title: High sensitivity carbon nanotube based electrochemiluminescence sensor array.
abstract: Ink jet printed carbon nanotube forest arrays capable of detecting picomolar concentrations of immunoglobulin G (IgG) using electrochemiluminescence (ECL) are described. Patterned arrays of vertically aligned single walled carbon nanotube (SWCNT) forests were printed on indium tin oxide (ITO) electrodes. Capture anti-IgG antibodies were then coupled through peptide bond formation to acidic functional groups on the vertical nanotubes. IgG immunoassays were performed using silica nano particles (Si NP) functionalized with the ECL luminophore [Ru(bpy)(2)PICH(2)](2+)], and IgG labelled G1.5 acid terminated PAMAM dendrimers. PAMAM is poly(amido amine), bpy is 2,2'-bipyridyl and PICH(2) is (2-(4-carboxyphenyl)imidazo[4,5-f][1,10]phenanthroline). The carboxyl terminal of [Ru(bpy)(2)PICH(2)](2+) (fluorescence lifetime ≈ 682±5 ns) dye was covalently coupled to amine groups on the 800 nm diameter silica spheres in order to produce significant ECL enhancement in the presence of sodium oxalate as co-reactant in PBS at pH 7.2). Significantly, this SWCNT-based sensor array shows a wide linear dynamic range for IgG coated spheres (10(6) to 10(12) spheres) corresponding to IgG concentrations between 20 pM and 300 nM. A detection limit of 1.1±0.1 pM IgG is obtained under optimal conditions.
authors.affiliation: Biomedical Diagnostic Institute, National Center for Sensor Research, School of Chemical Sciences, Dublin City University, Dublin 9, Ireland.
authors.forename: Anita
authors.initials: A
authors.lastname: Venkatanarayanan
authors.forename: Karl
authors.initials: K
authors.lastname: Crowley
authors.forename: Elena
authors.initials: E
authors.lastname: Lestini
authors.forename: Tia E
authors.initials: TE
authors.lastname: Keyes
authors.forename: James F
authors.initials: JF
authors.lastname: Rusling
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Forster
mesh_terms: D015374:Biosensing Techniques / Q000295:instrumentation*; D003217:Conductometry / Q000295:instrumentation*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D006801:Humans; D007118:Immunoassay / Q000295:instrumentation*; D007074:Immunoglobulin G / Q000097:blood*; D008163:Luminescent Measurements / Q000295:instrumentation*; D046228:Microarray Analysis / Q000295:instrumentation*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
chemical_list: D007074:Immunoglobulin G