Novel Polyisobutylene-Based Materials and Surfaces; Enzyme-Catalyzed Functionalization and ?Modular? Surface Construction

技术概述：该奖项由材料研究部和国际科学与工程办公室共同资助，旨在合成和表征基于聚异丁烯（PIB）的新型自组装纳米结构热塑性弹性体（TPE）生物材料。具体来说，将继续努力合成新的“熵驱动”tpe （ENTPE）。在目前NSF的支持下，研究人员发现，即使在极短的塑性和弹性体端块中，ENTPEs的树枝状（乔木状或树状）arbPIB中间块也有利于相分离和TPE行为。这些新型的ENTPE材料进一步用纳米级填料（碳和二氧化硅）增强，得到了强橡胶纳米复合材料（ENTPEC），并在兔体内和体外验证了它们的生物相容性。基于这一发现，新的entpe将被合成为具有氢键能力的短端块（例如多肽）。将这些材料与纳米填充剂复合将产生新的ENTPEC纳米复合材料。为了控制表面化学和图案以改善组织整合，提出了一种使用ElectroNanoSprayingTM的新的“模块化”方法，该方法允许构建具有各种化学和拓扑结构的梯度表面。将ENTPE喷涂到ENTPEC表面将产生具有相同化学性质的可控纳米图案。表面化学将通过喷洒低分子量功能化PIBs （PIB-F）来控制，其中F是一种生物活性化合物（核酸碱基，肽，蛋白质等）到ENTPECs表面。pib - f将由PIB-OH精确合成，通过活碳阳离子聚合得到，并使用一种新型酶催化酯交换过程进行功能化，该过程在温和条件下产生完全转化，这也是当前拨款的一部分。“模块化”方法将提供前所未有的对表面化学和表面图案的独立控制，并将有助于对表面特性对高分子材料生物相容性影响的新的基本理解。摘要：本项目旨在合成和表征基于聚异丁烯（PIB）的新型生物材料。这些材料像硅橡胶一样柔软透明，但不需要任何化学处理就能自组装成一个网络，而这是制造硅橡胶所必需的。2004年，一种基于pib的材料被fda批准用作药物洗脱冠状动脉支架的涂层。超过100万个这样的支架被植入病人体内，挽救了生命。所提出的新材料将具有改进的综合性能。此外，本项目还将测试一种新的表面改性方法来提高生物相容性。为了实现这一目标，新的聚合物将通过“绿色聚合物化学”合成，使用酶作为催化剂，并喷涂到新型生物材料的表面。这种新的“模块化”方法将对表面化学和图案进行独立控制，为这些特性对生物相容性的影响提供前所未有的见解。这种新材料可能在某些应用中取代硅橡胶（例如，作为需要防渗性的乳房植入物的外壳）。这个项目是跨学科的，建立在合作者（Nanocopoeia Inc.）的基础上。明尼苏达州、阿克伦生物医学研究协会、华盛顿大学、波兰波美拉尼亚医学院、法国波尔多大学)。它是对德国研究基金会（DFG）最近批准的赠款以及波兰科学和教育部批准的赠款的补充，用于测试新生物材料的各种特性。该基金将支持1名部分女性博士后（Nanocopoeia的NSF资助将补充全职），4名博士生（3名美国人-其中2名女性，1名西班牙裔），未来的REU（本科生研究经验）学生，RET（教师研究经验）和高中生。它还将直接支持国际学生交流和项目会议，间接支持国际学生。该项目将使学生接触到各种科学学科（聚合物化学、有机化学、材料科学、生物化学、表面科学、聚合物工程、生物医学工程、蛋白质组学等）。他们还将有机会在德国、波兰和爱尔兰进行部分研究。接触不同的文化、组织和职业道德将使学生在全球经济中更好地工作，使他们对潜在雇主更具吸引力。我们还将与阿克伦大学（University of Akron）迈尔斯艺术学院（Myers School of art）合作，开展一个将科学与艺术联系起来的新项目，为这两个学科的学生拓宽视野。

TECHNICAL SUMMARY:This award, co-funded by the Division of Materials Research and the Office of International Science and Engineering, aims at the synthesis and characterization of novel self-assembling nanostructured thermoplastic elastomeric (TPE) biomaterials based on polyisobutylene (PIB). Specifically, efforts to synthesize new "Entropy-driven" TPEs (ENTPE) will continue. Under the current NSF support it was discovered that the dendritic (arborescent or tree-like) arbPIB midblock of ENTPEs facilitates phase separation and TPE behavior even with very short plastic and elastomeric end blocks. These novel ENTPE materials were further reinforced with nano-size fillers (carbon and silica) to yield strong rubbery nanocomposites (ENTPEC), and their biocompatibility was demonstrated in vitro and in vivo in rabbits. Based on this discovery, new ENTPEs will be synthesized with short end blocks, capable of hydrogen bonding (e.g., polypeptides). Compounding these materials with nanofillers will yield new ENTPEC nanocomposites. In order to control surface chemistry and patterning for improved tissue integration, a new "modular" approach using ElectroNanoSprayingTM is proposed, which allows the construction of gradient surfaces with various chemistries and topologies. Spraying ENTPE onto the surface of ENTPEC will yield well-controlled nanopatterns of the same chemistry. Surface chemistry will be controlled by spraying low molecular weight (MW) functionalized PIBs (PIB-F) where F is a biologically active compound (nucleic acid base, peptide, protein, etc.) onto the surface of ENTPECs. The PIB-Fs will be precision synthesized from PIB-OH made by living carbocationic polymerization and functionalized using a novel enzyme-catalyzed transesterification process that yields complete conversion under mild conditions this also emerged from the current grant. The "modular" approach will give unprecedented control over surface chemistry and surface patterning independently, and will contribute to new fundamental understanding of the effects of surface properties on the biocompatibility of polymeric materials. NON-TECHNICAL SUMMARY:This project is aimed at the synthesis and characterization of novel biomaterials based on polyisobutylene (PIB). These materials are soft and transparent like silicone rubber, but self-assemble into a network without any chemical treatment which is necessary to make silicone rubber. In 2004, one PIB-based material was FDA-approved as the coating on drug-eluting coronary stents. More than a million of those stents have been implanted into patients, saving lives. The proposed new materials will have improved combination of properties. In addition, a new approach to surface modification to improve biocompatibility will be tested in this project. For this goal new polymers will be synthesized via "green polymer chemistry" using enzymes as catalysts, and sprayed to the surface of the novel biomaterials. This new "modular" approach will give independent control over surface chemistry and patterning, providing unprecedented insight into the effect of these properties on biocompatibility. The new materials may replace silicone rubber in certain applications (for example, as the shell of breast implants where impermeability is required). This project is interdisciplinary, building on collaborators (Nanocopoeia Inc. Minnesota, BioMedical Research Associates Akron, the University of Washington, Pomeranian Medical Academy of Poland, University of Bordeaux, France). It is complementary to a recently approved grant by German Research Foundation (DFG) as well as the grant approved by the Polish Ministry of Science and Education, to test various properties of the new biomaterials. The grant will support 1 partial female Post-doctoral fellow (Nanocopoeia's NSF grant will complement this to full time), four Ph. D. students (3 Americans - two of them females, one Hispanic), future REU (Research Experience for Undergraduates) students, an RET (Research Experience for Teachers), and high school students. It will also support international student exchanges and project meetings directly, and international students indirectly. The project will expose students to a great variety of scientific disciplines (polymer chemistry, organic chemistry, material science, biochemistry, surface science, polymer engineering, biomedical engineering, proteomics etc.). They will also have a chance to carry out part of their research in Germany, Poland and Ireland. Exposure to different cultures, organizations and work ethics will prepare the students to work better in the global economy, making them more attractive to potential employers. We will also embark on a new program connecting science and art, in collaboration with the Myers School of Art at the University of Akron to broaden the horizon for students of both disciplines.