Choosing polymer microspheres for carrying out the latex agglutination reaction in plates

Abstract

Serological tests based on an agglutination reaction are commonly applied in clinical laboratories for the diagnosis of various infectious diseases. There is a wide selection of microsphere-based diagnostic agglutination tests (yes/no results) and assays (quantitative results) worldwide. However, due to rapidity and no need for special equipment passive hemagglutination tests are still the most frequently used routine tests in Russia. These hemagglutination tests are run in 96-well microplates with V-shaped bottoms. The substitution of red blood cells for polymer microspheres in such semi-quantitative tests is difficult due to a number of reasons. When choosing the appropriate microspheres for rapid passive latex agglutination tests, it is important to consider such variables as their size (and size distribution), density and colloidal stability. In our study we showed the development of rapid (1-3 hours) passive latex agglutination tests based on the knowledge of sedimentation stability of polymer suspensions. We studied sedimentation rates of sheep and chicken erythrocytes used in passive hemagglutination tests and identified the required intervals of sedimentation rate for polymer microspheres. Based on these dates a theoretical model of polymer microsphere motion within a V-shaped well was proposed, which revealed that the formation of a lattice in the passive latex agglutination reaction takes place not in the volume of the well, but on the surface of the well bottom.

Keywords

• passive hemagglutination reaction, passive latex agglutination reaction, polymer microspheres.