Particle counting immunoassay. IV. The use of F(ab′)2 fragments and Nϵ-chloroacetyl lysine N-carboxyanhydride for their coupling to polystyrene latex particles

Particle Enhanced Light Scattering Immunoassay

“…56 Using covalent coupling they demonstrated a calibration stability in excess of 4 months. Kapmeyer et al showed similar results, using a different particle and coupling chemistry."…”

“…The use of non-aqueous solvents as with the mixed anhydride reaction can cause flocculation of the particles during the reaction;" Other coupling chemistries have also been used, some to address particular interferences such as rheumatoid factor. 56 Finally. there can be special difficulties associated with the coupling of monoclonal antibodies to latex particles, leading one group to file a patent application for their process.…”

“…55 Despite using two sources of particles, the literature surrounding this technique suggests that its limited use is more due to problems with the particles themselves than the detection system since there are a lot of difficulties with non-specific aggregation reactions and rheumatoid factor interference. 56 If different particle surface chemistries were to be used this might become a more viable automated light scattering detection system. It has also been suggested that counting aggregated particles could produce approximately a lOO-fold increase in sensitivity, although this has yet to be demonstrated.…”

Particle counting immunoassay (PACIA) V‐ its applicationto the determination of human placental lactogen

“…The supernatant was dialysed overnight at 4 C against 0.9% NaC1 to remove traces of Rivanol. This IgG solution was used for coating latex and for the preparation of F(ab')2 fragments by pepsin digestion as described elsewhere [2].…”