Metal-titanates, novel anti-caries catalysts for modulating the virulence of cariogenic biofilms

项目总结 龋齿是一种流行但可预防的口腔疾病。在龋齿活跃的受试者中，有一种向 微生物群落以产酸细菌和耐酸细菌为主。变形链球菌是一种主要的 致龋性病原体。共生菌通常通过生物活性产品帮助控制变形链球菌，如 过氧化氢。然而，经常出现在龋齿发生率较高的人群中的高糖摄入量 发展，可以通过抑制碳水化合物分解代谢抑制过氧化氢的产生，从而 破坏动态平衡。几种金属钛酸盐最近已成为有效的绿色化学解决方案 产生活性氧(ROS)，包括过氧化氢、O2·-、·OH和1O2。它们会在体内引发氧化应激 某些细菌，并随后抑制它们。金属钛酸盐具有广泛的牙科应用潜力 由于与各种牙科材料，包括牙科粘合剂系统，树脂复合材料， 陶瓷和金属。此外，作为光催化剂，金属钛酸盐不会在催化的 反应，但可以持续行动，从而提供长期的好处。我们的团队已经证明了金牌 钛酸盐可以催化产生过氧化氢，对变形链球菌有灭活作用，但对细菌的影响有限。 口腔共生细菌戈登链球菌和血链球菌。据推测，选择性光活化 半导体金属钛酸盐会在O2还原过程中产生外在的过氧化氢和其他ROS来抑制S. 变种，同时为共生细菌提供优势，从而维持牙齿生物膜的动态平衡 从而预防龋齿。为了验证我们的假设，目标1将优化金属的应用条件。 钛酸盐，以最大限度地发挥抗菌功效的潜力。我们将测量不同种类的RO 用原位探针化合物从钛酸金生产。然后，我们将合成半导体金属 钛酸盐，以增强光催化活性(即可见光活化，产生更多ROS)和 改善临床表现(例如，美观、配伍、物理特性、稳定性和毒性)。目标2将 确定金属钛酸盐对变形链球菌和共生菌基因表达的影响。转录本 突变链球菌与金属钛酸盐的图谱将通过mna测序(rna-seq)和氧化 与压力相关的基因将受到专门的监测。目标3将专注于多样化的多物种口腔生物膜， 尤其是在高糖条件下。首先，我们将研究金属钛酸盐对空间组织的影响 以及流动细胞系统中变形链球菌和共生菌的双种生物膜的组成。第二, 我们将应用菌斑衍生的多菌种微生物膜和变形链球菌感染的多菌种口腔微生物 社区了解口腔复杂生物膜中的物种对口腔中金属钛酸盐的反应 空洞，其中16S rRNA基因测序将被用来测量组成位移。总而言之， 这项研究将提供一个全面的理解，金属钛对形成和 生态牙科生物膜，并指导开发有效的牙科应用。

PROJECT SUMMARY Dental caries is a prevalent but preventable oral disease. In caries-active subjects, there is a shift towards a microbial community dominated by acidogenic and acid-tolerant bacteria. Streptococcus mutans is a major cariogenic pathogen. Commensal bacteria normally help to control S. mutans via bioactive products such as H2O2. However, high-sugar consumption, which is frequently found in populations with a high rate of caries development, could inhibit the generation of H2O2 through carbohydrate catabolite repression and thereby disrupt homeostasis. Several metal titanates have recently emerged as effective green chemistry solutions to produce reactive oxygen species (ROS), including H2O2, O2˙–, ˙OH, and 1O2. They trigger oxidation stress in certain bacteria and subsequently inhibit them. Metal titanates have the potential for broad dental applications due to high compatibility with various dental materials, including dental adhesive systems, resin composites, ceramics, and metals. Furthermore, as photocatalysts, metal titanates will not be consumed in the catalyzed reaction but can act continuously, thus offering long-lasting benefits. Our group has demonstrated that gold titanate could catalyze and produce H2O2, which could inactivate S. mutans while having limited impact on commensal oral bacterial S. gordonii and S. sanguinis. It is hypothesized that selective photoactivated semiconducting metal-titanates will produce extrinsic H2O2 from O2 reduction and other ROS to inhibit S. mutans, while giving an advantage to commensal bacteria and thereby maintain homeostasis in dental biofilms and thus prevent dental caries. To test our hypothesis, Aim 1 will optimize the application conditions of metal titanates to maximize the potentials of the antibacterial efficacy. We will measure different species of ROS production from gold titanate with in situ probe compounds. Then, we will synthesize semiconducting metal titanates to enhance the photocatalytic activities (i.e., activation by visible light, more ROS generation) and improve clinical performances (e.g., esthetics, compatibility, physical property, stability, and toxicity). Aim 2 will identify the gene expressions of S. mutans and commensals exposed to metal titanates. The transcriptional profiles of S. mutans with metal titanates will be revealed by mRNA sequencing (RNA-seq) and the oxidative stress relevant genes will be specifically monitored. Aim 3 will focus on diverse multi-species oral biofilms, especially in high sugar condition. First, we will examine the effect of metal titanates on the spatial organization and composition of the dual-species biofilms of S. mutans and commensal bacteria in flow cell system. Second, we will apply plaque-derived multispecies microbial biofilms and S. mutans-infected multispecies oral microbial community to understand the response of species within complex oral biofilms to metal titanates in the oral cavity, for which 16S rRNA gene sequencing will be employed to measure the composition shift. Collectively, the study will provide a comprehensive understanding of the effects of metal titanates on the formation and ecology of dental biofilms and guide the development of an effective dental application.