Calcium alginate capsules containing a hydrophilic polymer for the encapsulation of swine spermatozoa

A preparation method of calcium alginate beads containing swine spermatozoa was developed. A suspension usually employed for artificial insemination and containing living spermatozoa, to which was added hydroxypropylmethylcellulose and calcium chloride, was dropped into a sodium alginate solution. Calcium ions diffusing out of the droplets, reacted with the sodium alginate, leading to the formation of a water-insoluble calcium alginate gel membrane. Half of the capsules obtained was cross-linked by interfacial polymerization using an aqueous solution of protamine sulphate. The two kinds of capsules (cross-linked and not) containing spermatozoa were then transferred to a suitable extender for swine sperm and their morphology (scanning electron microscope) and in vitro sperm viability (survival time, motility and acrosomal integrity) was studied.