A Continuous-flow Micro Double Diffusion Technique with Cellulose Acetate

Abstract

THE value of the Ouchterlony double diffusion test in the analysis of antigen-antibody reactions is well established. In the micro modification, introduced by Wads-worth¹ and developed by Crowle², a continuous-flow diffusion system was achieved by using wells made in ‘Perspex’ templates. Relatively large volumes of reactants diffuse under hydrostatic pressure into a thin layer of agar, greatly increasing the sensitivity and resolution of the test while economizing on reagents³. However, the use of agar in the micro-technique has certain disadvantages. Primarily, there is the considerable risk of complete loss of the reaction due either to tearing of the fragile agar layer when the template is removed, or to its loosening and washing off during the staining procedures. Splitting and distortion of the agar layer during drying may also occur. Secondly, the test is relatively inflexible in that the pH. and electrolyte concentration of the agar cannot easily be varied, and, finally, variations are encountered with different batches of agar both as regards their mechanical stability and the reactions developing in them³.