Compared 17-AAG in vitro with free DOX, DOX-loaded micelles

exhibited much lower cytotoxicity to HepG2 cells at the same dose of DOX, which was mostly due to the controlled and incomplete release of DOX from micelles in this time frame, as confirmed with in vitro DOX release.The cellular uptake of the micelles was further examined by CLSM measurements. HepG2 cells were cultured with free DOX and DOX-loaded micelles (50 μg/mL of DOX concentration) at 37°C for 4 and 24 h, respectively. The red fluorescence was mainly observed in cytoplasm with a small portion in the nuclei after 4 h (Figure 9A). With further incubation for 24 h in Figure 9B, intense DOX red fluorescence was almost localized in the nuclei, but not so strong as that of free DOX (Figure 9C), indicating ACP-196 purchase that DOX-loaded micelles might not enter the nuclei as quickly as the free DOX. Because DOX is a small molecule, it can be quickly transported into cells

and enter the nuclei through a passive diffusion mechanism. However, DOX-loaded micelles are internalized through an endocytotic pathway and only the released DOX can enter nuclei. Figure 8 In vitro cytotoxicity. Empty micelles after 48 h. At different concentrations of polymer (A) and DOX-loaded micelles after 24 h and 48 h (B) incubation at different concentrations of DOX determined by MTT assay against HepG2 cells. The standard deviation for each data point was averaged three samples (n = 3). Figure 9 CLSM images of HepG2 cells. For incubation with DOX-loaded micelles. For 4 h (A), 24 h (B), and with free DOX for (C) 24 h (red, DOX; blue, Hoechst 33324. Scale bar, 20 μm). Conclusions Serial amphiphilic miktoarm star polymers (PCL)2(PDEAEMA-b-PPEGMA)2 were successfully prepared by a combination of ROP and continuous ARGET ATRP. A good first-order kinetic characteristic was observed for the continuous ARGET ATRP of DEA and PEGMA.

The CMC values of (PCL)2(PDEA-b-PPEGMA)2 were extremely low (0.0024 to 0.0043 mg/mL). The self-assembled empty and DOX-loaded micelles were spherical in morphologies with average sizes of 63 and 110 nm depending on the architecture of the copolymers. 5-FU in vitro The pH responsiveness and in vitro release properties from the micelles exhibited desired pH dependence owing to the protonation of tertiary amine groups of DEA. The in vitro release study showed that the release of DOX at pH 5.0 was much buy MS-275 faster than that at pH 7.4 and pH 6.5. Moreover, in vitro cytotoxicity of DOX-loaded micelles suggested that they could effectively inhibit the growth of cancer cells HepG2 with IC50 of 2.0 μg/mL, indicating that the DOX-loaded (PCL)2(PDEA-b-PPEGMA)2 micelles could exhibit similar antitumor activities to free DOX. Intracellular uptake demonstrated that DOX was delivered into the cells effectively after the cells were incubated with DOX-loaded micelles.