A Novel Self-Renewing Heparin-Binding Anti-microbial Device Surface Coating

描述（由申请人提供）：血栓形成和感染仍然是任何血液接触医疗设备的性能和寿命的长期主要挑战。在血液透析和血管通路的背景下，长期心血管导管插入术在这方面提出了重大的临床挑战。值得注意的是，血栓形成和基于传染性生物膜的植入物感染常常有着千丝万缕的联系，有效地对抗治疗的解决，使感染和血栓形成有增无减。许多解决生物材料相关血栓形成的基于药物和材料的方法已经发表。然而很少有人积极寻求组合方法来同时解决血栓形成和感染，同时提供作为生物材料或涂层的持久机械弹性。这些观察结果构成了我们的总体工作假设：基于重组蛋白的聚合物含有基因编码肝素结合基序的盒，与MaSp2丝蛋白主链连接，提供了“自我更新”的富含肝素的聚合物材料，在表面涂层中产生血液相容性和抗菌特性。这种生物材料构建体将基于已知的重组丝蛋白表达，与已知的哺乳动物蛋白的肝素结合模拟相结合，产生一种新的基于嵌合体的生物材料，该生物材料能够以高亲和力主动结合循环肝素。拟议的医疗器械涂层的制造将根据以下具体目标进行：1）确定 ARKKAAKA 的临界密度，该临界密度在基于血浆的测定中提供体外非血栓形成和抗菌活性。 2) 确定MaSp2丝基序的临界密度，(GGYGPGQQGPGGYGPGQQGPSGPGSAAAAAAAA)n，需要在血流引起的剪切应力下提供具有适当机械和抗血栓形成特性的血液透析导管表面涂层； 3) 生产基于双盒生物聚合物的材料，将肝素结合肽 (ARKKAAKA)n 和 MaSp2 丝基序 (GGYGPGQQGPGGYGPGQQGPSGPGSAAAAAAAA)n （其中 n 在特定目标 1 和 2 中确定）结合在受控架构中，以提供机械完整性、血液相容性和微生物耐受性。在该提案结束时，我们将在血浆、全血或其他生物相关环境中结合严格的肝素结合、抗菌和机械完整性测定，生产并验证一种新型蛋白质血液相容性、抗菌性、机械坚固的血液接触表面涂层的耐久性和活性。 公共卫生相关性：血液接触和血液透析导管性能的改善将使数百万患者受益。本提案中描述的方法将寻求通过生产以下产品来满足这一需求：（1）具有多功能控制和设计功能的新型生物聚合物生物材料，（2）从宿主捕获循环肝素的内在能力，（3）可再生肝素化表面的相关血液接触性能优势，（4）使用行业测试标准评估血液透析导管血栓形成和抗菌特性，以及（5）当前丝基生物材料工作中已知的大规模生产和成本结构。最终，希望将新型生物材料快速转化为商业用途，作为目前医疗器械中肝素化涂层阵列的替代品。

DESCRIPTION (provided by applicant): Thrombosis and infection remain long-standing major challenges to the performance and longevity of any blood-contacting medical device. Long-term cardiovascular catheterization, as in the context of hemodialysis and vascular access, presents a significant clinical challenge in this regard. Significantly, thrombus formation and infectious biofilm-based implant infection are frequently inextricably connected, effectively countering resolution with therapeutics, allowing infections and thrombosis to proceed unabated. Many pharmaceutical and materials-based methods addressing biomaterial-associated thrombogenesis have been published. Yet few actively seek combinatorial approaches to address both thrombosis and infection simultaneously while concurrently providing durable mechanical resilience as a biomaterial or coating. These observations frame our overall working hypothesis: a recombinant protein-based polymer containing a cassette for genetically encoding heparin-binding motifs, concatenated with a MaSp2 silk protein backbone, provides a "self- renewing" heparin-enriched polymer material, yielding both hemocompatibility and antimicrobial properties in a surface coating. This biomaterial construct will be based on known recombinant silk-based protein expression, combined with known heparin-binding mimicry for mammalian proteins to yield a new chimera-based biomaterial that actively binds circulating heparin with high affinity. Fabrication of the proposed medical device coating will proceed according to the following specific aims: 1) Determine the critical density of ARKKAAKA that provides both non-thrombogenic and antimicrobial activity in vitro in plasma-based assays.; 2) Determine the critical density of the MaSp2 silk motif, (GGYGPGQQGPGGYGPGQQGPSGPGSAAAAAAAA)n, required to provide a hemodialysis catheter surface coating with appropriate mechanical and antithrombogenic properties under blood flow-induced shear stress; 3) Produce a dual cassette biopolymer-based material combining the heparin-binding peptide (ARKKAAKA)n and the MaSp2 silk motif (GGYGPGQQGPGGYGPGQQGPSGPGSAAAAAAAA)n (where n is determined in Specific Aims 1 and 2), in controlled architectures to provide mechanical integrity, hemocompatibility, and microbial resistance. At the conclusion of this proposal, we will have produced and verified the durability and activity of a novel proteinaceous hemocompatible, antimicrobial, mechanically robust blood-contacting surface coating using a combination of rigorous heparin-binding, antimicrobial, and mechanical integrity assays in either plasma, whole blood or another biologically relevant milieu. PUBLIC HEALTH RELEVANCE: Improved performance for blood-contacting and hemodialysis catheters will benefit millions of patients. The approach described in this proposal will seek to address this need by producing: (1) a new biopolymer biomaterial with versatile control and design features, (2) an intrinsic capability to capture circulating heparins from the host, (3) associated blood-contacting performance benefits from renewable heparinized surfaces, (4) assessment of hemodialysis catheter thrombogenic and antimicrobial properties using industry test standards, and (5) known mass production and cost structures from current silk-based biomaterials efforts. Eventually, rapid translation of the new biomaterial to commercial use as an alternative to the array of heparinized coatings in medical device use currently is desired.