微波辅助可控制备单分散球形纳米颗粒气溶胶过程及其生物医学应用研究

Monodisperse metal and metal oxide nanoparticles are extensively applied in the fields of nanomedicine, energy, catalysis, and environment and so on, which require precise control of their composition, crystal phase, crystallinity, size and size distribution, and nanostructure. A microwave radiation enhanced aerosol process will be investigated systematically for preparation of monodisperse nanospheres of controlled properties list above. The moving boundary problem of evaporating water droplets under microwave irradiation is studied by numerical simulation on the coupled mass transfer and heat transfer, bubble generation and growth inside the droplets，and droplet breakage. The influence of precursor composition, residence time, initial droplet size, aerosol concentration and microwave power on the size and size distribution of final aqueous droplets will be studied to clarify the mechanism of droplet breakage under the irradiation. Coagulation constants for aerosol particles at high temperature are to be measured, and the influence of flow pattern on the coagulation will also be investigated. Empirical equations of Cunningham slip correction coefficient will be developed as a function of the Knudsen number by mathematical regression of high-temperature experimental data..L10-FePt and Al2O3 are selected as the model alloy and model oxide to demonstrate the feasibility of the technique to make monodisperse nanoparticles with controlled phase, composition, size, and crystallinity. Chemical vapor deposition and physical vapor deposition techniques are employed separately to deposit carbon and NaCl on aerosol particles in high-temperature tube furnace to prevent the coagulation and sintering during aerosol processing and afterward thermal treatment. Furthermore, aerosol assisted evaporation enhanced self-assembly (EISA) is applied with the aid of microwave irradiation to fabricate monodisperse mesoporous SiO2 nanospheres and 10B doped SiO2 nanoparticles. Monodisperse hollow SiO2 nanoparticles and core-shell structured nanoparticles of controlled particle size and silica shell thickness are prepared with various nano-cores such as Ag and L10-FePt, CuAg alloys of desired composition. The nanoparticles are investigated for antibacterial application, magnetic resonance imaging, ultrasound-microbubble-mediated diagnosis and drug delivery. The successful implementation of this project will provide design data and theoretical guidance for the manufacture of high-performance functional nanoparticles.

单分散金属、氧化物纳米颗粒广泛应用于纳米医药、能源等领域，要求对其组成、晶相、尺寸及纳米结构实现精准控制。拟系统研究微波辐射制备单分散球形纳米颗粒的气溶胶过程。计算机数值模拟微波场下水滴蒸发移动边界的耦合质量传递、热量传递，研究气泡的产生、长大和液滴破碎，研究前驱体组成、停留时间、初始液滴尺寸、气溶胶浓度及微波功率等影响，阐明微波破碎机制。测定高温下气溶胶颗粒的凝并常数，研究流动型态的影响，总结出高温下库宁汉滑移修正系数关于克努森数的经验方程。以单分散L10-FePt和α-Al2O3纳米颗粒制备为例，研究碳沉积和NaCl沉积对气溶胶颗粒凝并和烧结行为的影响。利用气溶胶蒸发自组装技术，可控制备10B掺杂SiO2纳米球,L10-FePt、Ag、CuAg@ SiO2等，探索其抗菌、MRI成像示踪、超声微泡诊疗等纳米生物医学应用。本项目顺利实施将为生产高性能纳米颗粒提供设计依据和理论指导

单分散金属、氧化物纳米颗粒广泛应用于纳米医药、能源等领域，要求对其组成、晶相、尺寸及纳米结构实现精准控制。鉴于此，本项目以可控制备纳米材料颗粒为基础，研究其在生物医学领域的应用。主要进行以下五个方面研究：（1）以共沸蒸馏诱导蒸发自组装法为通用方法，成功合成了MHSs。将模型药物成功包封在MHSs中进行给药测试，其吸附容量大，大大提高了药物的稳定性，延长了释放时间。（2）开发了一种新的冷冻辅助反向微乳液方法，将水溶性酶包裹在HMSNs中，以最大限度地保持酶的生物活性。GOx@HMSNs作为生物传感器具有比较宽的线性范围，有较高的灵敏度。利用脂质体包覆中空介孔二氧化硅纳米载体递送系统可用于超声可及的实体瘤的靶向成像和诊疗。（3）用共沸精馏诱导自组装法制备了L10-FePt 纳米晶，晶型良好，纯度较高。研究了L10-FePt@SiO2 球形纳米颗粒的几种不同的方法，每个方法都有各自的优缺点。最后对制备的L10-FePt@SiO2 进行了体外磁共振成像，图像和数据都表明该材料作为T2 增强对比剂具有研究纳米颗粒从鼻腔嗅觉神经进入大脑动态表征的潜力。（4）考察MRI造影剂经鼻入脑的迁移路径及脑内蓄积成像效果来探索超顺磁性颗粒在小鼠鼠脑嗅觉功能网络的迁徙。分析结果发现，对于锰元素介导的T1-MRI，造影剂粒径越小，其迁移路径及脑内显影效果越好；对于铁元素介导的T2-MRI，造影剂均为纳米粒，入脑效率低，主要在鼻腔周围造影。（5）开发了一种数值方法来描述在各种气溶胶产生条件下与气溶胶辅助EISA相关的热和质量传输。以乙醇-水- NaCl为模型体系，研究了气溶胶液滴的演化过程和核壳结构的形成机制。在此基础上，建立了模拟蒸发的通用计算机程序。通过上述一系列工作，证明了微波破碎的机制。通过气溶胶微波爆破制备纳米粉体，产业化成功。在本项目资助下，发表SCI论文19篇，参加国内外学术会议4次，中国发明专利授权8项；培养硕士研究生16名。项目直接投入经费66万元，支出590906.05元，各项支出基本与预算相符。结余经费69093.95万元，这些款项将用于该项目的后续研究。

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