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Abstract

Spherical microcapsules containing biological material such as tissue or living cells are formed with a diameter of less than 300 .mu.m using a microcapsule generating system containing an air knife. The air knife is formed by an air sleeve positioned eccentrically around a needle. An encapsulating material such as an alginate solution containing the biological material to be encapsulated is forced through the needle, while pressurized air is introduced into the air sleeve and flows out an end opening of the sleeve in which the needle is positioned. The pressurized air breaks up the alginate being discharged from the needle. The resultant alginate droplets fall into a collecting tank where they contact a gelling medium, such as CaCl.sub.2, so that the outer surface of these droplets harden and microcapsules are formed. In addition to being eccentrically positioned to facilitate very small droplet formation, the needle preferably has a beveled, pointed discharge end surface to enhance droplet size reduction. The beveled end surface of the needle preferably extends beyond the end opening of the sleeve and is positioned facing the center of the air sleeve. The end opening of the air sleeve may also be beveled.

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First Claim