CS based nano-particles/fibers, hydrogels and membranes have been formulated to embed bioactive moieties (hydrophilic, hydrophobic and macromolecules), due to the specific tissue targeting and, sustained/controlled release  Ionic gelation technique, among multiple preparation methods comprising complex coacervation
, ionotropic gelation, self-assembly method through chemical modification, solvent evaporation/diffusion, and emulsion-droplet coalescence, is preferred for its convenience, relative simplicity, and the rid of organic solvents and high temperatures .
Droplet stability is secured by a complex coacervation
process which combines two polymers interacting together in the manner of "molecular velcro tapes" to form an evanescent membrane.
This suggested that the coacervation
between soy protein fractions and chitosan increased the thermal stability of the protein.
Chemical methods tend to be preferred for non-solid core materials and include coacervation
and sol-gel approaches.
Several techniques for manufacturing microspheres have been developed, such as electrospray drying [14, 15], solvent evaporation [16-18], emulsion crosslinking [19, 20], ionic gelation technique , direct dispersion method , microfluidic channels , supercritical carbon dioxide , coacervation
method , and free radical emulsion polymerization .
method was used to produce omega-3 nanocapsules.
Techniques including spray drying, melt extrusion, coacervation
, and aqueous emulsions have been used to generate fragrance-containing microparticles.
The concept of controlled drug delivery was first introduced as a part of pharmaceutical industry via Wurster technique in 1949 and experienced Coacervation
(liquid encapsulation) from 1953, offering microencapsulation technology in 1960 as a milestone in this progress .
Design of nimesulide-chitosan microparticles by pH change coacervation
There are many techniques to carry out the microencapsulation of various compounds and microorganisms, among which there may be mentioned spray drying, extrusion, fluidized bed, simple or complex coacervation
, liposomes, inclusion in complexes (Gouin, 2004), spray coating, interfacial polymerization, and ionic gelation (Thies, 1996), the latter being a developed process for immobilizing a cell, which uses an anionic polymer mainly alginate as component of the membrane, in combination with divalent ions such as calcium to induce gelation (King, 1988).
Nanoparticles are generally prepared by three methods: (i) dispersion of preformed polymers; (ii) polymerization of monomers; and (iii) ionic gelation or coacervation
of hydrophilic polymers.
Pc-1, -2, -4, and -5), invalidating the previous hypothesis of complex coacervation
(separation of two oppositely charged polyelectrolytes into two immiscible aequous phases when the charges of the polyelectrolytes are balanced) as a model for the formation of the glue (Wang and Stewart, 2012).