Polypeptide Hybrid Particles and Their Constituents

非技术总结：自然界中一些最重要的构建模块和功能引擎是由蛋白质组成的。人工合成的多肽可以通过简单的方法大量生产，它借用蛋白质的结构并保留了许多类似蛋白质的特征，比如旋转光线和对环境中的热或化学变化做出反应的能力。问题是，尽管多肽是非常大的分子，但它们仍然是非常小的东西。这使得它们很难被操纵。这个项目将生物多肽的功能与利用重力或磁场轻松操纵大颗粒结合在一起。这将通过将多肽放置在胶体二氧化硅（本质上是小玻璃球）上来实现，从而产生核壳颗粒。通过调节温度，多肽壳的形状将被改变。这将提供关于形状转变的信息，类似于流感病毒穿透人体所使用的形状转变。由光作用交联的颗粒链将产生几乎均匀的细丝，使聚合物科学进入更容易检查的可见状态，同时促进更大结构的创建。对一种特别有吸引力的水溶性多肽的研究将使人们更好地了解用于制造高强度纤维的聚合物的种类，比如那些编织成防弹背心的聚合物。新的教育和推广活动被纳入，与现实世界的经验和实验室研究相结合。技术概述：这些研究活动将开发和探索在二氧化硅核上具有合成多肽壳的亚微米颗粒，有时带有磁性包裹体。多肽壳使颗粒对温度和分子不对称的良好传感器敏感，而二氧化硅核使这些功能定向到特定位置成为可能。将研究整个颗粒及其单个多肽和二氧化硅组分。具体而言，将进行以下工作：1)通过小角度x射线和中子散射、静态和动态光散射、光学旋转色散和核磁共振评估核芯半径、壳层聚合物覆盖率和壳层聚合物分子量对热驱动线圈到螺旋转变的影响；2)这些粒子作为非常大的单体，将通过磁场使它们垂直于条纹光学模式而聚合成几乎均匀的链，这将引发最初为蛋白质开发的光化学交联反应；3)通过x射线或可见辐射的分离和散射色谱，将更好地了解二氧化硅岩心结构，包括新发现的变体；4)水溶性、不带电多肽的硬度将通过色谱和散射相结合的方法来测定；5)采用光学示踪法探索刚性棒和多肽半柔性丝的迁移率之间的巨大差异；6)使用脉冲梯度核磁共振测量刚性棒扩散的长期问题将使用非常高场梯度的设备重新评估。非技术总结：自然界中一些最重要的构建模块和功能引擎是由蛋白质组成的。人工合成的多肽可以通过简单的方法大量生产，它借用蛋白质的结构并保留了许多类似蛋白质的特征，比如旋转光线和对环境中的热或化学变化做出反应的能力。问题是，尽管多肽是非常大的分子，但它们仍然是非常小的东西。这使得它们很难被操纵。这项工作将生物多肽的功能与利用重力或磁场轻松操纵大颗粒结合在一起。这将通过将多肽放置在胶体二氧化硅（本质上是小玻璃球）上来实现，从而产生核壳颗粒。通过调节温度，多肽壳的形状将被改变。这将提供类似于流感病毒穿透人体的形状转变的信息。由光作用交联的颗粒链将产生几乎均匀的细丝，使聚合物科学进入更容易检查的可见状态，同时促进更大结构的创建。对一种特别有吸引力的水溶性多肽的研究将使人们更好地了解用于制造高强度纤维的聚合物的种类，比如那些编织成防弹背心的聚合物。在社会影响方面，由于成功地吸引了专业教育工作者，在少数民族服务地区，中学化学竞赛将进一步扩大。随后将与一所公共科技中学开展新的推广活动，并将其与现实世界的经验和实验室研究相结合。

NON-TECHNICAL SUMMARY:Some of nature's most important building blocks and functional engines are made of proteins. Synthetic polypeptides, which can be made in large amounts by simple methods, borrow the protein structure and retain many protein-like features, such as the ability to rotate light and respond to thermal or chemical changes in the environment. The problem is that, even though they are very large molecules, polypeptides are still very small things. This makes them hard to manipulate. This project marries the functionality of bio-inspired polypeptides to the easy manipulation of larger particles using gravitational or magnetic fields. This will be accomplished by placing the polypeptides onto colloidal silica, essentially little balls of glass, resulting in core-shell particles. By adjusting the temperature, the shape of the polypeptide shell will be altered. This will provide information on shape transitions similar to those used e.g. by influenza virus to penetrate the human body. Chains of particles crosslinked by the action of light will result in nearly uniform filaments that bring polymer science into the visible regime for easier inspection, while facilitating the creation of even larger structures. Studies on a particularly attractive water-soluble polypeptide will lead to improved understanding of the kinds of polymers used to make high-strength fibers, such as those woven into bullet-proof vests. New educational and outreach initiatives are incorporated, integrated with real-world experience and laboratory research.TECHNICAL SUMMARY: These research activities will develop and explore submicron particles having synthetic polypeptide shells atop silica cores, sometimes with magnetic inclusions. The polypeptide shells render the particles responsive to temperature and good sensors of molecular asymmetry, while the silica cores make it possible to direct these functions to a particular location. Whole particles and their individual polypeptide and silica components will be studied. Specifically, the following work will be performed: 1) The effects of core radius, shell polymer coverage, and shell polymer molecular weight on a thermally driven coil-to-helix transition will be assessed by small-angle X-ray and neutron scattering, static and dynamic light scattering, optical rotatory dispersion, and NMR; 2) The particles, acting as very large monomers, will be polymerized into nearly uniform chains by using a magnetic field to align them perpendicular to a striped optical pattern that will initiate a photochemical crosslinking reaction originally developed for proteins; 3) Better understanding of silica core structure, including newly discovered variants, will be achieved by chromatography with fractionation and scattering of X-ray or visible radiation; 4) The stiffness of a water-soluble, uncharged polypeptide will be determined by combined chromatographic and scattering methods; 5) A big difference between the mobility of rigid rods and polypeptide semiflexible filaments will be explored by an optical tracer method; 6) A long-standing problem with the measurement of rigid rod diffusion using pulsed-gradient NMR will be re-assessed using a very high-field-gradient facility.NON-TECHNICAL SUMMARY:Some of nature's most important building blocks and functional engines are made of proteins. Synthetic polypeptides, which can be made in large amounts by simple methods, borrow the protein structure and retain many protein-like features, such as the ability to rotate light and respond to thermal or chemical changes in the environment. The problem is that, even though they are very large molecules, polypeptides are still very small things. This makes them hard to manipulate. The proposed work marries the functionality of bio-inspired polypeptides to the easy manipulation of larger particles using gravitational or magnetic fields. This will be accomplished by placing the polypeptides onto colloidal silica, essentially little balls of glass, resulting in core-shell particles. By adjusting the temperature, the shape of the polypeptide shell will be altered. This will provide information on shape transitions similar to those used by influenza virus to penetrate the human body. Chains of particles crosslinked by the action of light will result in nearly uniform filaments that bring polymer science into the visible regime for easier inspection, while facilitating the creation of even larger structures. Studies on a particularly attractive water-soluble polypeptide will lead to improved understanding of the kinds of polymers used to make high-strength fibers, such as those woven into bullet-proof vests. In terms of societal impact, a middle school chemistry competition will be further expanded in minority-serving districts, thanks to successful attempts to woo professional educators to this cause. New outreach initiatives with a public science & technology middle school will ensue, integrated with real world experience and laboratory research.