Tumor microenvironment sensitive doxorubicin delivery and release to glioma using angiopep-2 decorated gold nanoparticles.

Glioma is still hard to be treated due to their complex microenvironment. In this study, a gold nanoparticle-based delivery system was developed. The system, An-PEG-DOX-AuNPs, was loaded with doxorubicin (DOX) through hydrazone, an acid-responsive linker, and was functionalized with angiopep-2, a specific ligand of low density lipoprotein receptor-related protein-1 (LRP1), which could mediate the system to penetrate blood brain barrier and target to glioma cells. The particle size of An-PEG-DOX-AuNPs was 39.9 nm with a zeta potential of -19.3 mV, while the DOX loading capacity was 9.7%. In vitro, the release of DOX from DOX-AuNPs was pH-dependent. At lower pH values, especially 5.0 and 6.0, release of DOX was much quicker than that at pH 6.8 and 7.4. After coating with PEG, the acid-responsive release of DOX from PEG-DOX-AuNPs was almost the same as that from DOX-AuNPs. Cellular uptake study showed obviously higher intensity of intracellular An-PEG-DOX-AuNPs compared with PEG-DOX-AuNPs. In vivo, An-PEG-DOX-AuNPs could distribute into glioma at a higher intensity than that of PEG-DOX-AuNPs and free DOX. Correspondingly, glioma-bearing mice treated with An-PEG-DOX-AuNPs displayed the longest median survival time, which was 2.89-fold longer than that of saline. In conclusion, An-PEG-DOX-AuNPs could specifically deliver and release DOX in glioma and significantly expand the median survival time of glioma-bearing mice.