Target-specific cellular uptake of folate-decorated biodegradable polymer micelles

For cancer therapy, folate (FA) and β-cyclodextrin (β-CD) decorated micelles based on the biodegradable pluronic F127-b-poly(ε-caprolactone) copolymer were fabricated. These micelles were measured by dynamic light scattering measurements and atomic force microscopy. The in vitro release of doxorubicin hydrochloride (DOX·HCl) from the biodegradable polymer micelles was performed in a phosphate-buffered saline solution at pH 7.4 and acetate buffer solution at pH 5.0 at the temperatures of 4, 25, and 37 °C, and the results show that the release was obviously influenced by the pH and temperature. The material cytotoxicity and the tumor cell growth inhibition assays of DOX·HCl-loaded micelles were studied with the human hepatoblastoma cell line (HepG2), the lung epithelial cancer cell line (A549), and human nasopharyngeal epidermoid carcinoma cells (KB) and fibroblast normal cells using fluorescence microscopy as well as confocal laser scanning microscopy. The cellular uptake was quantitatively analyzed to further evaluate the active targeting behaviors of the micelles by flow cytometry. These quantitative and qualitative results of cellular uptake of the micelles provide evidence for the different targeting efficiencies of FA decoration for HepG2, KB, and A549 tumor cells as well as fibroblast normal cells. It also suggested that FA- and β-CD-decorated doxorubicin-loaded micelles may have great potential as nanocarriers for targeted drug delivery.