| Mesoporous silica material has become an ideal carrier due to their high surface area, large pore volume, uniform and tunable pore size as well as highly ordered mesostructure, and it shows potential application in the field of adsorption, catalysis, chem/bio sensing, controlled drug delivery and biomimetic nanoassembly. In this thesis, aiming at this important research field, based on a survey of a large number of documents, by focusing on the loading modulation in mesoporous silica and combined with nanomaterial synthesis, controlled loading and release, nanoassembly, several approaches were developed to modulate the molecule loading in mesoporous silica and biomimetic compartment was proposed. Several research works have been performed as following.1. pH and ion strength was utilized to modulate the loading of ionic species in mesoporous silica sphere.Taking MV and NDS as model of cation and anion molecule, the loading of diferent charged ionic species in MCM-41 was investigated. The results showed that, as the pH increased from 3.0 to 8.0, the loading amount of MV increased gradually, while on the contrary, it decreased gradually for NDS. At pH 3.0, the loading amount of NDS was larger than that of MV, while at pH 8.0, the loading amount of MV was larger than that of NDS. That’s because the loading of molecules carrying the opposite charge to the mesochannels were prefered as a result of electrostatic attraction, while the molecules carrying the same charge were hindered outside the channels. When the solution pH changed from 3.0 to 8.0, the silanol groups on the channel wall become deprotonated gradually and the surface charge changed from positively charged to negatively charged, which affected the loading of MV and NDS in the mesochannels. Additionally, the adding of Na Cl screened the charge of the mesochannels and decreased the electrostatic interaction between the guest molecule and the mesochannels, which resulted in a decreasing of the electrostatic rejection and electrostatic accumulation for the molecules carrying the same and the opposite charge to the particle respectively. Thus, pH and ion strength can be employed as a simple approach to modulate the loading of ch arged molecules and their permselectivity in mesoporous materials. This work has a definite guidance function for molecule loading, transport modulation in mesoporous materials.2. Hydroxyapatite sedimentation and pH responsive dissolution was employedfor molecule loading and controlled release in mesoporous silica sphere.Carboxyl group rich poly(acrylic acid)(PAA) was modified electrostatically on the mesoporous silica nanoparticles as the nucleation sites for Ca P heterogeneous nucleation for capping the mesochannels and a pH controlled release system was constructed. First, the mesoporous silica nanoparticles was functionalized with negatively charged PAA via electrostatic interaction. Then, taking the c arboxyl group rich PAA as the nucleation sites for heterogeneous Ca P nucleation, the loading and capping of Ru(bipy)32+in mesoporous silica nanoparticles was achieved and the loading amount reached 37.4 μmol/g. Zeta potential mesurement, FTIR, TEM were employed to characterize the capping process and the release of entraped Ru(bipy)32+at different pH was further investigated. It was found that, the release rate was 19.7% at pH 7.0, while the release rate reached 98.5% at pH 2.0. Because of the mild condition for heterogeneous nucleation, pH-dependent biodegradability and non-cytotoxicity of Ca P, the Ca P based pH controlled release system has the potential to be used in drug delivery in vivo.3. Amine functionalized mesoporous silica sphere was employed as model of phosphate responsive biomimetic compartment.Amine functionalized mesoporous silica sphere was synthesized, and it was utilized as a biomimetic ion channel decorated compartment model based on its structure similarity with biological compartment, core-nanoporous shell structure, high surface area cytoskeleton, ion channel-like nanopores on the surface. The phosphate responsive permeation of guest molecule was also achieved in the biomimetic compartment. The experiment results indicated that in the absence of phosphate ion, the positively charged Ru(bipy)32+was rejected by the amine groups on the outer surface, which acted as a gatekeeper shell, and hindered the its permeation into the inner core. While, in the presence of phosphate, as a result of the specific binding between the anionic phosphate and the amine groups, the surface charge was reversed from positive to negative and the permeation of Ru(bipy)32+was gated. The work emerged as a new routine for constructing biomimetic comparment and it also provides a novel approch for developing responsive nanoreactor.4. Phenylboronic acid functionalized mesoporous silica sphere was employed as a model of dopamine responsive biomimetic compartment.Dopamine-binding phenylboronic acid was modified on mesoporous silica sphere as a gatekeeper shell and a dopamine responsive biomimetic compartment was developled. As the phenylboronic acid is negatively charged due to dissociation, the negatively charged 1, 3, 6, 8-pyrenetetrasulfonic acid(TPSA) was hindered from permeation into the biomimetic compartment. However, in the presence of positively charged dopamine, its specific bind with the negatively charged phenylboronic acid reversed the gatekeeper shell from negative to positive charged and gated the permeation of TPSA into the interior. The dopamine gated permeation phenomenon resembles that in biological system and thus it was taken as a simple model for dopamine gated ion channel decorated compartm ent. The work shows great promise in the study of dopamine related ion channel and biological compartment.5. Amine functionalized mesoporous silica microsphere was employed as a model of ATP responsive biomimetic compartment and its fluorescent visulization study.Micrometer mesoporous silica sphere was synthesized and amine group was functionlized on the outer surface to constructe a biomimetic ATP responsive ion channel decorated compartment. The selective outersurface functionalization of amine group was confirmed by laser confocal fluorescence imaging and the functional groups formed a gatekeepshell around the compartment as biological membrane does. In the presence ATP, the permeation amount of Ru(bipy)32+increased gradully and reached 0.8 μmol/g at 5 m M ATP. That’s because the surface amine group was positively charged and the permeation of Ru(bipy)32+was hindered.Then, the added ATP reversed the surface charge because of electrostatic and hydrogen bonding with the amine groups, which gated the permeation of Ru(bipy)32+. The laser confocal fluorescence imaging showed that the permeated guest molecules distributed uniformly in the biomimetic compartment and the fluorescent intensity increased gradully as the concentration of ATP increased. This work provided a simple model for ATP gated ion channel decorated compartment in vitro and the fluorescent visualization method provides a forcible tool for stud ying the mesoporous silica based biomimetic compartment. |
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