| abstract |
A method for producing foams containing biological materials is described. A solid or semi-solid paste is formed by combining biologically active material with a protecting agent in an aqueous solvent. The paste formed is allowed to set, and may optionally then be apportioned into the desired shape. The paste may be frozen to allow formation of ice crystals to act as porogens. Subsequently, the paste is exposed to travelling wave radiant energy under vacuum (t-REV) for drying. This causes the solvent to boil off, leaving dried material containing the biologically active material, the protecting agent, and a relatively low water content. Biologically active materials which can be used include cells, microbial cultures, live attenuated microbes, probiotics, yeasts, enzymes, vaccines, proteins, and any heat-sensitive biological material. By directing energy via a travelling wave through a sample, good control of temperature and process conditions can be achieved. The method provides an alternative to the conventional methods of particulate leaching or freeze drying. |