Modification of liposome surface with pH-responsive polyampholytes for the controlled-release of drugs

Ampholytic polymers comprised of 2-(diethylamino)ethyl methacrylate (DEAEMA) and acrylic acid (AA) in varying molar ratios were used to modify egg yolk phosphatidylcholine (EYPC) liposomes previously encapsulated with pyranine. The modified EYPC liposomes were found to be pH responsive. The critical pH values at which the pyranine release from these liposomes at 37 °C were observed to decrease with increasing DEAEMA content in the polymers. Explanations were given for these phenomena

In Vitro Sonodynamic Therapeutic Effect of Polyion Complex Micelles Incorporating Titanium Dioxide Nanoparticles

Titanium dioxide nanoparticles (TiO2 NPs) can act as sonosensitizers, generating reactive oxygen species under ultrasound irradiation, for use in sonodynamic therapy. For TiO2 NPs delivery, we prepared polyion complex micelles incorporating TiO2 NPs (TiO2 NPs-PIC micelles) by mixing TiO2 NPs with polyallylamine bearing poly(ethylene glycol) grafts. In this study, the effects of polymer composition and ultrasound irradiation conditions on the sonodynamic therapeutic effect toward HeLa cells were evaluated experimentally using cell viability evaluation, intracellular distribution observation, and a cell staining assay. TiO2 NPs-PIC micelles with widely distributed features induced a significant decrease in cell viability under ultrasound irradiation. Furthermore, prolonging the irradiation time killed cells more effectively than did increasing the ultrasound power. The combination of TiO2 NP-PIC micelles and ultrasound irradiation was confirmed to induce apoptotic cell death