Going Local: Probing Real-Time Chemical Exchange Between Biofilm and Dental Composites

 描述（由申请人提供）：复合材料广泛用于牙科修复，但在复合材料寿命方面仍然存在重大缺陷。据估计，大多数牙科复合材料在使用的前10年内失效，主要是由于在牙齿-材料界面处形成细菌生物膜诱导的龋齿。因此，为了开发更持久的牙科修复材料，有必要了解复合材料和口腔生物膜界面的基本化学和生物学。目前，在足够高的空间分辨率下研究该界面以测量细菌代谢活性的分析技术尚不存在。因此，本研究的总体目标是确定牙科复合材料中金属离子（即钙）释放对生物膜生长、代谢和基因表达的影响。释放钙离子以及中和pH的生物活性含玻璃牙科复合材料将被用作模型生物膜生长基质。中心假设是测试不同量的钙离子是否对生物膜生长具有任何显著影响，并确定金属离子是否对产生乳酸的变形链球菌（Sm）和消耗乳酸的小韦荣球菌（Vp）具有任何差异生长影响，使得整体局部pH等于或大于5.5以防止相邻牙齿结构的脱矿。我们将通过以下具体目标来实现我们的假设：我们将制造pH，钙离子和乳酸盐的超微传感器（具体目标1）。然后，这些微传感器将被评估用作扫描电化学显微镜（SECM）探针，以定量绘制含有生物活性玻璃的牙科复合材料上方的化学微环境，有和没有生长的细菌生物膜（Sm和Vp）。这种创新的技术将有助于量化的局部乳酸浓度和由此产生的整体局部pH值的Sm和Vp的存在下，同时暴露于不同量的钙离子释放的复合材料。这些信息将最终导致设计出具有最佳离子释放性能的新型牙科材料，从而使整体局部pH值保持在5.5或更高（具体目标2）。最后，SECM映射数据将用于确定不同复合物制剂、实时氧化还原环境和多微生物生物膜基因表达的相互依赖性（具体目标3）。这项研究是预测下一代“智能”牙科复合材料的重要一步，它将能够阻止产酸生物膜的生长，保持局部pH值的平衡，并最终增加牙科复合材料的使用寿命。

 DESCRIPTION (provided by applicant): Composites are widely used in restorative dentistry, but significant deficiencies in the composite longevity still exist. The majority of dental composie restorations are estimated to fail within the first 10 years of service, mainly due to the formatio of bacterial biofilm-induced caries at the tooth-material interface. Therefore, to develop longer lasting dental restorative materials, it is essential to understand the fundamental chemistry and biology at the interface of the composites and the oral biofilm. Currently, the analytical techniques to study this interface at a sufficiently high spatial resolution to measure bacterial metabolic activity do not exist. Hence, the overall objective of this proposed study is to determine the effects of metal ion (i.e. calcium) release from dental composites on the biofilm growth, metabolism and gene expression. Bioactive glass-containing dental composites that release calcium ions as well as neutralize pH will be used as a model biofilm growth substrate. The central hypotheses are to test whether varying amounts of calcium ions have any significant effect on the biofilm growth and determine whether the metal ions have any differential growth effects on lactate-producing Streptococcus mutans (Sm) and lactate-consuming Veillonella parvula (Vp), such that the overall local pH is equal or greater than 5.5 to prevent demineralization of adjacent tooth structures. We will approach our hypothesis with the following specific aims: We will fabricate ultramicro-sensors for pH, calcium ions and lactate (Specific aim 1). Then, these microsensors will be assessed for use as a scanning electrochemical microscopy (SECM) probe to quantitatively map the chemical microenvironment above dental composites containing bioactive glass, with and without growing bacteria biofilm (s) (Sm and Vp). This innovative technique will help to quantify the local lactate concentration and the resultant overall local pH in the presence of Sm and Vp while exposed to varying amounts of calcium ions released from the composites. This information will ultimately lead to the design of new dental materials with optimal ion releasing property such that the overall local pH remains at 5.5 or higher (Specific aim 2). Finally, SECM mapping data will be used to determine the interdependence of different composites formulations, the real-time redox environment and polymicrobial biofilm gene expression (Specific aim 3). The proposed research is a significant step towards predicting the next-generation "smart" dental composites, which will be able to deter the growth of acidogenic biofilms and to maintain a balance in the local pH and ultimately increase the lifespan of dental composite restorations.