We report a novel photodynamic therapy (PDT) drug-carrier system, whereby third-generation (G3) polyamidoamine (PAMAM) was successfully grafted to the surface of porous hollow silica nanoparticles (PHSNPs), followed by the attachment of gluconic acid (GA) for surface charge tuning. The composite G3-PAMAM-grafted PHSNPs (denoted as G3-PHSNPs) with a diameter range of 100–200 nm and about 30 nm sized shell thickness retain bimodal pore structures (e.g. inner voids and porous structure of the shells) and PAMAM-functionalized outer layer with a large number of amino groups, allowing high loading efficacy of aluminum phthalocyanine tetrasulfonate (AlPcS4) and its effective release to target tissue. The GA-induced G3-PHSNPs were evidenced to be able to favorably cross tumor cell walls and enter into the cell interior. The generation of singlet oxygen (1O2) from AlPcS4-GA-G3-PHSNPs under visible light excitation was detected by the in situ electron spin resonance measurements and the oxidative reaction between the generated 1O2 and a chemical probe. In vitro cellular experiments showed that the photosensitive GA-G3-PHSNPs exhibited a good biocompatibility in the dark and a higher killing efficacy against MCF-7 tumor cells upon irradiation as compared with free AlPcS4, which implies that the preformed photosensitive drug-carrier system might be potentially applicable in PDT.
Iodine-doped TiO2 nanocrystallites (denoted as I-TNCs) were prepared via a newly developed triblock copolymer-mediated sol–gel method at a temperature of 393 K. I-doping, crystallization and the formation of porous structure have been simultaneously achieved. The obtained particles were characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and UV–vis spectrophotometer. The results indicated that the as-prepared I-TNCs possessed a diameter of ca. 5 nm with anatase crystalline structure and a specific surface area of over 200 m2 g−1. The presence of iodine expanded the photoresponse in visible light range, and led to enrich in surface hydroxyl group on the TiO2 surface. Compared with the commercial photocatalyst P25, the I-TNCs significantly enhanced the photocatalytic efficiency in the degradation of rhodamine B and 2,4-dichlorophenol, and the I-TNCs with 2.5 mol% doping ratio exhibited the best photocatalytic activity.
Two kinds of inorganic/organic hybrid composites based on mesoporous silica nanotubes (MSNTs) and pH-responsive polyelectrolytes have been developed as pH-controlled drug delivery systems via the layer by layer self-assembly technique. One system was based on alternatively loading poly(allylamine hydrochloride) and sodium poly(styrene sulfonate) onto as-prepared MSNTs to load and release the positively charged drug doxorubicin. The other system was synthesized by alternately coating sodium alginate and chitosan onto amine-functionalized MSNTs, which were used as vehicles for the loading and release of the negatively charged model drug sodium fluorescein. Controlled release of the drug molecules from these delivery systems was achieved by changing the pH value of the release medium. The results of in vitro cell cytotoxicity assays indicated that the cell killing efficacy of the loaded doxorubicin against human fibrosarcoma (HT-1080) and human breast adenocarcinoma (MCF-7) cells was pH dependent. Thus, these hybrid composites could be potentially applicable as pH-controlled drug delivery systems.
![7'-METHYLSPIRO[1,3-DIHYDROINDENE-2,3'-2,4-DIHYDRO-1,5-BENZODITHIEPINE]](http://img.cochemist.com/ccimg/7300/7228-67-3.png)
![7'-METHYLSPIRO[1,3-DIHYDROINDENE-2,3'-2,4-DIHYDRO-1,5-BENZODITHIEPINE]](http://img.cochemist.com/ccimg/7300/7228-67-3_b.png)
