Particle immunoassay

Harma, H., Tarkkinen, P., Soukka, T., and Lovgren, T. (2000) Miniature single-particle immunoassay for prostate-specific antigen in serum using recombinant Fab fragments. Clin. Chem. 46, 1755-1761. 

Xu T, Cho IK, Wang D, Rubio FM, Shelver WL, Gasc AME, Li J, Li QX (2009) Suitability of magnetic particle immunoassay for the analysis of PBDEs in Hawaiian euryhaline fish and crabs in comparison with gas chromatography/electron capture detection-ion trap mass spectrometry. Environmental Pollution 157 417 22... 

Hayes, M.C., S.W. Jourdan, and D.P. Herzog (1996). Determination of atrazine in water by magnetic particle immunoassay Collaborative study. J. Assoc. Off. Anal. Chem. Int., 79 529-537. 

Forerunners of nonisotopic immunoassay had already appeared before radioimmunoassay was developed. For example, nephelometry is based on precipitation, which is known as the classical immune reaction, and the ideas of particle immunoassay and viroimmunoassay seem to have developed from the hemagglutination test. The principles of enzyme and fluorescence immunoassay had already been used as enzyme and fluorescence antibody techniques in histochemical analysis. In 1971, two groups reported use of an enzyme immunoassay (E5, V2). Leute et al. reported spin immunoassay, which has spurred recent development of nonisotopic immunoassays (L5). 

Sol particle immunoassay was developed by Leuvering et al. of the Organon group (L6). They used inorganic (metal) colloidal particles as a label... 

The first immunoassay performed in a capillary driven system was reported in 1978 [67]. Based on this technique, the commonly known over-the-counter pregnancy test was introduced into the market in the middle of the 80 s. Today, this microfluidic platform is commonly designated as a lateral flow test (LAT) [14]. Other terms are test strip , immunochromatographic strip , immunocapillary tests or sol particle immunoassay (SPIA) [68]. Astonishingly, hardly any publications from a microfluidic point of view or in terns of material classification exist, and apparently many company secrets are kept unpublished [69]. 

Figure 20 shows a calibration curve for a sufficiently rapid and technically simple quantitative sol-particle immunoassay (SPIA [18]). The assay is based on biospecific aggregation of 15-nm gold conjugates to Protein A due to interaction with hIgG molecules. We have found a direct correlation between the amount of the second added protein initiating aggregation and the spectral position of the extinction maximum. 

Fiore, M., Mitchell, J, Doan, T, Nelson, R., Winter, G., Grandone, C., Zeng, K., Haraden, R., Smith, J., Harris, K, Leszczynski, J., Berry, D., Safford, S., Barnes, G., Scholnick, A., and Ludington, K. (1988) The Abbott IMx automated benchtop inununochemistry analyzer system. Clin. Chem. 34,1726-1732. 4 Yost, D., Russell, J., and Yang, H (1990) Non-Metal Colloidal Particle Immunoassay United States Patent 4,954,452. 

Enzyme immunoassays, in a card-test format, are also used for screening carcasses by testing of urine for specific antimicrobial residues such as sulfadimidine and chloramphenicol. The sol particle immunoassay uses adsorption of specific antibodies to dyed colloidal particles (e.g., carbon) as a mechanism for making directly visible the presence of residues (i.e., antigen) in the sample. A lateral flow membrane device is used to identify residue-positive samples through the absence of color formation at the test capture zone (Figure 5). 

Magnetic particle immunoassay Another variant of the solid-phase immunoassay format depends on coupling antibodies to magnetic particles. The assay... 

Sol-particle immunoassay (SPIA) Metal atoms (i) Visible response (ii) Colorimetry Simple labelling (30)... 

Other methods with potential application in sensor development include certain enzyme immunoassays and sol-particle immunoassay. The enzyme methods that are potentially useful are those where the detection of the enzyme is carried out with a substrate that produces colour that may be determined colorimetrically, or a substrate that produces fluorescence. 

The method of sol-particle immunoassay uses colloidal metal particles as the label. Typically these labels have been colloidal gold and colloidal silver. Detection in this type of assay is carried out visually, colorimetrically or by atomic absorption spectroscopy with electrothermal atomization. The colorimetric methods obviously offer potential in sensor development and the detection limits in the pmol 1 range are useful. 

Diagnostic sol particle immunoassay microscopy labelling reagents Chemical and biosensing Nanoscale electronics Homogeneous catalysis High-order nonlinear optical susceptibility... 

J. H. W. Leuvering, B. C. Goverde, P. Thai and A. Schuurs. A Homogeneous Sol Particle Immunoassay for Human Chorionic- Gonadotropin Using Monoclonal-Antibodies. Journal of Immunological Methods 60 (1-2), 9-23 (1983). 

---