Figure 7.

Proposed release mechanisms of encapsulated drug molecules D from our PCN and Needham’s lipid-coated, drug-loaded microgel. (A) In PCN, protonation of the substituents in the cross-linked polymer shell induces intramolecular hydrogen bonding and densification that “squeeze” the lipid membrane, leading to an eventual release of drug molecules from the core. (B) In a drug-loaded microgel, the swollen gel particle becomes densified under acidic condition and is trapped in this form by a lipid coating that inhibits the reversed swelling. Subsequently, the lipid membrane can be ruptured by electroporation while under neutral pH, leading to a gel swelling that can release the trapped drug molecules.