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Approaches to hybrid synthetic devices.

机译:混合合成设备的方法。

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All living creatures are made up of cells that have the ability to replicate themselves in a repetitive process called cell division. As these cells mature and divide into two there is an extensive movement of cellular components. In order to perform this essential task that sustains life, cells have evolved machines composed of proteins. Biological motors, such as kinesin, transport intracellular cargo and position organelles in eukaryotic cells via unidirectional movement on cytoskeletal tracts called microtubules. Biomolecular motor proteins have the potential to be used as 'nano-engines' for switchable devices, directed self assembly, controlled bioseparations and powering nano- and microelectromechanical systems. However, engineering such systems requires fabrication processes that are compatible with biological materials such as kinesin motor proteins and microtubules. The first objective of the research was to establish biocompatibility between protein systems and nanofabrication. The second objective was to use current micro- and nanofabrication techniques for patterning proteins at specific locations and to study role of casein in supporting the operation of surface bound kinesin. The third objective was to link kinesin and microtubule system to cellulose nanowhiskers.;The effects of micro- and nanofabrication processing chemicals and resists on the functionality of casein, kinesin, and microtubule proteins are systematically examined to address the important missing link of the biocompatibility of micro- and nanofabrication processes needed to realize hybrid system fabrication. It was found that both casein, which is used to prevent motor denaturation on surfaces, and kinesin motors are surprisingly tolerant of most of the processing chemicals examined. Microtubules, however, are much more sensitive. Exposure to the processing chemicals leads to depolymerization, which is partially attributed to the pH of the solutions examined. When the chemicals were diluted in aqueous buffers, a subset of them no longer depolymerized microtubules and in their diluted forms still worked as resist removers.;Electron beam nanolithography process was used for patterning kinesin motor proteins on glass. This process was then used to fabricate discontinuous kinesin tracks to study the directionality of microtubule movement under the exclusive influence of surface bound patterned kinesin. To study casein and kinesin interactions, a series of microtubule motility assays were performed where whole milk casein, or its alphas1 and alphas2, ss or kappa subunits, were introduced or omitted at various steps of the motility assay. In addition, a series of epifluorescence and total internal reflection microscopy (TIRF) experiments were conducted where fluorescently labeled casein was introduced at various steps of the motility assay to assess casein-casein and casein-glass binding dynamics. From these experiments it is concluded that casein forms a bi-layer which supports the operation of kinesin. The first tightly bound layer of casein mainly performs the function of anchoring the kinesin while the second more loosely bound layer of casein positions the head domain of the kinesin to more optimally interact with microtubules. Studies on individual casein subunits indicate that ss casein is most effective in supporting kinesin functionality while kappa casein is the least effective.;Kinesin and microtubules self assemble in vitro to form asters that are envisioned to be linked to cellulose fibers. This can be used for creating percolated reinforcing structures that can be used to fabricate composites with reduced fiber content. Technological advances are required to create cellulose orientation during papermaking to reduce the content of fiber while maintaining the paper quality. Microtubule aster assembly can be used as a template to create and study the mechanical properties of percolated cellulose nanowhisker systems. Reducing the fiber content to half will save around 2 billion trees from being used for paper making. We successfully hydrolyzed cotton cellulose using concentrated sulfuric acid and analyzed it by scanning electron microscopy. The whiskers obtained were 400 nm to few micrometers long. Cellulose whiskers were successfully biotinylated and linked to biotinylated microtubules. This study lays down a method to align cellulose nanowhiskers using self assembly of microtubules to create highly percolated cellulose structures using lesser cellulose fiber content.
机译:所有活物都是由细胞组成的,这些细胞具有在称为细胞分裂的重复过程中自我复制的能力。随着这些细胞的成熟并分为两部分,细胞成分的广泛运动。为了执行维持生命的这一重要任务,细胞已经进化出由蛋白质组成的机器。生物动力,例如驱动蛋白,通过在称为微管的细胞骨架上的单向运动在真核细胞中运输细胞内货物和定位细胞器。生物分子运动蛋白有潜力用作可切换设备,定向自组装,受控的生物分离以及为纳米和微机电系统提供动力的“纳米引擎”。但是,对此类系统进行工程设计需要与生物材料(例如驱动蛋白运动蛋白和微管)兼容的制造工艺。该研究的首要目标是建立蛋白质系统与纳米加工之间的生物相容性。第二个目标是使用当前的微细加工和纳米加工技术在特定位置构图蛋白质,并研究酪蛋白在支持表面结合驱动蛋白的作用中的作用。第三个目标是将驱动蛋白和微管系统与纤维素纳米晶须联系起来;系统地研究了微和纳米加工化学品和抗蚀剂对酪蛋白,驱动蛋白和微管蛋白功能的影响,从而解决了生物相容性的重要缺失环节。实现混合系统制造所需的微型和纳米制造工艺。已经发现,用于防止表面上的马达变性的酪蛋白和驱动蛋白马达都令人惊奇地耐受大多数所检查的加工化学品。然而,微管更为敏感。暴露于加工化学品会导致解聚,这部分归因于所检查溶液的pH值。当化学品在水性缓冲液中稀释时,其中的一部分不再解聚,并且仍以稀释形式用作抗蚀剂去除剂。;电子束纳米光刻工艺用于在玻璃上对驱动蛋白运动蛋白进行构图。然后,该过程用于制造不连续的驱动蛋白轨迹,以研究在表面结合的图案驱动蛋白的排他性影响下微管运动的方向性。为了研究酪蛋白和驱动蛋白的相互作用,进行了一系列微管运动测定,其中在运动测定的各个步骤中引入或省略了全脂酪蛋白或其αs1和alphas2,ss或kappa亚基。此外,进行了一系列的落射荧光和全内反射显微镜(TIRF)实验,其中在运动分析的各个步骤引入了荧光标记的酪蛋白,以评估酪蛋白-酪蛋白和酪蛋白-玻璃结合动力学。从这些实验可以得出结论,酪蛋白形成支持驱动蛋白操作的双层。酪蛋白的第一紧密结合层主要执行锚定驱动蛋白的功能,而酪蛋白的第二较松散结合的层定位驱动蛋白的头部结构域,使其与微管更理想地相互作用。对单个酪蛋白亚基的研究表明,ss酪蛋白在支持驱动蛋白功能方面最有效,而kappa酪蛋白效果最差。;激肽和微管在体外自我组装,形成可与纤维素纤维连接的翠菊。这可用于产生渗滤增强结构,该渗滤增强结构可用于制造纤维含量降低的复合材料。需要技术进步以在造纸过程中产生纤维素取向,以减少纤维含量,同时保持纸质。微管紫assembly装配可以用作创建和研究渗滤纤维素纳米晶须系统机械性能的模板。将纤维含量减少一半将节省约20亿棵用于造纸的树木。我们使用浓硫酸成功地水解了棉纤维素,并通过扫描电子显微镜对其进行了分析。获得的晶须为400nm至几微米长。纤维素晶须被成功地生物素化并链接到生物素化的微管。这项研究提出了一种利用微管的自组装来对齐纤维素纳米晶须的方法,该方法可使用较少的纤维素纤维含量创建高度渗透的纤维素结构。

著录项

  • 作者

    Verma, Vivek.;

  • 作者单位

    The Pennsylvania State University.;

  • 授予单位 The Pennsylvania State University.;
  • 学科 Chemistry Polymer.;Biophysics General.;Engineering Materials Science.
  • 学位 Ph.D.
  • 年度 2009
  • 页码 200 p.
  • 总页数 200
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 高分子化学(高聚物);工程材料学;生物物理学;
  • 关键词

  • 入库时间 2022-08-17 11:37:38

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