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.

Lateral flow (immuno)assay: its strengths, weaknesses, opportunities and threats. A literature survey

“…The use of other coloured nanoparticles was mentioned as well. Among those are carbon [2,23] and selenium [22]. Chemiluminescent and fluorescent nanoparticles are used less often [9,16,58,79].…”

“…Labels are made of coloured or fluorescent nanoparticles with sizes of 15-800 nm, allowing an unobstructed flow through the membrane. They are often made of colloidal gold [1,[17][18][19][20] or latex [21], less often selenium [22], carbon [2,23] or liposomes [24][25][26][27][28][29] are used. Latex nanoparticles are coloured [21] for optical detection.…”

“…Applications are often designed where an on/off signal is sufficient. The best-known application is the pregnancy test [1,2]. Results usually come within 10-20 min.…”

Development of an immunochromatographic assay based on carbon nanoparticles for the determination of the phytoregulator forchlorfenuron

“…The carbon black-on-white signal allows for sensitivities down to the low picomolar range. Other advantages attributed to carbon nanoparticles are the very low cost of the starting material, the ease of preparation, and the stability of the conjugates (PosthumaTrumpie et al, 2012; van Amerongen et al, 1993).…”

Pesticides in Food - Immunochromatographic Detection of Thiabendazole and Methiocarb

“…On the membrane two lines are applied: control line (C-line) with immobilised rabbit anti-swine antibody (RASw) and the test line (T-line) with the conjugate ovalbumine-thiabendazole (OVA-TBZ) or ovalbumine-methiocarb (OVA-MET), respectively. Instead of colloidal gold detection colloidal carbon was used (Van Amerongen et al 1993), which was conjugated with the swine anti-mouse antibody (SwAM; antibody against specific anti-pesticide monoclonal antibody). The pesticide from the sample competed with the immobilised pesticide for the limited number of binding sites on the antibody molecule, which was in this work the specific monoclonal antibody against the given pesticide.…”