjugated site-specifically to antibody IgG molecules and to Fab' fragments and visualized by scanning transmission electron microscopy. The resulting conjugates may be autometallographically enhanced and show sensitivity similar to that of Nanogold conjugates in immunoblotting experiments. In preliminary experiments, they have also exhibited labeling of tissue antigens and penetrate to access nuclear targets.
authors.affiliation: Nanoprobes, Inc., 25 E. Loop Road, Suite 113, Stony Brook, New York 11790, USA.
authors.forename: R D
authors.initials: RD
authors.lastname: Powell
authors.forename: C M
authors.initials: CM
authors.lastname: Halsey
authors.forename: W
authors.initials: W
authors.lastname: Liu
authors.forename: V N
authors.initials: VN
authors.lastname: Joshi
authors.forename: J F
authors.initials: JF
authors.lastname: Hainfeld
mesh_terms: D000345:Affinity Labels / Q000737:chemistry; D006367:HeLa Cells / Q000737:chemistry; D006801:Humans; D015151:Immunoblotting; D007128:Immunoglobulin Fragments / Q000276:immunology / Q000378:metabolism; D007074:Immunoglobulin G / Q000276:immunology / Q000378:metabolism; D007150:Immunohistochemistry / Q000379:methods; D017348:Microscopy, Electron, Scanning Transmission / Q000379:methods; D015335:Molecular Probes / Q000138:chemical synthesis; D009942:Organometallic Compounds / Q000138:chemical synthesis; D010984:Platinum / Q000737:chemistry* / Q000378:metabolism; D016622:Silver Staining
chemical_list: D000345:Affinity Labels; D007128:Immunoglobulin Fragments; D007074:Immunoglobulin G; D015335:Molecular Probes; D009942:Organometallic Compounds; D010984:Platinum