Novel All-Natural Microcapsules from Gelatin and Shellac for Biorelated Applications

The generation of novel all-natural biopolymeric microcapsules fabricated using natural biopolymers, protein (gelatin) and resin (shellac), is reported. These novel microcapsules are generated using a simple extrusion method wherein the gelatin-shellac mixture is dropped in an acidic medium resulting in an instantaneous solidification of aqueous drops into solid spherical microcapsules that retain their shape on air-drying. The formation of the microcapsules is basically due to the strong interactions between two oppositely charged polymers (as confirmed from isothermal titration calorimetry and infrared spectroscopy) and the instant precipitation of acid-resistant shellac. These novel microcapsules prepared without the help of any cross-linkers or harsh solvent are extensively characterized and several biorelated applications for pharmaceuticals (encapsulation and release of bioactive molecules), foods (loading of colorants and flavors), sensors (encapsulation of pH sensitive dye), and biotechnology (enzyme immobilization) fields are further demonstrated.