title: Covalent attachment of functionalized cardiolipin on a biosensor gold surface allows repetitive measurements of anticardiolipin antibodies in serum.
abstract: Antiphospholipid antibodies (aPL) are a relevant serological indicator of antiphospholipid syndrome (APS). A solid-state surface with covalently bound ω-amine-functionalized cardiolipin was established and the binding of β2-glycoprotein I (β2-GPI) was investigated either by use of surface plasmon resonance (SPR) biosensor, by electrically switchable DNA interfaces (switchSENSE) and by scanning tunneling microscopy (STM). STM could clearly visualize the attachment of β2-GPI to the cardiolipin surface. Using the switchSENSE sensor, β2-GPI as specific ligand could be identified by increased hydrodynamic friction. The binding of anti-cardiolipin antibodies (aCL) was detected against the ω-amine-functionalized cardiolipin-modified SPR biosensor (aCL biosensor) using sera from healthy donors, APS patients and syphilis patients. Our results showed that the aCL biosensor is a much more sensitive diagnostic device for APS patients compared to previous methods. The specificity between β2-GPI-dependent autoimmune- and β2-GPI-independent infection-associated types of aPLs was also studied and they can be distinguished by the different binding kinetics and patterns.
authors.affiliation: Institut für Klinische Chemie und Pathobiochemie, Klinikum rechts der Isar der Technischen Universität München, Ismaninger Strasse 22, 81675 Munich, Germany. schlichtiger@klinchem.med.tu-muenchen.de
authors.forename: Alice
authors.initials: A
authors.lastname: Schlichtiger
authors.forename: Claudia
authors.initials: C
authors.lastname: Baier
authors.forename: Meng-Xin
authors.initials: MX
authors.lastname: Yin
authors.forename: Andrew B
authors.initials: AB
authors.lastname: Holmes
authors.forename: Makiko
authors.initials: M
authors.lastname: Maruyama
authors.forename: Ralf
authors.initials: R
authors.lastname: Strasser
authors.forename: Ulrich
authors.initials: U
authors.lastname: Rant
authors.forename: Markus
authors.initials: M
authors.lastname: Thaler
authors.forename: Peter B
authors.initials: PB
authors.lastname: Luppa
mesh_terms: D017153:Antibodies, Anticardiolipin / Q000737:chemistry / Q000276:immunology*; D016736:Antiphospholipid Syndrome / Q000097:blood / Q000276:immunology; D015374:Biosensing Techniques; D002308:Cardiolipins / Q000737:chemistry*; D004247:DNA / Q000032:analysis; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D006046:Gold / Q000737:chemistry*; D006801:Humans; D007700:Kinetics; D008024:Ligands; D016252:Microscopy, Scanning Tunneling / Q000379:methods; D008956:Models, Chemical; D008968:Molecular Conformation; D020349:Surface Plasmon Resonance / Q000379:methods; D013499:Surface Properties; D013997:Time Factors; D053482:beta 2-Glycoprotein I / Q000737:chemistry
chemical_list: D017153:Antibodies, Anticardiolipin; D002308:Cardiolipins; D008024:Ligands; D053482:beta 2-Glycoprotein I; D006046:Gold; D004247:DNA