Canadian Forest Service Publications
Encapsulation of microparticles in teardrop shaped polymer capsules of cellular size. 2001. Winder, R.S.; Wheeler, J.J. United States Patent and Trademark Office, Washington. United States Patent 6,248,321 B1. 18 p. (includes: 25 claims, 10 drawing sheets).
Issued by: Pacific Forestry Centre
Catalog ID: 18386
CFS Availability: Order paper copy (free)
Microparticles such as propagules of eukaryotic biocontrol agents are encapsulated in cellular-scale polymer capsules that have a diameter similar to normal eukaryotic cells in a range of about 10 micrometres to about 400 micrometers. The microparticles are encapsulated by adding a hydrophobic dispersion medium such as a mixture of chloroform and hexane or a mixture of corn oil and n-hexadecane having a specific gravity of about 1 and containing an emulsifier such as lecithin to an aqueous suspension of the microparticles and a polymer matrix precursor such as alginate, agitating vigorously to form a stable emulsion of microscopic globules containing a microparticle, and adding the emulsion to an aqueous solution containing a polymerizing agent such as calcium chloride to polymerize and precipitate the globules to form microparticles encapsulated in polymer matrix capsules that may be of a teardrop shape having a length of 40-200% longer than the diameter. Precipitation of the globules is regulated by substantially matching the Specific Gravity of the hydrophobic dispersion medium and the aqueous suspension. The microparticle may be a viable propagule of a weed pathogenic fungus to provide a herbicidal composition.