Reducing wound bioburden and biofilm formation using a nanoscale wound surface en

使用纳米级伤口表面减少伤口生物负载和生物膜形成

• 批准号: 8386272
• 负责人: CHARLES Joseph CZUPRYNSKI
• 金额: $ 18.81万
• 依托单位: UNIVERSITY OF WISCONSIN-MADISON
• 依托单位国家: 美国
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-08-01 至 2014-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8386272
• 关键词: Address; Adsorption; Adverse effects; Age; Amino Acids; Anti-Bacterial Agents; Bacillus subtilis; Back; Bacteria; Beds; Caring; Chronic; Data; Debridement; Defense Mechanisms; Effectiveness; Elderly; Engineering; Film; Goals; Healed; Health; Health Care Costs; Healthcare; Host Defense; Human; Immobilization; Impaired wound healing; In Vitro; Incidence; Infection; Intervention; Investigation; Leucine; Mediating; Medical; Methionine; Methods; Microbial Antibiotic Resistance; Microbial Biofilms; Modeling; Organism; Population; Prevention; Procedures; Productivity; Pseudomonas aeruginosa; Quality of life; Reporting; Research Personnel; Research Project Grants; Research Support; Resistance; Sepsis; Silver; Skin; Solutions; Staphylococcus aureus; Structure; Surface; Testing; Therapeutic; Thick; Tryptophan; Tyrosine; United States; United States National Institutes of Health; Wound Infection; antimicrobial; antimicrobial drug; arm; base; cost; cytotoxicity; enantiomer; healing; imprint; improved; in vivo; innovation; killings; microbial; microbial colonization; nano; nanoparticle; nanoparticulate; nanoscale; nanostructured; novel; novel strategies; open wound; prevent; socioeconomics; wound

DESCRIPTION (provided by applicant): Management of chronic wounds represent a major healthcare challenge responsible for over $15 billion in expenses annually. Wound surface sepsis, in particular biofilm formation, is a significant factor in nonhealing wounds. In chronic wounds, >60% have been observed to have clear evidence of a biofilm. Further, NIH has estimated that 65-80% of microbial infections in humans are biofilm-mediated. Biofilms are characterized by resistance to host defenses and to therapeutics that would otherwise have efficacy against the organisms planktonic state. Thus, biofilms present two distinct challenges: 1) the biofilm must be removed or dispersed to reduce bacterial defense mechanisms; and 2) effective antimicrobial agents applied to suppress the resident bacteria. In this application, we seek to address this problem by investigating a novel intervention with potential to prevent chronic colonization of wounds and disperse pre-existing biofilms. The innovation underlying our approach revolves around engineering the surfaces of wound beds to both promote the dissolution of biofilm bacteria back to a planktonic state, where they are more susceptible to antimicrobial agents, and immobilize antimicrobial agents at the wound surface where biofilm formation occurs. Our approach involves incorporation of absorbable nanobeads loaded with antibiofilm agents in a nanoscopic thin film, manufactured of polyelectrolyte multilayers containing silver nanoparticles, that is used to re-engineer the wound surface to increase its resistance to microbial colonization and biofilm formation. This structured engineered approach allows effective antimicrobial action with very low non-toxic concentrations of active agents. The innovative combination of these approaches in a single nanostructured film has the potential to markedly increase anti-biofilm and antimicrobial efficacy in vivo. In particular, use of nano-beads permits precise control over concentrations and release rates of the antibiofilm agent. They also penetrate and create microdomains within the biofilm, increasing surface contact by >80%, to increase adsorption of antibiofilm and antimicrobial agents concurrently and generating progressive dispersion-kill zones emanating from the beads at a nanoscale level. The central hypothesis of this study, supported by exciting preliminary data, is that incorporating select D- and L- amino acids into the wound bed will reduce bacterial biofilm formation and increase biofilm dissolution. A secondary hypothesis is that this approach will enhance the antimicrobial activity of silver nanoparticles immobilized at the wound surface. To address these goals we propose 3 Aims. In Aim 1, we will evaluate the ability of select D- and L- amino acids immobilized in polyelectrolyte thin films and loaded into absorbable PLGA beads to prevent a biofilm from forming and to stimulate dissolution of existing biofilms of Pseudomonas aeruginosa and Staphylococcus aureus in vitro . In Aim 2, we will optimize the integration of select amino acids and nano-beads onto model wound surfaces (full and partial thickness skin wounds), using polyelectrolyte thin film immobilization methods, and evaluate their efficacy in preventing biofilm formation and biofilm dissolution in vivo; and in Aim 3, we will test the hypothesis that combined application of silver nanoparticles and select amino acids further reduces biofilm formation and minimizes microbial bioburden in wounds in vivo. At the conclusion of this study, we expect to provide proof of concept that a two-armed approach to wound biofilms contained in an integrated nanoscale wound bed engineering platform will have increased efficacy against biofilms with reduced cytotoxicity in the wound bed. This approach is labile and generalizable to immobilization of other antibiofilm and antimicrobial agents. Thus, upon successful completion of this R21 application, we will seek support for research (via the R01 mechanism) that will broaden the scope of these investigations in optimizing these strategies and in evaluating the efficacy of an array of antimicrobial and antibiofilm agents with the goal of maximizing the ability to suppress wound bed sepsis and improve healing of chronic open wounds. PUBLIC HEALTH RELEVANCE: This application seeks support for an exploratory investigation of a conceptually novel approach to suppression of wound microbial bioburden and biofilm formation. Simple amino acids have been shown to be effective in preventing biofilms from forming and in promoting biofilm dissolution. These compounds, when integrated into a nanostructured wound surface engineering platform, offer a two-armed approach to dissolution of biofilms and killing of resident bacteria by their combination with a non-antibiotic antimicrobil such as silver in nanoparticulate form. The engineered immobilization platform allows use of low non-toxic concentrations of active agents. Such an approach provides a highly innovative attack of a major health problem without the side effects of cytotoxicity or microbial antibiotic resistance inherent to current conventional wound treatments. We seek to test this hypothesis using a wound engineering approach involving polyelectrolyte multilayers with absorbable nanobeads to deliver both antibiofilm and antimicrobial agents together at the wound surface. Approaches such as this that facilitate prevention of wound sepsis that do not impair wound healing would represent a major healthcare advance.

描述（由申请人提供）：慢性伤口的管理是一项重大的医疗保健挑战，每年的费用超过150亿美元。伤口表面脓毒症，特别是生物膜形成，是不愈合伤口的重要因素。在慢性伤口中，已观察到> 60%具有生物膜的明确证据。此外，NIH估计，人类中65 - 80%的微生物感染是生物膜介导的。生物膜的特征在于对宿主防御和治疗剂的抗性，否则这些治疗剂将对生物体的强直状态具有功效。因此，生物膜提出了两个不同的挑战：1）必须去除或分散生物膜以减少细菌防御机制;和2）应用有效的抗微生物剂以抑制常驻细菌。在本申请中，我们试图通过研究一种新的干预措施来解决这个问题，这种干预措施有可能防止伤口的慢性定植并分散预先存在的生物膜。我们的方法的创新围绕着设计伤口床的表面，以促进生物膜细菌的溶解恢复到对抗微生物剂更敏感的无菌状态，并在发生生物膜形成的伤口表面抑制抗微生物剂。我们的方法涉及将负载有生物膜试剂的可吸收纳米珠并入纳米级薄膜中，该薄膜由含有银纳米颗粒的多层生物膜制成，用于重新设计伤口表面以增加其对微生物定植和生物膜形成的抵抗力。这种结构化的工程方法允许有效的抗菌作用，活性剂的无毒浓度非常低。这些方法在单个纳米结构膜中的创新组合具有显着增加体内抗生物膜和抗微生物功效的潜力。特别地，使用纳米珠粒 允许精确控制涂膜剂的浓度和释放速率。它们还渗透并在生物膜内产生微区，使表面接触增加> 80%，以同时增加生物膜和抗微生物剂的吸附，并产生从纳米级水平的珠粒发出的渐进的分散-杀灭区。由令人兴奋的初步数据支持的本研究的中心假设是，将选择的D-和L-氨基酸掺入伤口床中将减少细菌生物膜形成并增加生物膜溶解。第二个假设是，这种方法将增强固定在伤口表面的银纳米颗粒的抗微生物活性。为了实现这些目标，我们提出了三个目标。在目的1中，我们将评估固定在可吸收薄膜中并加载到可吸收PLGA珠粒中的所选D-和L-氨基酸在体外防止生物膜形成并刺激铜绿假单胞菌和金黄色葡萄球菌的现有生物膜溶解的能力。在目标2中，我们将优化选择的氨基酸和纳米珠在模型伤口表面上的整合（全层和部分厚度皮肤伤口），并评价它们在体内防止生物膜形成和生物膜溶解的功效;在目标3中，我们将检验以下假设，即银纳米颗粒和选择的氨基酸的组合应用进一步减少生物膜的形成并使微生物生物负荷最小化，体内伤口。在本研究的结论中，我们期望提供概念证明，即集成纳米级伤口床工程平台中包含的伤口生物膜的双臂方法将提高对生物膜的功效，同时降低伤口床中的细胞毒性。这种方法是不稳定的，并可推广到其他生物膜和抗菌剂的固定。因此，在成功完成R21申请后，我们将寻求研究支持（通过R01机制），以扩大这些研究的范围，优化这些策略，并评估一系列抗菌剂和抗菌膜剂的有效性，以最大限度地抑制伤口床脓毒症并改善慢性开放性伤口的愈合。 公共卫生相关性：本申请寻求对抑制伤口微生物生物负载和生物膜形成的概念性新方法的探索性研究的支持。简单氨基酸已被证明在防止生物膜形成和促进生物膜溶解方面是有效的。这些化合物，当整合到纳米结构伤口表面工程平台中时，通过与非抗生素抗微生物剂如纳米颗粒形式的银组合，提供了溶解生物膜和杀死常驻细菌的双臂方法。工程化固定平台允许使用低无毒浓度的活性剂。这种方法提供了对主要健康问题的高度创新的攻击，而没有当前常规伤口治疗所固有的细胞毒性或微生物抗生素抗性的副作用。我们试图使用一种伤口工程方法来测试这一假设，该方法涉及具有可吸收纳米珠的多层膜，以在伤口表面同时递送可吸收膜和抗菌剂。诸如这样的方法，有助于预防伤口脓毒症，不损害伤口愈合，将代表一个重大的医疗进步。