| In recent years, the composite fluorescent silica nanoparticles has been widely used in biomedical research. Especially in terms of drug carrier therapies, the composite fluorescent silica nanoparticles can be used as a drug carrier, but also a fluorescent tracer. But the traditional composite fluorescent silica nanoparticles also have many shortcomings in the practical applications, such as the known toxicity,potential environmental hazards, chemical stability, etc. Therefore, the purpose of this paper is to design and synthesis of a new type of composite fluorescent silica nanoparticles with non-toxic, eco-friendly, chemical stability and excellent fluorescence properties. And study its fluorescence, drug loading and in vitro controlled-release properties. The main work are as follows:1. First, we synthesized GO with graphite powders as raw materials, and then cut it into GQDs by solvothermal cutting method. Second, we used different characterization methods for characterizing and analysing the structure and fluorescence properties of GQDs. The results showing that the GQDs has a kind of uniform and single or double spherical lamellar structures, and the particle size and thickness are about 22~36 nm and 1~2 nm,respectively. The GQDs shows a good solubility in water, and a good monodisperse property in ethanol; It also exhibits excellent fluorescence properties, such as the luminous characteristics with excitation wavelength dependence, fluorescence intensity has a p H dependence, fluorescence intensity is not affected by the influence of ionic strength. Which indicated that GQDs can be used as a kind of excellent fluorescence tracer.2. We synthesized Si O2/GQDs(S-G) nanocomposite particles via the electrostatic interaction between GQDs and Si O2, and then used different characterization methods for characterizing and analysing the structure and fluorescence properties of S-G. The results showing that the S-G has a kind of uniform structure, and the particle size is about 90~110 nm. The S-G is a kind of high specific surface area and pore volume, also a narrow pore size distribution of mesoporous structure. The S-G shows a good monodisperse property in ethanol; Italso exhibits excellent fluorescence properties, such as the luminous characteristics with excitation wavelength dependence, fluorescence intensity has a p H dependence,fluorescence intensity is not affected by the influence of ionic strength, fluorescence intensity increase as the mass ratio of GQDs/Si O2 increase. Which indicated that S-G can be used as fluorescent tracers and drug carriers at the same time.3. S-G has a high drug loading capacity, and the aspirin loading capacity of the S-G could reach 36.59%, which is twice as much as that of pure MSN(18.26%). It is worth noting that the S-G possess the much higher aspirin loading capacity compared with the previously reported m Si O2-based NPs. And the drug loadings capacity is influenced by the mass ratio of GQDs/Si O2. S-G-asp possess a controlled-release property in vitro. It has a more than 33 h release time under the condition of p H 2.5,p H 5.0 and p H 7.4, and the release rate of S-G-asp decreased with the increased of p H values, which about 95.15% of aspirin released from S-G-asp under the condition of p H 2.5, and about 82.50% and 66.31% under the condition of p H p H 5.0 and 7.4,respectively. The release speed of S-G-asp was influenced by the concentration of Na Cl, the release speed increased as the concentration increased. And the release speed increased as the temperature increased.In summary, we have designed and synthesized a new kind of Si O2/GQDs fluorescent nanocomposite particles. Through silica nanoparticles loaded graphene quantum dots, which show more excellent fluorescent properties, and improve the performance of silica drug-loading nanoparticles; The nanoparticles drug delivery system integrates the function of fluorescence imaging and drug treatment, drug release effect of p H response, which is expected to achieve integration of tumor diagnosis and treatment. |
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