Optimization of Protease-Sensitivity of Polymer Vesicles

Polymer vesicles can be functionalized protease-sensitive. The self-assembling unit (block copolymer) contains a peptide substrate of chymotrypsin which is linked between PEG and PCL blocks. The hydrophilic-hydrophobic balance required to form stable vesicles is destroyed upon proteolysis, and hence, the encapsulant inside the vesicles is released. The protease sensitivity is expected to be dependent on the surface area for protease actions and mole fraction of block copolymer containing the peptide substrate. To test our hypotheses, polymer vesicles are extruded to yield different sizes in order to vary the total surface area and co-assemble with block copolymer without the peptide substrate respectively. The protease-sensitivity is monitored by the release kinetics of encapsulated dye in the presence of the protease.