Cerium oxide particles as functional haloperoxidase mimics to combat biofouling

水生生境中的表面通常被微生物定殖。一个教科书上的例子是细菌、单细胞生物、藻类或贝壳在船舶或港口设施上的定居。减少这种所谓的生物污垢的当前策略是在涂料中添加杀生物剂。微生物在生物膜的形成中进入协同群落，并通过经由信号分子的信号传导（“群体感应”）来协调膜的形成。海洋生物的防御机制是基于通过酶促形成卤代-因此无效-信号分子来破坏表生体的细胞间通信。拟议的项目使用CeO 2-x纳米颗粒（NP）酶（卤代过氧化物酶）模拟物，其-类似于天然卤代过氧化物酶-催化过氧化氢（在日光下产生）氧化无处不在的卤化物。生成的次卤酸（HOX）中间体与有机底物反应，形成卤化信号分子。金属氧化物颗粒可以作为涂料和树脂的成分固定在表面上而不失去其效果。卤化信号化合物的催化卤化已在实验室实验中得到证实。该项目旨在通过汇集项目合作伙伴的专业知识来实现以下目标：1.解开卤化反应的顺序：反应是通过短寿命的HOBr/HOCl中间体进行的，还是涉及其他活性中间体？哪些卤代信号化合物在天然沃茨中形成（即，在外地）？这些卤代主要中间体的稳定性如何？它们的形成浓度如何？还形成了哪些化合物？2. CeO_（2-x）NP在卤化反应中的催化活性是由缺陷决定的。通过增加不同固态溶液系列中的缺陷浓度（例如，CeO2-M2O3，（M = La，Y，Bi等）活性有待提高。替代卤化催化剂：除了CeO 2-x及其取代变体的卤化性能外，Ce钙钛矿（BaCe 1-xO 3-y等）的卤化活性，将测试铈取代的二氧化硅化合物（Ce-TUD-1）、铜铁矿型复合材料（CuCrO 2-CeO 2）或锰氧化物。CeO 2-x NP（和可能的替代品）在化学品应用中的使用要求有足够的可用性。合成必须按比例放大到公斤规模。涂层的电阻及其表面性能的分析检测和优化：颗粒应整合到薄膜或涂层中，以便在面向应用的条件下使用。 必须优化表面特性，确定薄膜上的细菌和藻类生长以及颗粒的沥滤（环境相容性）和释放的产品。

Surfaces in aqueous habitats are usually colonized by microorganisms. A textbook example is the settlement of bacteria, unicellular organisms, algae or shells on ships or port facilities. A current strategy to reduce this so-called biofouling is the addition biocides in paints. Microorganisms enter into synergistic communities in the formation of biofilms and co-ordinate film formation through signaling via signaling molecules ("quorum sensing"). A defense mechanism of marine organisms is based on disrupting cell-to-cell communication of epibionts by enzymatic formation of halogenated - and thus ineffective - signaling molecules. The proposed project uses CeO2-x nanoparticle (NP) enzyme (haloperoxidase) mimics, which - analogously to natural haloperoxidases - catalyze the oxidation of ubiquitous halides by hydrogen peroxide (generated in daylight). The resulting hypohalous acid (HOX) intermediates react with organic substrates in follow-up to form the halogenated signal molecules. The metal oxide particles can be immobilized on surfaces as a constituent of paints and resins without losing their effect. The catalytic halogenation of a halogenated signal compound has been demonstrated in laboratory experiments. The project aims to achieve the following objectives by pooling the expertise of both project partners:1. Unraveling the sequence of the halogenation reactions: Does the reaction proceed via short-lived HOBr/HOCl intermediates, or are other reactive intermediates involved? Which halogenated signaling compounds are formed in natural waters (i.e., in the field)? What is the stability of these halogenated primary intermediates and in what concentrations are they formed? Which other compounds are formed?2. The catalytic activity of CeO2-x NP in halogenation reactions is determined by defects. By increasing the defect concentration in different solid state solution series (e.g., CeO2-M2O3, (M = La, Y, Bi, etc.) the activity should be improved.3. Alternative halogenation catalysts: Besides the halogenation properties of CeO2-x and its substituted variants, the halogenation activity of Ce perovskites (BaCe1-xO3-y etc.), Ce-substituted silica compounds (Ce-TUD-1), delafossite-type composites (CuCrO2-CeO2), or Mn oxides will be tested.4. The use of CeO2-x NP (and possible alternatives) in antifouling applications requires the availability in sufficient amounts. The synthesis must be scaled up to the kg scale.5. Analytical examination and optimization of the resistance of the coatings and their surface properties: The particles should be integrated into films or coatings for use under application oriented conditions. The surface properties must be optimized, the bacterial and algae growth on the films and the leaching of the particles (environmental compatibility) and the released products will be determined.