Colloidal Assembly of Biodegradable Multifunctional Nanoclusters

0968038 Johnston智力优点：纳米技术的一个主要挑战是设计具有多功能性的小于100 nm的稳定颗粒，特别是具有强的光学和磁性。通常的表面活性剂引导原子生长的方法很难获得所需的粒子形态。因此，将开发一种稳健且灵活的替代方案，以将约5 nm的纳米颗粒构建块物理组装成多功能纳米团簇。将开发这种胶体动力学和界面组装概念，以同时获得低于100 nm的尺寸和极高的金和氧化铁颗粒负载量（80%），以产生强的光学（NIR吸收）和磁性（磁矩/体积和自旋-自旋弛豫率，r2）特性。此外，这些簇在可生物降解的聚合物稳定剂分解后将分解回原始的初级纳米颗粒，这对于它们向生物医学领域的转化非常重要。 具体而言，将通过调整胶体相互作用以控制簇生长、尺寸和形态来形成具有高负载的紧密排列的金和氧化铁纳米颗粒的纳米簇。弱吸附的聚合物稳定剂将有利于更高的无机颗粒负载比在平衡自组装的情况下，以及集群生物降解。簇中每种类型的纳米颗粒的空间取向将通过高分辨率TEM和TEM断层扫描在各种倾斜角下针对各种纳米颗粒组合物、表面涂层和稳定聚合物进行分析。近红外表面等离子体共振和自旋自旋磁弛豫率将被测量和解释的集群形态。将在溶液中用光谱学和动态光散射以及在活细胞中用高光谱光学成像和透射电子显微镜监测簇的解聚。更广泛的影响：这种强大的动力学组装平台，用于设计具有高无机颗粒负载量的可生物降解纳米团簇，以实现强大的多功能特性，将为微电子，传感器，成像和光电子学提供广泛的机会。这种胶体方法的简单性和灵活性，以形成新的类别的纳米团簇可能会产生大量的实验和理论研究，以了解光学/磁性和纳米团簇形态之间的关系。此外，光学/磁性纳米颗粒可以提供现代医学的主要挑战之一的解决方案，有效地递送治疗剂和病理学的分子特异性治疗，并使用实时成像（光声成像和MRI）进行指导和监测。纳米团簇生物降解成初级纳米颗粒可以克服纳米技术中的主要障碍，即在人类和更广泛的环境中积累时的毒性。 一个关键的主题将是向年轻学生展示工程可以在改善医疗保健方面发挥重要作用，通过将化学和生物学中的科学概念结合起来解决实际问题。PI将开发教育材料，实验室实验，并为全国知名的UTeach推广计划提供学生教师，该计划为本科生提供奥斯汀独立学区科学课程的志愿者教师。在UTeach青年科学家夏令营中，来自西班牙裔小学的六年级学生将来到德克萨斯大学参加为期一周的实践探究式科学课程，强调学术严谨性。 PI将在科学课程和夏令营中增加工程部分，以补充目前在化学和生物学方面的努力。

0968038JohnstonIntellectual Merit:A major challenge in nanotechnology is to design stable particles smaller than 100 nm with multifunctionality, and in particular, strong optical and magnetic properties. It is difficult to achieve the required particle morphology in the common approach of atomic growth guided by surfactants. Thus, a robust and flexible alternative will be developed to assemble ~5 nm nanoparticle building blocks physically into multifunctional nanoclusters. This colloidal kinetic and interfacial assembly concept will be developed to obtain simultaneously sizes below 100 nm and extremely high loadings (80%) of gold and iron oxide particles to produce strong optical (NIR absorbance) and magnetic (magnetic moment/volume and spin-spin relaxivity, r2) properties. In addition, these clusters will disassemble back into the original primary nanoparticles upon breakdown of biodegradable polymer stabilizers, which is very important for their translation to the biomedical field. Specifically, nanoclusters with high loadings of closely paced gold and iron oxide nanoparticles will be formed by tuning the colloidal interactions to control the cluster growth, size, and morphology. Weakly adsorbed polymer stabilizers will favor much higher inorganic particle loadings than in the case of equilibrium self-assembly, as well as cluster biodegradation. The spatial orientation of each type of nanoparticle in the cluster will be analyzed by high resolution TEM and TEM tomography at various tilt angles for a variety of nanoparticle compositions, surface coatings and stablilizing polymers. The NIR surface plasmon resonance and the spin-spin magnetic relaxivity will be measured and explained in terms of the cluster morphology. The cluster de-aggregation will be monitored in solution with spectroscopy and dynamic light scattering and in live cells with hyperspectral optical imaging and transmission electron microscopy. Broader Impact: This robust kinetic assembly platform for the design of biodegradable nanoclusters with high inorganic particle loadings for strong multifunctional properties will offer broad opportunities in microelectronics, sensors, imaging and optoelectronics. The simplicity and flexibility of this colloidal approach to form novel classes of nanoclusters will likely spawn numerous experimental and theoretical studies to understand the relationship between the optical/magnetic properties and nanocluster morphology. Furthermore, the optical/magnetic nanoparticles can provide solutions to one of the major challenges of modern medicine efficient delivery of therapeutics and molecular specific treatment of pathology with real-time imaging (photoacoustic imaging and MRI) for guidance and monitoring. The biodegradation of nanoclusters into primary nanoparticles can overcome the major roadblock in nanotechnology that is toxicity upon accumulation in humans and in the broader environment. A key theme will be to show young students that engineering can play a major role in improving health care, by integrating scientific concepts in chemistry and biology to address practical problems. The PIs will develop educational material, laboratory experiments and provide student teachers for the nationally renowned UTeach Outreach program, which provides undergraduate students to serve as volunteer instructors for science lessons in the Austin Independent School District. In the UTeach Young Scientists Summer Camps, rising sixth grade students from heavily Hispanic elementary Schools will come to University of Texas for one week to participate in hands-on inquiry-based science lessons that stress academic rigor. The PIs will add an engineering component to the science lessons and the summer camp to complement current efforts in chemistry and biology.