Hybrid Silica-Polypeptide Particles: Properties, Transitions and Superstructures

技术支持： 将开发亚微米混合粒子。每个颗粒将具有二氧化硅核和共价连接的多肽壳。壳赋予了有趣的化学性质;它可以被定制为响应温度，即使在没有强大离子力的有机溶剂中，或者在这些力占主导地位的水性环境中的pH值。将控制颗粒的尺寸、表面密度和表面厚度，从而能够研究这些参数如何影响构象转变。将探索通过"附着"机制（完全形成的聚合物连接到二氧化硅核）制造颗粒的限制。这些粒子具有许多有用的物理功能。核或壳可以带有荧光部分，以促进磁性排列、平衡结构或相分离的可视化。包含壳的多肽在不与核连接时能够形成液晶，从而提高了在被这些分子覆盖的颗粒接触的地方形成"局部液晶"的可能性，从而提高了介晶的局部浓度。这将通过使用施加的磁场将粒子的超顺磁性变体链接在一起来探索。当保持在这些链中时，将探索颗粒或其前体核心上的反应，可能导致颗粒穿着多肽带或聚（胶体），其可能能够经历肌肉样的膨胀和收缩，甚至在有机溶剂中。非技术性： 多肽包被的颗粒为应用发现提供了一个很好的平台，因为它们融合了蛋白质的化学多功能性，识别疾病标志物的能力，可切换的大小和形状，易于使用重力或磁场进行操作。这些颗粒看起来有点像豪猪，中央核心上覆盖着“刺”。人们希望用磁性内含物构建的变体可以连接起来，从而产生对酸度或温度等刺激做出反应的人工“纤毛”。预计未来相关材料将具有光电用途，例如光捕获或与疾病相关的氨基酸传感。与项目团队相关的研究人员将接受长期职业培训，强调技术技能，批判性思维，道德意识和沟通。团队成员应该是他们的手艺和一般科学的事实倡导者。这种表达的一个重要场所将是化学教育基金会的"你是化学家挑战赛"，这是一个面向中学生的"测验弓"。研究生和博士后团队成员将协助学生的竞争和/或培训。在竞赛中表现出色的青年学者将积极参加拟议的研究，消除结构化问答竞赛的主要缺陷，即它不提供实际培训。化学教育基金会试图跟踪其年轻挑战者的职业生涯，这为NSF提供了一种免费跟踪基于竞争的科学培训效果的方法。希望更多的中学生能够以技术爱好为起点，积极参与学习。

TECHNICAL: Submicron hybrid particles will be developed. Each particle will have a silica core and covalently attached polypeptide shell. The shell confers the interesting chemical properties; it can be tailored to respond to temperature, even in an organic solvent where powerful ionic forces are absent, or to pH in aqueous environments where those forces predominate. The size, surface density and surface thickness of the particles will be controlled, enabling a study of how these parameters affect conformational transitions. The limits of making the particles by an "attach to" mechanism (fully formed polymers are connected to the silica cores) will be explored. The particles feature a number of useful physical functions. Either core or shell may bear fluorescent moieties to facilitate visualization of magnetic alignment, equilibrium structures or phase separation. The polypeptides comprising the shell are capable of forming liquid crystals when not tethered to a core, raising the possibility that "local liquid crystals" will form where particles covered with these molecules touch, elevating the local concentration of mesogens. This will be explored by chaining together superparamagnetic variants of the particles using an applied magnetic field. While held in these chains, reactions on the particles or their precursor cores will be explored, possibly leading to particles wearing a polypeptide belt or to poly(colloids) that may be able to undergo muscle-like expansions and contractions, even in an organic solvent. NON-TECHNICAL: Polypeptide-coated particles provide an excellent platform for applied discovery because they merge the characteristics of proteins' chemical versatility, ability to recognize markers for disease, switchable size and shape with ease of manipulation using gravitational or magnetic fields. The particles look a bit like porcupines, with "prickles" coating a central core. It is hoped that variants built with magnetic inclusions can be connected, leading to artificial "cilia" that respond to stimuli such as acidity or temperature. Related materials in the future are anticipated to have optoelectronic uses, such as light harvesting or sensing of amino acids related to disease. Researchers associated with the project team will train for a long career, emphasizing technical skills, critical thinking, ethical awareness and communication. Team members are expected to be factual advocates for their craft and for science in general. An important venue for such expression will be the Chemical Education Foundation's You Be the Chemist Challenge competition, a "quiz bow" for middle school students. Graduate student and postdoctoral team members will assist with the competition and/or training of students. Selected young scholars who perform well in the competition will actively participate in the proposed research, erasing the major deficiency of a structured question-and-answer competition, i.e. that it provides no practical training. The Chemical Education Foundation attempts to follow the careers of its young challengers, which provides at no cost to NSF a way to track the efficacy of competition-based science training. It is hoped that additional middle school students will be engaged in active learning, using a technical hobby as a starting point.