Alternatives to radioimmunoassay: labels and methods.

Abstract

We review the following labels used as substitutes for radioisotopes in immunoassay systems: bacteriophages, chemiluminescence precursors, fluorochromes, fluorogens, fluorescence quenchers, enzymes, coenzymes, inhibitors, substrates, various particulates, metal atoms, and stable free radicals. New methods for performing immunoassays with these labels are described where appropriate. Methods that require no separation steps and offer special promise for easy automation are noted.

(N-Succinimidyl 4-pentynoate)(hexacarbonyldicobalt): a transition-metal carbonyl complex having similar uses to the Bolton-Hunter reagent

“…The labeling of biomolecules with radionuclides and other conjugates is an extremely important field for clinical diagnosis and there is a constant search for new and more sensitive analytical techniques for the detection of biological tracers (1). The Bolton-Hunter reagent, 125Ilabeled N-succinimidyl 3-(4-hydroxyphenyl)propionate (1), was the first conjugation species to be used extensively 1 to prepare high-activity, high-specificity, radiolabeled tracers for immunoassay (2,3).…”

“…The labeling of biomolecules with radionuclides and other conjugates is an extremely important field for clinical diagnosis and there is a constant search for new and more sensitive analytical techniques for the detection of biological tracers (1). The Bolton-Hunter reagent, 125Ilabeled N-succinimidyl 3-(4-hydroxyphenyl)propionate (1), was the first conjugation species to be used extensively 1 to prepare high-activity, high-specificity, radiolabeled tracers for immunoassay (2,3). However, chiefly because of the attendant legal and technical problems associated with 125I and other radioisotopes (4), considerable effort is being placed nowadays into the development of nonradioactive tracers for clinical diagnosis.…”

“…Figure1. Expansion of the y(CO) region of the FT-IR spectrum of 6 (c = "7 ;1.6 pmol injected; CC14 solution; 20-mm gold light-pipe cell; 10 scans; 4 cm'1 resolution).…”

Steroid Assays in Paediatric Endocrinology

“…Unusually low results for steroids can be found ( 89 ) and appropriate steps need to be taken to counteract the heterophilic antibodies ( 90 , 91 ). To overcome concerns over safety and stability of reagents, alternative labels were introduced (chemiluminescent, fluorescent, as examples) ( 92 ), and from that time automation gradually took over (reviewed by Wheeler # 93 ). With the introduction of multi-channel automated analysers, it became possible for the laboratory to analyse all the components for results of a panel of hormones (cortisol, progesterone, oestradiol, testosterone, T3, free T4, DHAS, LH, FSH, TSH, prolactin, ACTH) in one sample over a few hours.…”

Labeling of Proteins by a Triosmium Carbonyl Cluster via a Bolton−Hunter-like Procedure

“…Owing to legal and technical problems associated with radioactivity, the optimization of “cold” labeling procedures has captured the interest of many research groups in the last two decades . In 1977, Cais et al .…”