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器械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，血栓形成和基于感染性生物膜的植入物感染通常是密不可分的，有效地对抗了治疗方法的消退，使感染和血栓形成持续进行。已经发表了许多基于药物和材料的方法来解决生物材料相关的血栓形成。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，同时提供持久的机械弹性作为生物材料或涂层。这些观察结果构成了我们的总体工作假设：含有用于遗传编码肝素结合基序的盒的基于重组蛋白的聚合物，与MaSp 2丝蛋白骨架连接，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微生物性质。该生物材料构建体将基于已知的重组丝基蛋白表达，结合已知的哺乳动物蛋白的肝素结合模拟，以产生新的基于嵌合体的生物材料，其以高亲和力主动结合循环肝素。将根据以下具体目标进行所提出的医疗器械涂层的制造：1）确定在基于血浆的测定中提供体外非血栓形成和抗微生物活性的ARKKAKA的临界密度; 2)确定MaSp 2丝图案的临界密度，（GGYGPGQQGPGGYGPGQQGPSGPGSAAAAAAAA）n，需要在血流诱导的剪切应力下提供具有适当机械和抗血栓形成性能的血液透析导管表面涂层; 3）产生结合肝素结合肽的基于双盒生物聚合物的材料（ARKKAKA）n和MaSp 2丝绸图案（GGYGPGQQGPGGYGPGQQGPSGSAAAAAAAA）n（其中n在特定目标1和2中确定），以提供机械完整性、血液相容性和微生物抗性。在本提案结束时，我们将在血浆、全血或其他生物相关环境中使用严格的肝素结合、抗菌和机械完整性试验组合，生产并验证新型蛋白质血液相容性、抗菌、机械耐用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。本提案中所述的办法将设法满足这一需要，办法是：（1）具有通用控制和设计特征的新型生物聚合物生物材料，（2）从宿主捕获循环肝素的固有能力，（3）来自可再生肝素化表面的相关血液接触性能益处，（4）使用工业测试标准评估血液透析导管血栓形成和抗微生物特性，和（5）来自当前基于丝的生物材料努力的已知的大规模生产和成本结构。最终，需要将新的生物材料快速转化为商业用途，作为目前医疗器械使用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.