可替代HEMA 的Janus纳米复合材料的合成与功能

Tooth adhesive technology using composite resin is the major technology for tooth defect restoration. However, dental adhesives contain HEMA (2-hydroxyethyl methacrylate) as solubilizer, it have three disadvantages: enhanced water-sorption, only have one polymerizable groups that susceptible to hydrolysis, high toxicity. Because of these disadvantages, its imperative to get the HEMA substitution. It had been verified that amphiphilic Janus materials is the ideal materials for interface issues, and the surface modification with special features could be obtained. The Janus nano-composites with unsaturated double bond in hydrophobic side would be prepared by technique of pickering emulsion and etching modification in situ of nano-composites. Regulating the Janus-balance could solve the problem of enhanced water-sorption. By adding the unsaturated double bond in hydrophobic side could increased the cross-link density. Using biocompatible nano silicon dioxide as the subject of Janus nano-composites could reduce cytotoxicity. The research would contribute to a more stable bonding interface and improve the service life of the composite restoration. This research firstly introduce the Janus concept into the stomatology, involving polymer physics and chemistry, stomatology and nano-science. It provide a new perspective for stomatology.

直接粘接修复技术是牙体缺损修复的主流方法。但粘接剂中促进亲水疏水组分混溶的增溶剂HEMA存在三大问题：亲水性过强、仅含一个双键、存在细胞毒性。寻找HEMA替代物成为亟待解决的问题。本课题组以往研究发现具有双亲性的Janus材料是解决不相溶组分间界面问题的理想材料，通过对Janus纳米材料表面改性，可获得具有特殊功能的Janus纳米材料。本研究将借助Pickering乳液法和纳米颗粒原位蚀刻改性技术制备疏水侧含可聚合双键的双亲性Janus纳米材料。调控Janus平衡性参数解决亲水性过强的问题，疏水侧接枝多个双键提高交联密度，使用生物相容性好的纳米二氧化硅作为Janus材料的主体降低细胞毒性。研究结果将有助于形成更稳定的粘接界面，提高修复体使用寿命。本研究首次将Janus材料的理念引入口腔医学研究领域，涉及高分子物理与化学、口腔医学、纳米科学研究，为解决口腔医学问题提供了全新的视角。

双亲性的树脂单体甲基丙烯酸-2-羟乙酯（2-hydroxyethyl methacrylate, HEMA）目前作为牙本质粘接中的预处理剂的主要成分而广泛应用于牙科粘接剂中。它事实上是作为一种稳定粘接剂中亲水成分和疏水成分的增溶剂而存在。但是HEMA存在很多的问题，主要问题为：亲水性过强导致水分存留于粘接界面、在口腔环境中易水解、具有细胞毒性。这些导致牙齿充填修复的失败，增加医疗负担。所以，寻找可替代HEMA的增溶剂成为亟待解决的问题。由于Janus颗粒是一种优越的颗粒乳化剂，可以考虑作为HEMA的替代物。使用Pickering乳液法选择性刻蚀和改性生成具有反应活性的双亲性Janus纳米颗粒。研究表明，其能够作为增溶剂更有效稳定粘接剂各组分，减少相分离。Janus纳米颗粒双侧的基团均能分别和牙本质和树脂基质进行反应，增强了粘接强度。HEMA具有明显的细胞毒性，Janus纳米颗粒则无细胞毒性。因此，我们得出结论，Janus纳米颗粒能够作为一种理想的HEMA的替代物。