Recently, different bottom-up techniques were developed to prepare polysaccharide-based particles from solutions of the corresponding polymers.
The different approaches available allow tailoring the size of the particles over two orders of magnitude.
For example, two main concepts were adapted for the preparation of nanoparticles from hydrophobic cellulose esters: The emulsification-evaporation process from a lipophilic solution of the polymer and the solvent-displacement processes from a hydrophilic solution.
These techniques yield, depending on the conditions, particles of a size 50 nm – 1 µm with narrow (even monomodal) particle size distribution. Alternatively, cellulose and hemicellulose particles can be prepared from polymer solutions by the formation of droplets using filament cutting or spinning disk atomization and the subsequent coagulation of the droplets in a non-solvent bath. The particle diameters obtained in this case is dependent on the size of droplets as well as on the coagulation conditions and can be tuned from 50 µm and a few millimeters(micro particles).Particles prepared by the dropping-coagulation method are termed as cellulose beads and feature outstanding high surface areas.