Lab M demonstrates its bacterial magnetism

These antibody-coated microscopic paramagnetic beads are used for the rapid immunomagnetic separation of the microorganism under test, eliminating the need for traditional enrichment processes.

In food applications, for example, Captivate can reduce the time required for total viable counts, allowing rapid achievement of a presumptive negative result for pathogens. This can be particularly important in the isolation of Escherichia coli O157:H7 from meat and milk samples. As well as E. coli O157:H7, the range includes Captivate for other E. coli serotypes and the isolation of salmonellas. Lab M also offers a custom coating service.

Captivate beads consist of a magnetite core enveloped by a ceramic zirconium oxide coating and have an average size of 2.5 µm. Each Captivate product is designed for the specific target bacteria and is precoated with the relevant antibody. When mixed with a sample suspension and incubated, the antibody-coated beads bind to cell surface antigens, forming an antibody–antigen complex with the target molecules.

A magnetic concentrator is used to separate the complexes from any background organisms or interfering materials. Subsequent washing removes non-specifically bound material and the beads can be plated on the appropriate selective medium or used in other analyses.

Lab M Tel: +44 (0)161 797 5729 www.labm.com