Stimulus-Responsive Degradable Polylactide-Based Block Copolymer Nanoassemblies for Controlled/Enhanced Drug Delivery

Polylactide (PLA) is biocompatible and FDA-approved for clinical use and thus has been a choice of the materials valuable for extensive applications in biomedical fields. However, conventionally designed PLA-based amphiphilic block copolymer (AB?) nanoassemblies exhibit slow and uncontrolled release of encapsulated drugs because of the slow biodegradation of hydrophobic PLA in physiological conditions. To improve potentials for clinical use and commercialization of conventional PLA-based nanoassemblies, stimulus-responsive degradation (SRD) platform has been introduced into the design of PLA-based nanoassemblies for enhanced/controlled release of encapsulated drugs. This review summarizes recent strategies that allow for the development of PLA-based ABPs and their self assembled nanostructures exhibiting SRD-induced enhanced drug release. The review focuses on the design, synthesis, and evaluation of the nanoassemblies as intracellular drug delivery nanocarriers for cancer therapy. Further, the outlook is briefly discussed on the important aspects for the current and future development of more effective SRD PLA-based nanoassemblies toward tumor-targeting intracellular drug delivery.