| Nanomaterial, as the basis of nanotechnology, is the most dynamic element inthe research and is very promising for practical application. It is not only the mostinfluential part for the future social and economic development, but also animportant material foundation for interdisciplinary fusion of physics, chemistry,information technology, biotechnology, medicine and other fields and their furtherdevelopment. The research area and connotation of nanomaterial has beencontinuously expanded. Multifunctional nanocomposites with low-dimensional andintelligent features have received considerable attention in recent years. They notonly have the special properties of nanomaterial, but also can acquire optimizedoptical, electrical, magnetic, and biological properties by combining the respectivefunction of different component organically, and meanwhile keep their originalphysical and chemical characteristics maintained. They have the advantages of boththe nanomaterial and functional material, so they have become one of the mostpromising materials, and exhibit great potential in many applications, such asbiology, medicine, chemistry, environment, energy and other areas. Aiming at thisimportant research direction, we start from the design and synthesis of functionalmaterials and nanocomposites. Surrounding the multifunctional nanocomposites, this dissertation presents a systematic research about their synthesis and characterizationas well as magnetic, optical, and sensing performance. The major achievementobtained is as follow:1. Core-shell magnetic mesoporous silica nanocomposites were prepared bysolvothermal reaction, sol-gel technology and surfactant template method. Thennovel multifunctional nanocomposites were fabricated by covalent coupling of thedesigned pyrene-based receptor within the channels of magnetic mesoporous silicananocomposites. This multifunctional nanomaterial shows excellent fluorescencesensing properties that allow for highly sensitive and selective Hg2+detection. Adetection limit of1.72ppb is obtained, which is sufficient to sense the Hg2+concentration in drinking water with respect to U.S. EPA limit (~2ppb). Thefluorescent sensing responses for Hg2+are reversible and stable over a broad pHrange and MMS-Py demonstrates its excellent recyclability. Moreover, MMS-Pyexhibits high performance in convenient magnetic separability, and can be used as anabsorbent for fast and efficient removal of Hg2+. This multifunctional nanocompositemay find potential applications for simple detection and easy removal of Hg2+inbiological, toxicological, and environmental areas.2. A novel multifunctional Ru(bpy)2Phen-MMS microspheres weresynthesized by immobilization of the as-prepared Ruthenium(II) polypyridylcompounds into the channels of magnetic mesoporous silica nanocomposites (MMS)using a simple solution based method. The well-designed multifunctionalnanocomposites show superparamagnetic behavior, ordered mesoporouscharacteristics, and exhibit a strong red-orange metal-to-ligand charge transferemission. Meanwhile, the obtained nanocomposites give good performance inoxygen sensing with practical sensitivity (I0/I100=5.2), short response/recoverytimes (t↓=6s and t↑=12s), and good Stern Volmer characteristics (R2=0.9995). In addition, they exhibit good stability and reproducibility. The magnetic,mesoporous, luminescent, and oxygen-sensing properties of this multifunctionalnanostructure make it hold great promise as a novel oxygen-sensing system for environmental monitoring and biosensor.3. We have demonstrated a successful synthesis of azobenzene functionalizedmagnetic mesoporous silica nanocomposites (Azo-MMS) with targeted delivery andlight-controlled release property for the first time, which was simply constructed byusing the nonporous silica coated Fe3O4as the core,4-phenylazoanilinefunctionalized hydrolysable compounds (Azo-Si) as the sol gel precursor,tetraethoxysilane (TEOS) as the silica source, and cetyltrimethylammonium bromide(CTAB) was selected as the organic template for the formation of the outermesoporous silica layer. This synthetic procedure is fast, simple and low cost. Theobtained nanocomposites possess ordered hexagonal mesopores, superparamagneticand light-responsive properties. The nanocomposites can be used as an effectivecarrier for loading and releasing the cargo molecules. Irradiation with visible light(450nm) triggers the release of Rhodamine6G loaded in the mesopores, and thenanocomposites enable remotely controlled release of the cargos―on-off‖at will.Additionally, we have shown the feasibility of using this composite as a targeteddelivery system by external magnetic field. This composite was also applied to theloading and controlled release of ibuprofen (IBU), demonstrating its potential forapplications in drug delivery... |
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