Self-Locomotive Antimicrobial Micro-Robot (SLAM) Enhancing Biofilm-Infected Wound Healing

项目摘要生物膜是一种包裹在细菌菌落周围的保护性胞外聚合物， 与80%以上的微生物感染有关。在美国，生物膜的管理成本- 相关感染高达940亿美元，每年造成50万人死亡。特别是， 数以百万计的伤口患者患有生物被膜相关感染，导致持续炎症和 浮肿，并最终阻碍伤口愈合。生物被膜细菌对抗生素的抗药性是 自由漂浮的细菌。在临床环境中，通常通过清创或去除伤口上的生物膜。 酵素。然而，这些方法不会去除伤口组织深处的生物膜，因此可以 生物膜复发。为此，我们最近发明了一种自主运动的抗菌微型机器人(SLAM)，它可以 可以入侵并清除生物膜。SLAM是由掺杂MnO2的硅藻生物二氧化硅活化而成 纳米催化剂(MnO2-硅藻)使用3%的过氧化氢溶液产生氧气微泡。这个 被激活的MnO2-硅藻推动自己进入生物膜。在生物膜内，活化的MnO2-硅藻 继续产生微泡，这些微泡融合并产生足够高的机械能来破坏生物膜。它 活化的MnO2-硅藻对0.8 mm厚的铜绿假单胞菌的去除效果在10分钟内达到99.9%以上 生物膜的深度与全层皮肤相似。清洗后未见不良毒性反应。有了这样的成功， 我们的总体目标是使用SLAM改善感染伤口的生物膜去除，并反过来促进 皮肤在伤口中再生。我们推测，被激活的二氧化锰硅藻会将生物膜从 并反过来增加抗生素对残留生物被膜细菌的利用。随后得到增强的 创面消毒有助于提高再生医学对创面皮肤再生的疗效。 我们将通过使用万古霉素和一对角质形成细胞生长因子(KGF)-2和成纤维细胞来验证这一假设 生长因子-2分别作为模型抗生素和再生医学。我们的具体目标是：(1) 评价活性二氧化锰-硅藻去除创面生物膜的效果，(2)检测活化的二氧化锰-硅藻 硅藻提高万古霉素防止生物膜再生长的效果，以及(3)调查被激活的程度 二氧化锰-硅藻提高KGF2/FGF2刺激皮肤再生的功效。我们将使用以下工具进行每项目标研究 铜绿假单胞菌或耐甲氧西林金黄色葡萄球菌生物被膜感染CD1男女切除创面 老鼠。我们将使用多模式光学成像来评估创面的生物膜去除和皮肤再生 通过与在生物成像方面拥有专业知识的BopPart小组合作，该系统将成为一种新型的生物成像系统。我们还将确定矩阵 创面液中金属蛋白酶-9及其组织抑制物水平、CD34+/CD45-干细胞 在皮肤科医生Neitzel的指导下，SLAM的动员、促炎和水肿以及最小的毒性。 总体而言，这项拟议的研究将显著影响使用以下技术治疗未愈合的生物膜感染伤口的努力 创新的大满贯。最终，这项研究将使创伤患者免于残疾和死亡。

Project Summary Biofilm, a protective extracellular-polymeric substance that surrounds bacterial colonies, is associated with more than 80% of microbial infections. In the United States, the management cost for biofilm- associated infections reaches 94 billion US dollars and is responsible for 0.5 million deaths annually. In particular, millions of wound patients suffer from biofilm-associated infections that lead to persistent inflammation and edema, and ultimately hinder wound healing. Biofilm bacteria are 1,000 times more resistant to antibiotics than free-floating bacteria. In a clinical setting, it is common to remove biofilm from the wound with debridement or enzymes. However, these methods do not remove biofilm in space deep in the wounded tissue, thus allowing biofilm recurrence. To this end, we recently invented a self-locomotive, antimicrobial micro-robot (SLAM) that can invade and remove biofilm. The SLAM is prepared by activating diatom biosilica doped with MnO2 nanocatalysts (MnO2-diatom) to generate oxygen microbubbles using a 3 % hydrogen peroxide solution. The activated MnO2-diatoms propel themselves to enter the biofilm. Within the biofilm, the activated MnO2-diatoms continue to generate microbubbles that fuse and produce mechanical energy high enough to fracture biofilm. It takes 10 minutes for the activated MnO2-diatoms to remove more than 99.9 % of 0.8 mm-thick P. aeruginosa biofilm with similar depth to full-thickness skin. No adverse toxic effects are observed after cleaning. With this success, our overall goals are to improve biofilm removal from the infected wound using SLAM and, in turn, to promote skin regeneration in the wound. We hypothesize that the activated MnO2-diatoms would detach biofilm from wounds and, in turn, increase access of antibiotics to residual biofilm bacteria. The subsequently enhanced wound disinfection would serve to improve the efficacy of regenerative medicine to skin regeneration in wounds. We will examine this hypothesis by using the vancomycin and a pair of keratinocyte growth factor (KGF)-2 and fibroblast growth factor (FGF)-2 as a model antibiotic and regenerative medicine, respectively. Our specific aims are to: (1) evaluate the efficacy of activated MnO2-diatoms to remove biofilm in wounds, (2) examine if activated MnO2- diatoms improve the efficacy of vancomycin to prevent biofilm re-growth, and (3) investigate the extent that activated MnO2-diatoms increase the KGF2/FGF2 efficacy in stimulating skin regeneration. We will conduct each aim study using the P. aeruginosa or methicillin-resistant S. aureus biofilm-infected excisional wound of male and female CD1 mice. We will assess the biofilm removal and skin regeneration in wounds using a multimodal optical imaging system through collaboration with the Boppart group with expertise in bioimaging. We will also determine the matrix metalloproteinase-9 and tissue inhibitor to metalloproteinase levels in the wound fluid, CD34+/CD45- stem cell mobilization, pro-inflammation and edema, and minimal toxicity of SLAM under guidance by Dr. Neitzel, a dermatologist. Overall, this proposed study will significantly impact efforts to treat non-healing, biofilm-infected wounds using innovative SLAMs. In the end, this study will save wound patients from disability and death.