“去污和矿化”双活性表面诱导釉质样结构再生的自愈性修复

Using bioactive molecules to capture calcium and phosphate ions from saliva to regenerate enamel-like microstructures underlining a cell-free biomimetic mineralization strategy has provided the potential for tooth defect repair via a self-healing mechanism. However, there are 2 key issues for using bioactive molecules to promote self-healing of tooth defects. Firstly, the bioactive molecules must not only have the ability to bind to the tooth surface to capture salivary calcium and phosphate ions, but also possess anti-biofouling properties to inhibit protein and bacterial adhesion to the tooth surface. The anti-biofouling property of the bioactive molecule is very important for in vivo biomimetic mineralization because the salivary proteins (pellicle) and bacterial biofilm (plaque) will adsorb on the tooth surface and disrupt the mineralization..We have developed some kinds of amelogenin-like oligopeptides which mimic the function of amelogenin for regeneration of enamel-like tissue. In this proposal, enamel bonding domain will be grafted to the amelogenin-like oligopeptide or/and an anti-biofouling molecule of polyethylene glycol (PEG) to get three kinds of bioactive molecule. They are ‘[enamel bonding domain]-[amelogenin- like oligopeptide]-[PEG]’, ‘[enamel bonding domain]-[amelogenin-like oligopeptide]’, ‘[enamel bonding domain]-[PEG]’. The enamel bonding domain enable the molecules to bind to enamel surface, the amelogenin-like oligopeptide induces HA crystal assembling into enamel-like tissue as a template, and PEG with “anti-biofouling property” inhibit protein and bacterial adhesion..The synthesized bioactive molecules can adsorb onto the enamel surface to provide anti-biofouling and mineralizing functions. We will evaluate the dual-bioactive surface in vitro and in vivo on the property of binding to enamel surface, the property of anti-biofouling, and the property of inducing enamel-like tissue regeneration. Therefore, we will develop a self-healing therapy to treat tooth defects by capturing mineral ions from saliva.

项目针对“从口腔唾液中摄取矿化离子，仿生矿化诱导釉质样结构再生研究策略”临床转化面临的关键科学问题（矿化活性分子必须具有与牙齿表面结合的能力，诱导牙齿结构的原位再生；同时具有抑制蛋白、细菌粘附的“去污”功能，防止对矿化行为的干扰），提出“构建‘去污-矿化’双活性釉质表面，诱导釉质样结构再生”假设模型。以前期研究获得的可以诱导釉质结构再生的“釉原蛋白仿生寡肽”矿化活性分子为基础，通过接枝改性，接枝“与牙釉质结合的功能域结构”和“去污剂——聚乙二醇（PEG）”，合成“釉质结合的功能结构-釉原蛋白仿生多肽-PEG”、“釉质结合的功能结构-釉原蛋白仿生多肽”、“釉质结合的功能结构-PEG”三种能与牙齿表面结合的“矿化-去污”活性分子，使它们在釉质表面自组装，赋予“矿化-去污”双活性表面。通过体外、体内研究评价活性分子与釉质结合、抑制生物膜形成、以及诱导釉质结构再生作用，为临床转化奠定实验基础。

以龋齿为代表的牙菌斑相关性疾病是最常见的口腔疾病，是目前全球范围内最主要的公共卫生问题之一。人工材料进行龋损修复，伴随术中对健康牙体组织的损伤，及修复过程中人工材料--牙体组织界面的破坏所导致并发症。在龋病初期终止脱矿，启动再矿化，诱导牙体组织的自愈性修复具有重要意义。项目在前期研究基础上，针对“从口腔唾液中摄取矿化离子，诱导釉质样结构再生，仿生矿化研究策略”临床转化面临的关键科学问题（矿化活性分子必须具有与牙齿表面结合的能力，诱导牙齿结构的原位再生；同时具有抑制蛋白、细菌粘附的“去污”功能，防止对矿化行为的干扰），实施“构建‘去污-矿化’双活性釉质表面，诱导釉质样结构再生”的自愈性修复研究。. 研究首先采用分子动力学模拟技术和体外实验技术对与釉质有结合力的相关结构[-多肽SKHKGGKHKGGKHKG-、-Sp-（Sp磷酸化丝氨酸）, -SpSp、-D-DOPA（多巴）-D-DOPA-Lys（赖氨酸）-DOPA-Lys-DOPA]的结合力、抑制脱矿、促进再矿化能力进行了筛选；结果综合结合力、抑制脱矿、再矿化能力考虑，多巴是较理想的选择。其次，研究构建了聚乙二醇（PEG）、全氟三戊胺液态超疏水釉质表面（slippery liquid-infused porous surface (SLIPS)，抗菌肽Histatin 5釉质表面，三种牙齿表面清污体系，综合临床应用、清污能力，研究发现与釉质具有结合性能的 Histatin5 抗菌肽效果做好。研究系统评价了磷酸丝氨酸(Sp)改性的抗菌肽histatin5，即Sp-histatin 5，进行了系统研究，发现其具有与釉质较好的结合性能、抗菌性能、抑制脱矿、促进再矿化形成类釉质结构性能，是一种很有潜力的防龋、抑制脱矿、促进再矿化的治疗制剂。最后，研究采用旋转蒸发技术，以蚕丝纤维蛋白(SF)为矿化模板，开发了一种简单高效的制备类釉质结构的膜材技术，为临床釉质缺损的仿生修复，提供了新的方案，进一步完善了釉质再生理论技术体系。