Tetronic capped mesoporous silica nanoparticles for drug delivery

In this study, Tetronic capped mesoporous silica nanoparticles are synthesized and characterized. The efficiency of the gating mechanism is investigated for drug delivery purposes. For this reason, mesoporous silica nanoparticles (MSNs) are produced and coated with Tetronic as gates. Pluronic is also used as an alternative copolymer to compare the results with Tetronic. Two approaches are used to gate the MSNs, which are the physical attachment method and the covalent bonding method. For the physical attachment method, hydrophobic MSNs (hMSNs), in other words, octyl modified MSNs are produced. By making use of the hydrophobic/hydrophilic nature of the copolymers, physical attraction between PPO (hydrophobic) part of the copolymers and the hydrophobic surface of hMSN is achieved. In order to investigate the gating mechanism, efficiency of the physical attachment method, hMSNs are loaded with curcumin before gating with Tetronics. After coating the surface with the copolymer, release experiments at different temperature and pH values are performed and analyzed with UV-Vis spectrophotometry. The highest release rate is obtained at 37℃ and pH 4.8 for Tetronic and at 43℃ and pH 7.4 for Pluronic. In the chemical method, after amination and carboxylation of both MSNs and copolymers, covalent bonding is achieved between MSNs and copolymers through the click chemistry. The success of carboxylation and amination of the materials is confirmed with FTIR spectoscopy. For carboxyl functionalized MSNs and aminated Tetronics / Pluronics, release experiments are conducted using arginine. The highest release rate is achieved at 37℃ and pH 4.8 for MSNCOOH-T1107NH2 and the minimum release data is obtained at 37℃ and pH 4.8 for MSNCOOH-F127NH2. Finally, in order to investigate the toxicity of nanoparticles, Saccharomyces cerevisiae is used as a model cell and CFU analysis is performed. Physical attachment method is observed to be more toxic compared to the chemical attachment method.