EAPSI: Stimuli-responsive capsules from polymer-covered gold nanorods

对外界刺激（如温度、pH值、离子强度、光照或电场的变化）做出反应的“智能”材料是大量研究的主题，其应用范围从人造肌肉到传感器再到治疗药物的输送。该项目将研究由聚合物覆盖的金纳米棒（棒状纳米大小的金颗粒，Au NRs）稳定的水包油水滴的刺激响应行为，这些水滴对温度、盐浓度和光线都有响应。新加坡南洋理工大学的段宏伟博士是聚合物覆盖颗粒组装方面的专家，他将担任这项研究的主持人。在这些液滴的油水界面上放置特殊材料，如Au nmr和聚合物，将提供具有高功能、高响应系统的新材料。将聚合物-纳米颗粒复合材料组装成二维或三维结构，提供了不同于单个组分的特性，这在化学、物理、工程和生物学领域引起了广泛的兴趣。该项目将涉及将盐和温度响应两性离子聚合物结合到Au核磁共振上。聚合物化学的多功能性使其可以很容易地将刺激响应官能团与促进交联和与金结合的部分结合成相同的聚合物，而金核磁共振是智能材料的理想成分，因为它们具有生物相容性和固有的光热转换能力。纳米复合材料将在油水界面组装在液滴上，随后交联成机械坚固的胶囊。这些组件对外部刺激（即盐、温度和光）的响应将通过光学显微镜和表面增强拉曼散射（SERS）进行研究。为了演示这些胶囊用于胶囊化的效用，将监测染料的吸收和释放。该奖项由美国国家科学基金会与新加坡国家研究基金会共同资助。

'Smart' materials that respond to external stimuli, such as a change in temperature, pH, ionic strength, light exposure, or electric field, are the subject of a large body of research for applications that range from artificial muscles to sensors to the delivery of therapeutics. This project will investigate the stimuli-responsive behavior of oil-in-water droplets stabilized by polymer-covered gold nanorods (rod-shaped nanometer-sized gold particles, Au NRs), which are responsive to temperature, salt concentration, and light. Dr. Hongwei Duan, an expert in assemblies composed of polymer-covered particles, at Nanyang Technological University in Singapore will served as the host for this research. Placing special materials, such as Au NRs and polymers, at the oil-water interface of these droplets will afford new materials that hold great promise as highly functional, responsive systems.Assembling polymer-nanoparticle composites into two- or three-dimensional structures affords properties distinct from the individual components that are broadly interesting for chemistry, physics, engineering, and biology. This project will involve the incorporation of salt- and temperature-responsive zwitterionic polymers onto Au NRs. The versatility of polymer chemistry lends itself to easily combine stimuli-responsive functional groups with moieties that facilitate cross-linking and binding to gold into the same polymer, while Au NRs are ideal components of smart materials due to their biocompatibility and inherent ability to convert light into heat. The nanocomposites will be assembled at the oil-water interface, on droplets, and subsequently cross-linked into mechanically robust capsules. The response of these assemblies to external stimuli (i.e. salt, temperature, and light) will be studied by optical microscopy and by surface enhanced Raman scattering (SERS). To demonstrate the utility of these capsules for encapsulation, the uptake and release of a dye will be monitored. This NSF EAPSI award is funded in collaboration with the National Research Foundation of Singapore.