唾液在天然牙表面的自组装成膜与生物润滑机制研究

With the high incidence of cancer and population aging, xerostomia (also called as “dry mouth”) becomes increasingly commonplace as a result of impaired salivary gland function. Xerostomia is a condition characterized by a reduction or loss in salivary lubrication, and thus severe tooth wear and swallowing disorder occur, resulting in a bad quality of patients' life. Nowadays there are no effective treatments for xerostomia, and patients can only use artificial saliva to relieve symptoms. Due to bad film-forming properties and weak lubrication, currently available artificial saliva is very far from the requirement in patients. It has become urgent to investigate the film-forming and lubrication properties of natural human saliva and then develop new high-performance artificial saliva. Therefore, this project is to systematically investigate the formation and bio-lubrication mechanisms of self-assembled salivary pellicle on human teeth and then develop new high-performance artificial saliva by means of experimental study, biostatistics analysis and numerical simulation. Firstly, based on identifying the effects of various factors on the absorption of salivary proteins upon human teeth, the regulatory mechanism of salivary proteins during the formation process of self-assembled salivary pellicle will be studied. Secondly, the anti-wear and friction-reducing mechanism of salivary pellicle under protein-protein interactions will be explored. Finally, through the construction of the model for the bio-lubrication of natural human saliva, the optimizing bionic design guideline based on tribology will be proposed to develop new high-performance artificial saliva. This research will not only have significant theoretical value for developing bio-tribology theoretical system, but also contribute to the improvement of people’s life quality and then have great social benefits and application value.

癌症高发和老龄化显著增加了唾液腺功能受损的几率，导致口干症的发病率急剧上升。口干症患者的唾液润滑作用锐减或丧失，患者牙齿磨损加剧，吞咽困难，生活质量严重下降。目前，口干症无有效治疗手段，患者只能通过服用人工唾液缓和症状。现有人工唾液成膜性差、润滑作用有限，远不能满足患者需求，亟需研究天然唾液的成膜与润滑机制，进而开发高性能人工唾液。为此，本项目拟通过实验研究、生物统计学分析和数值模拟相结合，系统开展唾液在天然牙表面的自组装成膜与生物润滑机制研究。在阐明唾液蛋白吸附成膜影响规律的基础上，研究唾液蛋白对自组装成膜过程的调控机理，探明唾液膜在多蛋白交互作用下的降摩减磨机理，揭示唾液膜的生物润滑机制，构建人体天然唾液的生物润滑模型，建立新一代高性能人工唾液的摩擦学仿生设计准则。相关研究不仅对丰富发展生物摩擦学学科理论体系具有重要的理论价值，而且有助于改善人民生命质量，具有重大的社会效益和应用价值。

口腔表面的唾液蛋白吸附膜具有优异的润滑作用，对咀嚼、发音和吞咽十分重要。癌症高发和人口老龄化导致唾液腺功能受损人群增多，口干症发病率显著提高。口干症暂无有效治疗手段，患者只能通过服用人工唾液缓解症状，然而，现有人工唾液成膜性差、润滑作用有限，远不能满足患者需求。目前，相关研究大多侧重唾液膜成分、结构和理化特性的表征，缺乏针对唾液蛋白吸附膜润滑机理的系统研究。因此，亟需系统研究天然唾液蛋白的吸附成膜与润滑机制，为开发高性能人工唾液提供理论和技术支撑，并为仿生润滑提供新思路。.本项目针对天然唾液润滑的关键科学问题，系统开展了唾液蛋白在天然牙表面吸附成膜与润滑行为的影响因素、唾液膜的润滑机制和基于唾液膜润滑机制的相关应用等研究。结果显示，唾液膜的润滑作用主要归因于唾液蛋白在口腔表面的有序组装。低分子量蛋白通过静电作用在牙齿表面形成具有平滑连接能力的内层膜，高分子量蛋白通过氢键/范德华力在内层膜表面形成具有优异承载能力的外层膜。在两层膜的协同作用下，唾液蛋白吸附膜为牙齿提供有效润滑。唾液流率、口腔化学环境等因素均会影响唾液蛋白在牙齿表面的吸附与润滑行为，其中，唾液流率越大，唾液蛋白在牙齿表面形成具有稳定多层膜结构的唾液蛋白吸附膜的时间越短，而口腔摄入的乙醇、酸性物质和多酚等会破坏唾液膜的有序多层膜结构，导致其润滑性能被极大地削弱，甚至丧失。研究还发现，钙离子能够作为配体连接唾液蛋白、促进蛋白团聚，使得牙齿表面唾液膜的厚度、粘弹性和承载能力增大，从而提高口腔表面唾液蛋白吸附膜的润滑性能，因此，钙离子具有诱导唾液润滑强化的能力，这为开发低成本高性能的离子型人工唾液提供了重要技术支撑。.本项目研究揭示了人体天然唾液的生物润滑机制，丰富和发展了生物摩擦学的研究内容，为仿生润滑提供了理论指导，并为新一代高性能人工唾液和牙科修复材料的研发提供了重要技术支撑。