Immunoassays latex

Latex agglutination immunoassays are easily formatted into simple kits which can provide yes/no and semiquantitative estimates of antigen (or antibody) in a sample. The first such assay was developed in 1957 for rheumatoid factor (15) and assays are on the market for the deterrnination of many species of bacteria, fungi. Mycoplasma, parasites, ckettsia, and vimses, as well as for the deterrnination of autoimmune disease, hormones (qv), dmgs (see Pharmaceuticals), and blood proteins (16). Latex agglutination is also the basis of many home pregnancy tests. 

Proteins may be covalently attached to the latex particle by a reaction of the chloromethyl group with a-amino groups of lysine residues. We studied this process (17) using bovine serum albumin as a model protein - the reaction is of considerable interest because latex-bound antigens or antibodies may be used for highly sensitive immunoassays. The temperature dependence of the rate of protein attachment to the latex particle was unusually small - this rate increased only by 27% when the temperature was raised from 25°C to 35°C. This suggests that non-covalent protein adsorption on the polymer is rate determining. On the other hand. the rate of chloride release increases in this temperature interval by a factor of 17 and while the protein is bound to the latex particle by only 2 bonds at 25°C, 22 bonds are formed at 35°C. 

One of the simplest methods of attaching biomolecules to hydrophobic polymeric particles is the use of passive adsorption. Some of the earliest examples related to the use of particles in immunoassays include the use of non-covalently adsorbed antibody or antigen onto latex microspheres. Protein adsorption onto hydrophobic particles takes place through strong interactions... 

S. Kurosawa, E. Tawara, N. Kamo, F. Ohta, and T. Hosokawa, Latex piezoelectric immunoassay detection of agglutination of antibody-bearing latex using a piezoelectric quartz crystal. Chem. Pharm. Bull. 38,1117-1120 (1990). 

M. Muratsugu, S. Kurosawa, and N. Kamo, Detection of antistreptolysin O antibody application of an initial rate method of latex piezoelectric immunoassay. Anal. Chem. 64, 2483-2487 (1992). 

H.O. Ghourchian and N. Kamo, Improvement of latex piezoelectric immunoassay detection of rheumatoid factor. Talanta 41, 401-406 (1994). 

Latex acrylic polymers, 22 41-43 Latex agglutination immunoassays, 14 141 Latex-based paper coatings, 1<8 124-125 Latex manufacturing equipment, 14 720, 721... 

A4. Abe, A., Yoshimura, Y., Sekine, T., Maeda, S., Yamashita, S., and Noma, A., Fully mechanized latex immunoassay for serum lipoprotein(a). Clin. Chim. Acta 225, 105-113 (1994). 

Penicillium/ Aspergillus Molds Latex Aglutination Immunoassay Holland Biotechnology Sanofi Diagnostics 101... 

Medina, M.B. 2004. Development of a fluorescent latex immunoassay for detection of a spectinomycin antibiotic. J. Agric. Food Chem. 52 3231-3236. 

S10. Sawai, M., Sudo, T., Okumura, H., Morita, S., Sato, S., Matsumoto, S., and Migita, S., A new photometric immunoassay of latex agglutination reaction with near infrared tur-... 

Uchida K, Gotoh A (2002) Measurement of cystatin-C and creatinine in urine. Clinica Chimica Acta 323 121-128 Umbreit A, Wiedemann G (2000) Determination of urinary protein fractions. A comparison with different electrophoretic methods and quantitatively determined protein concentrations. Clin Chim Acta 297 163-172 Viau C, Bernard A, Lauwerys R (1986) Determination of rat P2-microglobulin in urine and serum. I. Development of an immunoassay based on latex particles agglutination. J Appl Toxicol 6 185-189... 

Kato, N., and Caruso, F. (2005). Homogeneous, competitive fluorescence quenching immunoassay based on gold nanoparticle/polyelectrolyte coated latex particles. J. Phys. Chem. B 109 19604-19612. 

Clostridium difficile can be cultured from the stool, and toxins A and B can be assessed by different techniques (116). The most accurate method is still a cytotoxin tissue culture assay. This detects the cytopathic effect of cytotoxin B, which can be neutralized by Clostridium sordellii antitoxin, but it takes 24 8 hours to show a result. Alternative tests that produce faster results have been developed. A latex agglutination test lacks sensitivity and specificity, and does not distinguish toxigenic from non-toxigenic strains. An enzyme immunoassay for toxin A may be an acceptable alternative to the cell cytotoxin assay and the results are rapidly available. A dot immunobinding assay has not yet been extensively studied (164). 

While no real labels meet all of these needs, the properties of some of the more recently introduced labelling systems are approaching the ideal. Radioisotopes, once the only type of label used for immunoassays, have clearly been overwhelmed by current applications of fluorescent labeling methods, enzyme labels, and even coenzyme and prosthetic group labels. A variety of alternative labels has also been investigated, including red blood cells, latex particles, viruses, metals, and free radicals. Table 6.1 shows a representative listing of labels used in modem immunoassays.1... 

A typical immunoassay format in a flow-through device has an antibody covalently coupled to the surface of a porous matrix. When the patient sample is added to the matrix, the analyte of interest binds to the antibody. Addition of a second labeled antibody forms a sandwich and traps the label at the position of the first antibody. If the label is gold sol particles or colored latex, the label is directly visualized or quantified by reflectance spectrophotometry in a separate reader, Another important feature of this type of technology is the incorporation of a built-in quality monitor that indicates positive if all the reagents have been stored and the device operated correctly. In all these different formats,... 

Cystatin C has been measured by immunodiffusion or rocket electroimmunoassay, but the methods are too insensitive, and any form of labeled immunometric assay is too cumbersome and time consuming for the response time required. The most practical approaches described are to use a latex particle-enhanced turbidimetric or nephelometric immunoassay. An intraassay precision of less than 3% can be expected at the upper limit of the reference interval ( 1.00mg/L), with less than 4% for the between-day value. Further, cystatin C measurement appears unaffected by the spectral interferences affecting creatinine assays. ... 

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