Manipulation of Bacterial Metabolism: A New Approach to Develop Smart Dental Composites

提案摘要 在口腔中，怀疑细菌代谢性乳酸产生和相关的pH值变化 在牙科复合材料的寿命和完整性方面发挥关键作用。我们建议 关于牙科细菌代谢物产生的化学微环境的基本知识 材料界面设计下一代牙科复合材料。我们的中心假设是金属离子（Ca 2+， Mg 2+）-释放复合材料可以被工程化以影响细菌代谢并操纵化学物质 微环境，以抑制牙齿脱矿。为了量化这些细菌化学微环境，我们 将采用我们新开发的独特电化学传感器（pH值，乳酸盐，H2 O2，金属离子）来测量 主要的细菌代谢产物，如乳酸和H2 O2在真实的时间。目的1：确定金属离子对 细菌代谢和化学微环境。我们将确定金属离子对 细菌代谢与牙菌斑衍生的微宇宙生物膜，使得局部pH为5.5或更高。到 建立一个遗传上可重复和可再生的生物膜模型，我们将扩大我们的研究，以复制当地的pH值， 乳酸和H2 O2浓度与三种模式生物的不同比例：变形链球菌（乳酸 产生，降低pH）、小韦荣球菌（消耗乳酸）和戈登链球菌（产生H2 O2）。 我们将使用pH、乳酸和H2 O2微传感器作为扫描电化学显微镜（SECM）探针， 确定乳酸盐和H2 O2产生的局部速率以及相应的局部pH变化， 生物膜在金属离子存在下的真实的时间。目的2：定量细菌生物膜上方的局部pH 在金属离子释放BAG复合材料上生长。我们将使用SECM测量牙齿上方20 µm处的pH值 菌斑微宇宙及以上三种生物膜（Sm/Sg/Vp）生长在不同金属离子释放 复合物（与目标1中的浓度范围相似）。这将帮助我们确定是否金属离子释放 来自BAG复合材料的pH可以影响细菌代谢，使得局部pH>5.5。我们还将使用Ca 2 +- 和Mg 2+传感SECM探针，以定量从BAG释放的金属离子的局部浓度 复合材料，以确定离子浓度，细菌将暴露于其中，而生长在这些 复合材料.目的3：真实的实时测量生物膜-复合材料界面处的pH和H2 O2。创新灵活 将在高度动态的材料-生物膜界面处放置金属丝传感器（pH、H2 O2、金属离子）以对其进行监测 并回答一个关键问题：细菌代谢物如何影响生物材料的完整性，金属如何影响生物材料的完整性， 生物材料释放的离子会影响细菌代谢产物吗？拟议的研究提供了一个重要的步骤 旨在确定下一代“智能”牙科复合材料，可以控制生物膜组成， 局部pH值为5.5或更高，从而抑制邻近牙齿的脱矿作用并延长牙齿的寿命。 复合材料

Proposal Summary In the oral cavity, metabolic lactic acid production by bacteria and the associated change in pH are suspected to play a key role in the longevity and integrity of dental composite restorations. We propose gathering fundamental knowledge about the chemical microenvironment created by bacterial metabolites at the dental material interface to design next-generation dental composites. Our central hypothesis is that metal ion (Ca2+, Mg2+)-releasing composites can be engineered to influence bacterial metabolism and manipulate the chemical microenvironment to inhibit tooth demineralization. To quantify these bacterial chemical microenvironments, we will apply our newly developed unique electrochemical sensors (pH, lactate, H2O2, metal ions) to measure major bacterial metabolites such as lactate and H2O2 in real time. Aim 1: Determine the effects of metal ions on bacterial metabolism and the chemical microenvironment. We will determine the effects of metal ions on bacterial metabolism with dental plaque-derived microcosm biofilms such that the local pH is 5.5 or higher. To create a genetically amendable and reproducible biofilm model, we will extend our study to replicate local pH, lactate, and H2O2 concentrations with different ratios of three model organisms: Streptococcus mutans (lactate producing, pH lowering), Veillonella parvula (lactate consuming), and Streptococcus gordonii (H2O2 producing). We will use pH, lactate, and H2O2 microsensors as scanning electrochemical microscope (SECM) probes to determine the local rate of lactate and H2O2 production and the corresponding local pH change above the biofilms in real time in the presence of metal ions. Aim 2: Quantify the local pH above the bacterial biofilms grown on metal ion-releasing BAG composites. We will use SECM to measure pH at 20 µm above the dental plaque microcosm and above three-species biofilm (Sm/Sg/Vp) grown on different metal ion-releasing composites (similar concentration ranges as in Aim 1). This will help us determine whether metal ions released from BAG composites can influence bacterial metabolism such that the local pH is >5.5. We will also use Ca2+- and Mg2+-sensing SECM probes to quantify the local concentration of metal ions released from BAG composites to determine the ion concentration to which bacteria will be exposed while growing on these composites. Aim 3: Measure pH and H2O2 at the biofilm–composite interface in real time. Innovative flexible wire sensors (pH, H2O2, metal ions) will be placed at the highly dynamic material–biofilm interface to monitor it and answer a crucial question: How do bacterial metabolites influence biomaterial integrity and how do metal ions released from biomaterials affect bacterial metabolites? The proposed research provides a significant step towards identifying next-generation “smart” dental composites that can control biofilm composition to maintain a local pH of 5.5 or higher, thus inhibiting adjacent tooth demineralization and extending the lifespan of dental composite restorations.