Biomimetic Approach to the Fabrication of Red Blood Cell Mimics

描述(申请人提供)：尽管有大量投资，但开发和制造血液替代品的尝试多次失败，目前北美或欧洲还没有批准用作血液替代品的产品。在这项应用中，我们建议采用仿生方法来设计红细胞(RBC)，使用由北卡罗来纳大学教堂山分校开发的名为Print TM(非湿润模板中的粒子复制)的强大纳米模塑技术。Print TM将用于合成形状特定、胶体稳定的水凝胶颗粒，其尺寸和机械性能类似于红细胞，并且可以单独变形，使它们能够穿过脾中3微米大小的正弦。以前设计合成血液的方法主要集中在：1)能够溶解大量血液气体的碳氟乳剂；2)聚乙二醇化的血红蛋白；以及3)脂质体输送的血红蛋白。到目前为止，还没有人报道直接模塑RBC模拟物，它具有与RBC相同的进化设计的形状和变形性或弹性。 Print TM成型技术使我们能够独立设计和研究真正替代血液所需的关键标准，包括：形状控制、颗粒模数或弹性、表面化学和表面配体，包括自身标记、流动特征和气体传输特征。模制颗粒能够以货物的形式隔离血红蛋白和变构效应器，防止游离血红蛋白的释放和循环，以促进栩栩如生的携氧能力，但其形式使其与各种器官的物理接触隔离，以避免与游离血红蛋白及其交联物相关的已知副作用。此外，我们还建议将“自我标记”结合到这些可变形的模塑红细胞模拟物上，以最大限度地减少网状内皮系统(RES)的消除。该计划的主要目标将是开发一种长期循环的氧载体，具有氧平衡曲线的经典S型形状，具有与真实红细胞相关的表面积与体积比，以实现最佳的携氧和释放能力，如体外和体内研究所证明的那样。 开发安全有效的合成血液替代品的必要性是显而易见的。据估计，到2030年，仅美国一国就会出现多达400万单位的献血短缺。此外，目前的血液供应增加了疾病传播的风险，包括艾滋病毒、甲型肝炎病毒、B19细小病毒、丙型肝炎病毒和传染性普恩蛋白，这些蛋白与变异的克雅氏病、疯牛病和瘙痒病有关。血液供应的军事用途也很清楚。尤其是不需要血液抗原类型匹配的货架稳定供应。除了血液供应，还需要创新的氧气输送方法来治疗中风、心肌梗死、冠状动脉阻塞、器官移植保存和恶性疾病等疾病，这些疾病每年影响着400多万美国人。

DESCRIPTION (provided by applicant): Despite substantial investment, there are many failed attempts to develop and manufacture a blood substitute and at this time there are no currently approved products for use as blood substitutes in North America or Europe. We propose in this application to take a biomimetic approach to the design of red blood cells (RBC) using a powerful nano-molding technique called PRINT TM (Particle Replication in Non-wetting Templates) developed at the University of North Carolina at Chapel Hill. PRINT TM will be used synthesize shape-specific, colloidally stable, hydrogel particles with dimensions and mechanical properties which resemble red blood cells and that are individually deformable in a manner to allow them to pass through the 3 micron sized sinusoids in the spleen. Previous approaches for the design of synthetic blood have focused on i) fluorocarbon emulsions which can dissolve large amounts of blood gases; ii) PEGylated hemoglobin; and iii) liposomal delivery of hemoglobin. Heretofore, no one has reported direct molding of RBC mimics which have the same evolutionarily designed shapes and deformability or modulus as RBCs. The PRINT TM molding technique allows us to independently design and investigate the key criteria necessary for a true replacement for blood, including: shape control, particle modulus or flexibility, surface chemistry and surface ligands including markers of self, flow characteristics and gas transport characteristics. The molded particles are able to sequester hemoglobin and allosteric effectors as a cargo, preventing the release and circulation of free-hemoglobin, to facilitate life-like oxygen carrying capacity, but have it in a form that isolates it from physical contact with various organs to avoid the documented side effects associated with free hemoglobin and its cross-linked derivatives. In addition, we also propose to conjugate "markers of self" onto these deformable molded RBC mimics to minimize elimination by the reticuloendothelial system (RES). Key goals of the program will be to develop an oxygen carrier that is long circulating and has the classical sigmoidal shape of the oxygen equilibrium curve with a surface to volume ratio associated with a true RBC for optimal oxygen carrying and release capacity as demonstrated by in vitro and in vivo studies. The need to develop safe and effective synthetic blood substitutes is clear. There will be an estimated shortage of as much as 4 million units of donor blood in the United States alone by 2030. In addition, there is increasing risk of disease transmission from current blood supplies including HIV, Hepatitis A virus, B19 parvovirus, Hepatitis C virus, and infectious prion proteins the agents associated with variant Creutzfeldt-Jakob disease, mad cow disease, and scrapie. Military uses of blood supplies are also clear. Especially shelf-stable supplies that don't require blood antigen type matching. Beyond blood supply, there is a significant need for innovative oxygen delivery approaches to treat such conditions as stroke, myocardial infarction, coronary blockage, organ preservation for transplantation, and malignant disease which affect more than 4 million Americans each year.