Measurement of chemoattractant concentration profiles and diffusion coefficient in agarose

Migration of leukocytes is influenced by both the concentration and gradient of a chemoattractant. In the under-agarose assay, attractant diffuses through the medium away from the attractant well. For complete analysis of assay data, the diffusion coefficient of the attractant in the assay system must be known, and the attractant concentration profiles must be mathematically predictable. This paper describes a method whereby the diffusion coefficient of a chemoattractant through agarose may be determined, by measurement of attractant concentration profiles. The diffusion coefficient of FNLLP was found to be D = 1.0 X 10(-5) cm2/s at 37 degrees C. In addition it was found that the concentration profiles can be satisfactorily predicted by solution of the diffusion equation with appropriate boundary conditions.