Self-assembling Peptides

拟议研究计划的目标：该研究计划的总体目标是开发多功能、可注射的水凝胶，这些水凝胶对酶的存在具有动态响应，以达到控制治疗分子释放的明确目的。特别感兴趣的是肽、蛋白质和DNA的受控释放。 这一点（RADA）4的基本机制，导致的beneficial形成还没有明确阐明。先前的工作（PNAS，2005，102（24）：8414 8419）已经表明，肽自组装成微米长的纳米纤维，从小球，发生在60秒内;一个时间框架，似乎无视物理解释。关于N-末端氨基酸的添加，我们已经观察到（在制备中）氨基酸化学及其随后的水合状态可以极大地影响该组装过程。既然这两种成分已被确定为对自组装过程至关重要，进一步的工作将集中在阐明改变实际氨基酸化学组成的影响，以了解单个成分对自组装过程的作用。此外，为了将这些系统应用于受控药物递送，我们先前的工作已经表明，N-末端氨基酸可以用于特异性地改变这些高度水合的水凝胶中不同水类型的群体大小：非冷冻结合、冷冻结合、无结合自由。尽管努力理解溶液中对理想化肽结构域的酶活性（Biomaterials，2011，32（5）：1301-1310），但很少或没有进行研究复杂水凝胶结构内的酶活性的工作，其中水的存在以及沃茨的类型和区域粘度可能影响酶的表观活性。这些主题将在本赠款中进一步概述。 新奇和预期的工作领域或领域的意义：预计这项工作将提供一个框架，了解RADA 4纳米纤维的自组装所涉及的物理化学方面，希望提出一种机制，解释这些分子的快速组装。相关的水结构和区域粘度在这些水凝胶应该允许更好地理解的影响，生物化学对酶的流动性和活性。虽然一些工作已经研究了酶的作用作为沃茨的功能，理解这一领域的水凝胶将是至关重要的，以进一步生物物理的理解酶的作用在复杂的介质。

Objectives of the proposed research program: The overall objective of this research program is to develop multifunctional, injectable, hydrogels that are dynamically responsive to the presence of enzymes for the express purpose of controlling the release of therapeutic molecules. Of particular interest is the controlled release of peptides, proteins, and DNA. The fundamental mechanisms leading to nanofiber formation have not been clearly elucidated for this (RADA)4. Previous work (PNAS, 2005, 102(24):8414 8419) has shown that peptide self-assembly into micron long nanofibers, from globules, occurs within 60 seconds; a time frame that seems to defy a physical explanation. With respects to the addition of N-terminal amino acids, we have observed (in preparation) that amino acid chemistry, and their subsequent hydration state, can greatly affect this assembly process. Now that these two components have been identified as being crucial to nanofiber formation, further work will focus on elucidating the effect of altering the actual amino acid chemical makeup to understand the role individual components have on self-assembly process. Furthermore, in order for these systems to be applied for controlled drug delivery, our previous work has shown that N-terminal amino acids can be used to specifically modify the population size of different water types within these highly hydrated hydrogels: non-freezing bound, freezing bound, unbounded free. Despite efforts understanding the enzymatic activity toward idealized peptide domains in solution (Biomaterials, 2011, 32(5): 1301-1310) little to no work has been conducted on investigating enzymatic activity within the complex hydrogel structure, where the presence of the nanofiber, as well as types of waters, and regional viscosity may affect the apparent activity of enzymes. These topics will be further outlined within this grant. Novelty and expected significance of the work to a field or fields: It is expected that this work will provide a framework for understanding the physicochemical aspects involved in the self-assembly of RADA4 nanofibers, hopefully presenting a mechanism that explains the rapid assembly of these molecules. Correlating water structures and regional viscosity in these hydrogels should allow for a better understanding of the effect nanofiber chemistry has on the mobility and activity of enzymes. Although some work has investigated enzyme action as a function of waters, understanding this in the realm of a hydrogel will be crucial to furthering a biophysical understanding of enzyme action in complex media.