SEM IMAGING OF POLYSACCHARIDE MICRO AND NANOCAPSULES

Mikro and nanocapsules have shown to be effective protection systems for bioactive substances. For encapsulation, polysaccharides have certain advantages comparing to other materials. They display biocompatibility and biodegradability and have also other beneficial properties, such as antiviral, antibacterial and anticancerogenic activity [1]. One of the most widely used methods for the production of microcapsules is the vibrating nozzle technique. The method is based on the principle of generating droplets from a polymer extruded through a vibrating nozzle. The resulting droplets fall into a gelling bath where they polymerize [2]. By using this technique we produce alginate and alginate/pectin microcapsules in the size range of 0.15-2 mm. Polysaccharide nanocapsules were prepared using emulsification technique. For the preparation of calcium alginate nanocapsules alginate-in-oil nanoemulsion was used. The gelation of alginate droplets and formation of nanocapsules was caused by the addition of CaCl₂nanoparticles [3]. By emulsification technique we produce alginate and alginate/pectin nanocapsules in the size range of 100-500 nm. We improved the matrices by using combinations of different polysaccharides or additional coatings that can be applied on the surface of microcapsules. The size distribution and morphology of micro- and nanocapsules were determined by using scanning electron microscope (SEM). For SEM imaging the suspension containing polysaccharides was frozen in liquid nitrogen and lyophilized. The images showed that by varying different parameters (e.g. homogenization speed) microcapsules and nanocapsules of different size ranges can be produced.

 Prof. Dr. Natasa Poklar Ulrih natasa.poklar@bf.uni-lj.si