Biodegradable Stereocomplex Micelles Based on Dextran-block-polylactide as Efficient Drug Deliveries.

Biodegradablestereocomplex micelles (SCMs) based on amphiphilicdextran-block-polylactide (Dex-b-PLA) were designed and used for efficient intracellular drug deliveries.The Dex-b-PLA copolymers were successfully synthesizedby click reaction. The structures of the resultant copolymers wereverified by 1H NMR and FT-IR spectra. The formation ofstable micelles through self-assembly driven by the stereocomplexationbetween enantiomeric l- and d-PLA blocks was characterizedby transmission electron microscopy (TEM), dynamic laser scattering(DLS), and fluorescence techniques. It was interesting to observethat the SCMs showed lower critical micelle concentration values (CMCs)because of the stereocomplex interaction between PLLA and PDLA. Differentialscanning calorimetry (DSC) and X-ray diffraction (XRD) analysis providedinformation on the thermal and crystal properties of the copolymersand SCMs. The improved stability of SCMs should be attractive forintracellular drug delivery. Thus, a model anticancer drug doxorubicin(DOX) was loaded into micelles, and the in vitrodrugrelease in was also studied. The release kinetics of DOX showed DOX-loadedSCMs exhibited slower DOX release. Confocal laser scanning microscopy(CLSM) and flow cytometry studies also showed that the DOX-loadedSCMs exhibited a slower drug release behavior. Meanwhile, the MTTassay demonstrated that DOX-loaded SCMs show lower cellular proliferationinhibition against HepG2. In sum, the micelles through self-assemblydriven by stereocomplex interaction would have great potential tobe used as stable delivery vehicles for pharmaceutical and biomedicalapplications. [ABSTRACT FROM AUTHOR]