Interactions of Biomolecules and Bacteria with Titanium at the Mineral Microbe Frontier

该奖项由化学学部环境化学科学项目资助。坦普尔大学的Ann M. Valentine教授被支持探索氧化钛表面与清除金属的生物分子和/或微生物的相互作用。钛在环境和生物体中都非常丰富，并且越来越多地用于消费品和工业应用。钛不被广泛认为是一种生物活性元素，因为它在水中具有极强的惰性和不溶性。本研究考察了二氧化钛粘附（粘附）和从特征良好的生物分子和细菌中释放的能力。清除铁的生物分子特别紧密地结合钛，使其保持可溶性和稳定性。它们还会导致大量钛离子释放到溶液中。本研究揭示了微生物对钛环境化学的影响，揭示了钛的生物学作用。这项研究与一项名为费城环境化学探索（PECE）的新拓展计划相结合，该计划面向即将升入高中的三年级学生。环境生物无机化学是一个扩大科学参与的平台。本项目主要研究清除铁的铁载体和细菌与二氧化钛（TiO2）表面的相互作用。这个研究是无机化学和生物无机化学、生物地球化学、材料和环境化学的交叉领域。铁团与TiO2结合强烈，一些铁团溶解金属氧化物表面的钛离子，在此过程中显著重塑矿物。电子光谱、元素分析和质谱分析揭示了溶液中金属离子的浓度和形态。利用衰减全反射-傅里叶转移红外（ATR-FTIR）以及显微镜等相关技术对溶解前、溶解中、溶解后的氧化物表面和性质进行了探测。钛和铁的相互干扰是一个特别的焦点。微生物/氧化物和生物分子/氧化物的相互作用正在使用橡胶红球菌GIN-1进行研究，这种细菌附着在二氧化钛上，并将大量的钛结合到其生物量中。二氧化钛表面结合蛋白正在被鉴定和表征。它们的丰度和性质与整个生物体的现象有关。钛的摄取被量化，细胞内钛结合分子被分离。在无机化学和生物化学的交叉领域，维持着一个教育和训练本科生和研究生的研究项目。研究活动与化学外展和为即将升入高中的三年级学生开设的新课程相结合。该计划以环境生物无机化学为平台，扩大科学参与。

This award is funded by the Environmental Chemical Sciences Program in the Division of Chemistry. Professor Ann M. Valentine of Temple University is supported to explore the interaction of titanium oxide surfaces with metal-scavenging biomolecules and/or microorganisms. Titanium is very abundant both in the environment and in organisms, and increasingly used in consumer products and industrial applications. Titanium is not widely appreciated as a bioactive element as it has a reputation for extreme inertness and insolubility in water. This research examines the ability of titanium dioxide to stick to (adhere) and release from well-characterized biomolecules and from a bacterium. Iron-scavenging biomolecules bind titanium especially tightly and keep it soluble and stable. They can also cause the release of large quantities of titanium ions into solution. This research sheds light on the impact of microorganisms on the environmental chemistry of titanium and reveals the biological role of titanium. The research is integrated with a new outreach program for rising high school juniors called Philadelphia Environmental Chemistry Explorations (PECE). Environmental bioinorganic chemistry is used as a platform to broaden participation in science. This project focuses on the interactions of iron-scavenging siderophores and bacteria with titanium dioxide (TiO2) surfaces. This inquiry sits at the intersection of inorganic and bioinorganic chemistry, biogeochemistry, and materials and environmental chemistry. Siderophores bind strongly to TiO2, and some siderophores dissolve titanium ions from the metal oxide surface, significantly remodeling the mineral in the process. Electronic spectroscopy, elemental analysis, and mass spectrometry reveal metal ion concentrations and speciation in solution. The oxide surface and properties before, during, and after dissolution are being probed using Attenuated Total Reflectance-Fourier Transfer Infrared (ATR-FTIR) as well as microscopy and related techniques. The mutual interference of titanium and iron is a special focus. Microbe/oxide and biomolecule/oxide interactions are being studied using the bacterium Rhodococcus ruber GIN-1, which adheres to titanium dioxide and incorporates significant quantities of titanium into its biomass. Titanium dioxide surface binding proteins are being identified and characterized. Their abundance and properties are correlate to whole-organism phenomena. Titanium uptake is being quantified and intracellular titanium-binding molecules isolated. A research program is maintained that educates and trains undergraduates and graduate students at the interface of inorganic chemistry and biochemistry. Research activities are integrated with chemistry outreach and with a new program for rising high school juniors. This program uses environmental bioinorganic chemistry as a platform to broaden participation in science.