CAREER: High-Density Non-Fouling Bioactive Coatings for Processing of Biological Fluids

细菌性败血症是一种常见且危及生命的疾病，每年仅在美国就导致数十万美国人死亡，造成约200亿美元的损失。败血症目前用抗生素治疗，但这并不能去除循环中的死细菌及其细胞膜碎片（内毒素），这可能会引起严重的免疫反应。减轻这种风险的一种很有希望的方法是让病人的血液通过一种装置来捕获循环中的内毒素，这有助于稳定免疫系统，并有可能改善他们的预后。然而，对于这种应用，所有与血液接触的材料必须具有生物相容性（即抗污染或凝血，并且不会引起不良的生物反应）。对于脓毒症的治疗，表面也必须以控制的方向和高密度呈现内毒素结合剂。这些具有生物活性和生物相容性的涂层必须价格低廉，易于适用于各种材料，包括用于医疗器械、针头、柔性管和其他相关设备的塑料。生物相容性和生物活性涂层可能对败血症治疗的安全性和有效性产生变革性影响，即使是适度的改善也可能导致许多人的生命和节省大量资金。在其他生物医学应用中，该技术还可以将生物活性赋予各种其他家庭、消费者和工业产品。该项目的综合教育活动预计将实现以下好处：(a)研究概念将纳入俄勒冈州立大学（OSU）的生物工程课程，实践学习模块将适用于俄勒冈州立大学面向大学预科学生的STEM学院；(b) PI将与俄勒冈州立大学商学院合作，为该小组的研究生和教师导师提供夏季“创业训练营”。该项目的研究将通过基于表面活性剂的固定化引发剂的活性聚合，在表面产生分支的亲水性聚合物刷，从而开发出高密度、无污染的生物活性涂层（HNB’s）。这种涂层，本质上是一种超薄的固定化水凝胶，将提供出色的抵抗蛋白质吸附和细胞相互作用（生物相容性）。为了在水凝胶表面赋予生物活性，一种近乎理想的生物正交结扎（BOL）将被用于固定刷周围的酶、肽、多糖或其他生物活性分子。这种化学反应可以使活性分子的稀溶液进行定量偶联，从而精确控制表面功能化。未反应的基团具有生物相容性和化学惰性。遗传密码扩展（GCE）提供了多肽或蛋白质的经济固定，其中工程微生物表达在遗传控制位置结合BOL反应基团的活性蛋白。由此产生的仅从粗细胞裂解物中所需蛋白质的特异性固定消除了昂贵的纯化或预浓缩步骤，并保证蛋白质处于精确定义的方向以获得最大的生物活性。虽然这项工作的主要目的是展示用于从血液中捕获病原体的设备的生物相容性和生物活性涂层，但无数其他潜在用途包括更安全的医疗设备，食品加工，药品生产，活性包装和自清洁织物等。

CAREER 1553183 - SchilkeBacterial sepsis is a common and life-threatening condition which kills hundreds of thousands of Americans and costs ~$20 billion every year in the U.S. alone. Sepsis is currently treated with antibiotics, but this does not remove the circulating dead bacteria and fragments of their cell membranes (endotoxin), which could cause a serious immune response. One promising method to mitigate this risk involves passing a patient's blood through a device to capture circulating endotoxin, helping to stabilize the immune system and potentially to improve their prognosis. However for this application, all materials in contact with blood must be biocompatible (i.e. resist fouling or clotting, and not induce an adverse biological response). For treatment of sepsis, surfaces must also present endotoxin-binding agents in controlled orientations and at high density. These bioactive and biocompatible coatings must be inexpensive and easy to apply to a wide range of materials, including plastics used in medical devices, needles, flexible tubing, and other associated equipment. Biocompatible and bioactive coatings could have transformative impact on the safety and efficacy of treatment of sepsis, in which even a modest improvement could result in many lives and much money saved. In other biomedical applications, the technology could also impart biological activity to a variety of other household, consumer and industrial products. The integrated educational activities of this project are expected to achieve the following benefits: (a) research concepts will be incorporated into bioengineering coursework at Oregon State (OSU) and hands-on learning modules will be adapted for OSU's STEM Academy for pre-college students and (b) the PI will work with the OSU business school to provide a summer "Entrepreneurship Boot Camp" for the group's graduate students and faculty mentors.The project's research will result in the development of high-density, non-fouling bioactive coatings (HNB's) by living polymerization from surfactant-based immobilized initiators, producing branched, hydrophilic polymer brushes on the surface. This coating, essentially an ultrathin immobilized hydrogel, will provide excellent resistance against protein adsorption and cell interactions (biocompatibility). To impart bioactivity at the hydrogel surface, a nearly-ideal bioorthogonal ligation (BOL) will be used to immobilize enzymes, peptides, polysaccharides, or other biologically active molecules at the periphery of the brush. This chemistry enables quantitative conjugation from even dilute solutions of the active molecule, allowing precise control of surface functionalization. Unreacted groups are biologically compatible and chemically inert. Economical immobilization of peptides or proteins is provided by Genetic Code Expansion (GCE), in which engineered microbes express active proteins with BOL reactive groups incorporated at genetically-controlled positions. The resulting specific immobilization of only the desired proteins from a crude cell lysate eliminates costly purification or pre-concentration steps, and guarantees that the protein is in a precisely defined orientation for maximal biological activity. Although the main objective of this work is to demonstrate biocompatible and bioactive coatings for devices to capture pathogens from blood, myriad other potential uses include safer medical devices, food processing, pharmaceutical production, active packaging, and self-cleaning fabrics, as examples.