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

生物膜是一种保护性的细胞外聚合物，它包围着细菌菌落， 与超过80%的微生物感染有关。在美国，生物膜的管理成本- 相关的感染达到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遭受生物膜相关的感染， 水肿，并最终阻碍伤口愈合。生物膜细菌对抗生素的耐药性是 自由漂浮的细菌在临床环境中，通常用清创术或生物膜清除术从伤口去除生物膜。 内切酶然而，这些方法不能去除创伤组织深处空间中的生物膜，因此允许在创伤组织中形成生物膜。 生物膜复发。为此，我们最近发明了一种自运动抗菌微型机器人（SLAM）， 可以侵入和去除生物膜。SLAM是通过激活掺杂MnO 2的硅藻生物硅制备的 纳米催化剂（MnO 2-硅藻）以使用3%过氧化氢溶液产生氧微泡。的 活化的MnO 2-硅藻推动自身进入生物膜。在生物膜内，活化的MnO 2-硅藻 继续产生微泡，微泡融合并产生足够高的机械能以使生物膜破裂。它 活化的MnO 2-硅藻需要10分钟去除大于99.9%的0.8 mm厚的铜绿假单胞菌 生物膜的深度与全层皮肤相似。清洁后未观察到不良毒性作用。有了这次成功， 我们的总体目标是使用SLAM改善感染伤口的生物膜去除， 促进伤口皮肤再生我们假设活化的MnO 2-硅藻会使生物膜从 伤口，并反过来增加抗生素对残留生物膜细菌的接触。随后增强的 伤口消毒将用于提高再生医学对伤口中皮肤再生的功效。 我们将通过使用万古霉素和一对角质细胞生长因子（KGF）-2和成纤维细胞来检验这一假设。 生长因子（FGF）-2分别作为抗生素和再生医学的模型。我们的具体目标是：（1） 评估活化的MnO 2-硅藻去除伤口中生物膜的功效，（2）检查活化的MnO 2-硅藻是否具有生物膜活性。 硅藻提高万古霉素防止生物膜再生长的功效，以及（3）调查活化的程度， MnO 2-硅藻增加KGF 2/FGF 2在刺激皮肤再生中的功效。我们将使用以下方法进行每项目标研究： 铜绿假单胞菌或耐甲氧西林S.雄性和雌性CD 1的金黄色葡萄球菌生物膜感染的切除伤口 小鼠我们将使用多模态光学成像评估伤口中的生物膜去除和皮肤再生 通过与具有生物成像专业知识的Boppart集团合作，我们还将确定矩阵 伤口液中金属蛋白酶-9和金属蛋白酶组织抑制剂水平，CD 34 +/CD 45-干细胞 在皮肤科医生Neitzel博士的指导下，SLAM具有活动、促炎症和水肿以及最小的毒性。 总的来说，这项拟议的研究将显著影响治疗不愈合的，生物膜感染的伤口， 创新的SLAM。最后，这项研究将挽救创伤患者的残疾和死亡。

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.