title: Colloidal carbon particles as a new label for rapid immunochemical test methods: quantitative computer image analysis of results.
abstract: Colloidal carbon particles can serve as label in sol particle immunoassays. The universal applicability of these particles in qualitative and (semi)quantitative immunoassays has been demonstrated. Sol particle and/or dipstick immunoassays, not yet optimized in terms of sensitivity, are discussed. The colloidal label has been used successfully in a mouse immunoglobulin isotyping kit. Human serum albumin spotted onto nitrocellulose in a concentration range of 7.8 to 1000 ng could be detected using anti-albumin antibody absorbed onto colloidal carbon particles. It was also possible to perform a competitive assay with this conjugate for a concentration range of free human serum albumin varying from 0.25 to 6.75 micrograms. The Kunitz-type trypsin inhibitor from soybean was determined by a colloidal carbon based immunoassay in a range of 2.5 to 160 ng. In this assay, free and colloidal carbon-bound inhibitor competed for binding specific antibodies spotted onto a nitrocellulose membrane. An image- and data-processing procedure has been developed that enables a rapid and simple quantification of colloidal carbon sol particle immunoassays. The average grey level of a spot is taken as a measure for quantitative purposes. This so-called Sol-particle Image Processed ImmunoAssay (SIPIA) procedure is equally well applicable to assays using other colloidal particles.
authors.affiliation: Agrotechnological Research Institute ATO-DLO, Wageningen, The Netherlands.
authors.forename: A
authors.initials: A
authors.lastname: van Amerongen
authors.forename: J H
authors.initials: JH
authors.lastname: Wichers
authors.forename: L B
authors.initials: LB
authors.lastname: Berendsen
authors.forename: A J
authors.initials: AJ
authors.lastname: Timmermans
authors.forename: G D
authors.initials: GD
authors.lastname: Keizer
authors.forename: A W
authors.initials: AW
authors.lastname: van Doorn
authors.forename: A
authors.initials: A
authors.lastname: Bantjes
authors.forename: W M
authors.initials: WM
authors.lastname: van Gelder
mesh_terms: D000818:Animals; D007611:Aprotinin / Q000032:analysis; D002244:Carbon; D003102:Colloids; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007118:Immunoassay / Q000379:methods*; D007132:Immunoglobulin Isotypes / Q000032:analysis; D051379:Mice; D051381:Rats; D012709:Serum Albumin / Q000032:analysis
chemical_list: D003102:Colloids; D007132:Immunoglobulin Isotypes; D012709:Serum Albumin; D002244:Carbon; D007611:Aprotinin