由半化聚合物凝聚的聚合物组装成自组织的囊泡柱,与半化亚努斯 dendrimers 作为反向热驱动器
Virgil Percec1, Mohammad R Imam, Mihai Peterca
1Roy & Diana Vagelos Laboratories, Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, USA. percec@sas.upenn.edu
Journal of the American Chemical Society
|February 7, 2012
概括
研究人员使用雅努斯树状树枝体合成了新型聚合物,创造了独特的膀状柱状结构. 这些聚合物作为反向热执行器,在加热时缩短.
科学领域:
- 聚合物化学 聚合物化学
- 超分子化学 超分子化学
- 材料科学 材料科学 材料科学
背景情况:
- 亚努斯树枝状体,具有明显的功能末端的分子,提供独特的自我组装特性.
- 树突聚合物将树突结构纳入聚合物骨干,影响材料特性.
- 控制凝结聚合物的结构是设计先进的功能材料的关键.
研究的目的:
- 合成和结构性表征聚合物与自我组装的Janus树状树状树.
- 研究自我组装机制和由此产生的超分子结构.
- 为了探索这些新型登德罗化聚合物的热启动行为.
主要方法:
- 雅努斯树枝状体的合成及其附着在聚合物骨干上.
- 使用差分扫描热度计 (DSC) 和X射线衍射 (XRD) 的结构分析.
- 电子密度测绘以阐明超分子组织.
主要成果:
- 成功合成了由化和化两端连接的雅努斯树状聚合物与树状聚合物.
- 观察一个带状柱状结构,周围有化基团.
- 反向热启动的演示:高分子柱长度随着温度的增加而减少.
结论:
- 亚努斯树枝状物使得在树枝状的聚合物中形成独特的囊泡状柱状结构.
- 这些聚合物表现出反向热启动,这是对温度变化的新反应.
- 这些发现为开发具有可调节的热响应性质的新材料开辟了道路.
相关概念视频
Actin Polymerization and Cell Motility
Actin is a family of globular proteins that are highly abundant in eukaryotic cells. It makes up approximately 1-5% of total cell protein concentration. Actin monomers polymerize to form a complex network of polarized filaments, the actin cytoskeleton, that plays a crucial role in many cellular processes, including cell motility, division, endocytosis, and metastasis of cancer cells.
Actin cytoskeleton dynamics can produce pushing, pulling, and resistance forces that help the cell to migrate.
Actin cytoskeleton dynamics can produce pushing, pulling, and resistance forces that help the cell to migrate.
Mechanism of Filopodia Formation
Filopodia are thin, actin-rich cellular protrusions that play an important role in many fundamental cellular functions. They vary in their occurrence, length, and positioning in different cell types, suggesting their diverse roles.
Their main function is to guide migrating cells during normal tissue morphogenesis or cancer metastasis by recognizing and making initial contacts with the extracellular matrix. However, they can also act as stationary cell anchors or help to establish communication...
Their main function is to guide migrating cells during normal tissue morphogenesis or cancer metastasis by recognizing and making initial contacts with the extracellular matrix. However, they can also act as stationary cell anchors or help to establish communication...
Mechanism of Lamellipodia Formation
Cells migrating in response to external stimuli form lamellipodia, which are thin membrane protrusions supported by a mesh of linked, branched, or unbranched actin filaments. These actin filaments interact with myosin motor proteins, creating the dynamic actomyosin complex within the cytoskeleton. Contractility, or the ability to generate contractile stress, is inherent to the actomyosin complex. It helps cells detect the stiffness of the surrounding ECM and exert contractile force for...
Formation of Higher-order Actin Filaments
The polymerization of G-actin monomers into filamentous F-actin is a multi-step process. Once the F-actins are formed, they can bundle together in different arrangements to form higher-order networks and regulate cellular functions. Common examples include the formation of lamellipodia and filopodia at the cell's leading edge by actin reorganization in a migrating cell. The microvilli on the brush border epithelial cells are also formed through the F-actin network.
The high-order actin networks...
The high-order actin networks...
Assembly of Cytoskeletal Filaments
Cytoskeletal filaments are polymeric forms of smaller protein subunits. However, individual cytoskeletal filaments may easily disassemble or associate with other similar filaments to form rigid structures. Microfilaments, made of actin monomers, rely on actin-binding proteins to form bundles and create networks of individual actin filaments. Microtubules rely on microtubule-associated proteins (MAPs) to form sturdy cylindrical structures. However, the proteins involved in forming complex...
The Movement of Organelles and Vesicles
In eukaryotic cells, cytoskeletal filaments such as actin, microtubules, and intermediate filaments form a mesh-like cytoskeletal network. These filaments serve as tracks for transporting cellular cargo. Specialized motor proteins use the chemical energy stored in adenosine triphosphate (ATP) for this transport. During interphase, microtubules are polarized, with the plus-end towards the cell periphery and the minus-end towards the cell center. Two microtubule-associated motor proteins,...


