The pH sensitivity of a series of PbAEs synthesized from primary amines and diacrylates is studied. By changing alkyl groups of the amine monomers, the pKb can be tuned across a broad range (from 3.5 to 7.2). Micelles formed from a PEG‐PbAE block copolymer retain the pH sensitivity of PbAE and can stably load hydrophobic molecules under neutral pH, while quickly dissociate and release their cargoes at pH ≈ 6.0. When the chemotherapy drug DOX is loaded, the micelles show efficient cell proliferation inhibition to HeLa cells and fast intracellular release. Thus, the primary‐amine‐based PbAEs are shown to be promising in the construction of intracellular targeting drug delivery systems.
An amphiphilic diblock copolymer PG‐b‐PCL with well‐controlled structure and pendant hydroxyl groups along hydrophilic block was synthesized by sequential anionic ring‐opening polymerization. The micellization and drug release of PG‐b‐PCL copolymers using pyrene as a fluorescence probe were investigated for determining the influences of copolymer composition and lipase concentration on drug loading capacity and controlled release behavior. The biodegradation of PG‐b‐PCL copolymers was studied with microspheres as research samples. It has been concluded that the polar hydroxyl groups along each repeat unit of hydrophilic PG block in PG‐b‐PCL copolymer have great influences on drug encapsulation, drug release, and enzymatic degradation of micelles and microspheres.
