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，长期心血管导管置入在这方面提出了重大的临床挑战。值得注意的是，血栓形成和基于生物膜的感染性植入物感染经常是密不可分的，有效地抵消了治疗的解决，使感染和血栓形成继续不减。许多基于药物和材料的方法解决生物材料相关的血栓形成已经发表。然而，很少有人积极寻求同时解决血栓和感染的组合方法，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：一种重组蛋白基聚合物含有基因编码肝素结合基序的盒子，与MaSp2丝蛋白主干连接，提供了一种“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性能。这种生物材料的构建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，产生一种新的嵌合基生物材料，它能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的进行：1)确定ARKKAAKA的临界密度，该密度在体外基于血浆的测定中提供非血栓形成和抗菌活性；2)确定MaSp2丝基序的临界密度（GGYGPGQQGPGGYGPGQQGPSGPGSAAAAAAAA）n，在血流诱导的剪切应力下提供具有适当机械性能和抗血栓形成性能的血液透析导管表面涂层；3)生产一种双盒生物聚合物材料，结合肝素结合肽（ARKKAAKA）n和MaSp2丝基序（ggygpgqqgpggygpgqqqqgpsgpgsaaaaaaaa）n（其中n在Specific Aims 1和2中确定），在可控的结构中提供机械完整性，血液相容性和微生物耐药性。在本提案的结论中，我们将在血浆、全血或其他生物学相关环境中，使用严格的肝素结合、抗菌和机械完整性分析的组合，生产并验证一种新型蛋白质血液相容、抗菌、机械坚固的血液接触表面涂层的耐久性和活性。

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.