title: Organically modified silica nanoparticles doped with new acridine-1,2-dioxetane analogues as thermochemiluminescence reagentless labels for ultrasensitive immunoassays.
abstract: Doped organically modified silica nanoparticles (ORMOSIL NPs) with luminescent molecules represent a potent approach to signal amplification in biomolecule labeling. Herein, we report the synthesis of new ORMOSIL NPs incorporating thermochemiluminescent (TCL) 1,2-dioxetane derivatives to prepare TCL labels for ultrasensitive immunoassay, displaying a detectability comparable to those offered by other conventional luminescence-based systems. Amino-functionalized ORMOSIL NPs were synthesized for inclusion of acridine-containing 1,2-dioxetane derivatives with a fluorescence energy acceptor. The doped ORMOSIL NPs were further functionalized with biotin for binding to streptavidin-labeled species to be used as universal detection reagents for immunoassays. A quantitative non-competitive immunoassay for streptavidin has been developed by immobilizing anti-streptavidin antibody to capture streptavidin, then the antibody-bound streptavidin was detected by the biotinylated TCL ORMOSIL NPs. The analytical performance was similar to that obtained by chemiluminescent (CL) detection using horseradish peroxidase (HRP) as label, being the limits of detection 2.5-3.8 and 0.8 ng mL(-1) for TCL and CL detection, respectively. In addition, since the TCL emission is simply initiated by thermolysis of the label, chemical reagents were not required, thus allowing reagentless detection with a simplification of the analytical protocols. A compact mini dark box device based on the use of a cooled charge-coupled device (CCD) and a miniaturized heater has been developed and used to quantify the light emission after heat decomposition of the label at a temperature of 90-120 °C. These characteristics make TCL-doped ORMOSIL NPs ideal universal nanoprobes for ultrasensitive bioassays such as immuno- and DNA-based assay.
authors.affiliation: Advanced Applications in Mechanical Engineering and Materials Technology, Interdepartmental Center for Industrial Research, Alma Mater Studiorum, University of Bologna, Viale Risorgimento 2, 40136, Bologna, BO, Italy, massimo.difusco@unibo.it.
authors.forename: Massimo
authors.initials: M
authors.lastname: Di Fusco
authors.forename: Arianna
authors.initials: A
authors.lastname: Quintavalla
authors.forename: Marco
authors.initials: M
authors.lastname: Lombardo
authors.forename: Massimo
authors.initials: M
authors.lastname: Guardigli
authors.forename: Mara
authors.initials: M
authors.lastname: Mirasoli
authors.forename: Claudio
authors.initials: C
authors.lastname: Trombini
authors.forename: Aldo
authors.initials: A
authors.lastname: Roda
mesh_terms: D000166:Acridines / Q000737:chemistry*; D007118:Immunoassay / Q000379:methods*; D057230:Limit of Detection; D049449:Luminescence; D046529:Microscopy, Electron, Transmission; D053758:Nanoparticles; D012822:Silicon Dioxide / Q000737:chemistry*; D013696:Temperature
chemical_list: D000166:Acridines; D012822:Silicon Dioxide