"Nanostructured Block-copolymer Reinforced Calcium Phosphate Composites

“纳米结构嵌段共聚物增强磷酸钙复合材料

• 批准号: 7277039
• 负责人: LARA A ESTROFF
• 金额: $ 24.55万
• 依托单位: CORNELL UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-06-01 至 2010-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7277039
• 关键词: Nanostructured; Block; copolymer; Reinforced; Calcium

DESCRIPTION (provided by applicant): The broad objective of this proposal is to develop synthetic methodologies towards next generation dental restorative composites that have a nanostructured arrangement of the inorganic and organic components, similar to the structures found in dentin and enamel. The self-hardening composites synthesized as part of this proposed work will have applications in the repair of dental cavities caused by caries. Our approach is to combine calcium phosphate minerals with the well-established ability of amphiphilic (hydrophobic/hydrophilic) block copolymers to direct the assembly of inorganic materials into mesostructured hybrids (with e.g., cylindrical, lamellar, or bicontinuous morphologies). We will start from amorphous calcium phosphate particles as a precursor phase, which, after structure formation with the block copolymers, will be crystallized to form robust composites with apatite (Ca10(PO4,CO3)6(OH)2) nanocrystals as the inorganic component. The synthesis of the materials will be completed with four specific aims: 1) Synthesis and characterization of stable amorphous calcium phosphate (ACP) particles (< 100 nm) capable of forming stable suspensions in both aqueous and organic solvents. 2) Use of amphiphilic diblock copolymers to direct the assembly of ACP particles into materials with defined 1-D, 2-D, and 3-D nanostructures. 3) Controlled crystallization of the amorphous, inorganic phase of the nanostructured composites. 4) Development of self-hardening composites by mixing powders of the nanostructured composites developed in Aims 2 and 3 with an aqueous liquid phase to induce secondary crystallization. The design of these new composites for dental restoration represents a paradigm shift away from traditional materials with isolated inorganic particles embedded within a continuous polymer matrix to composites with a continuous inorganic phase penetrated by polymer. The benefits of a continuous inorganic phase include a reduction (or even elimination) of shrinkage of the composites as they harden, improved abrasion (wear) resistance, and stronger materials. Mechanically, the amphiphilic blockcopolymer as the organic component will provide toughness and fracture resistance to the composite. The adhesion of these self-hardening composites to the natural tooth should be better than the traditional resins since we are using a water-based system that will be able to infiltrate the hydrated dentin. The flexibility of the block copolymer system will allow us in the future to tailor the mesostructure of the composites to form materials whose mechanical properties best match the part of the tooth (e.g., dentin or enamel) being repaired. This research is consistent with the R21 philosophy in that the ability of amphiphilic block copolymers to phase segregate into nanostructured films has never been applied to the structuring of calcium phosphate mineralization.

描述（由申请人提供）：该提案的广泛目标是针对下一代牙科修复材料开发合成方法，这些复合材料具有无机和有机成分的纳米结构排列，类似于牙本质和搪瓷中发现的结构。作为这项拟议作品的一部分合成的自我硬化的复合材料将在修复龋齿引起的牙齿腔中应用。我们的方法是将磷酸钙矿物质与两亲性（疏水/疏水性）的良好能力相结合，以将无机材料的组装引导到介于介质的杂种中（例如，圆柱形，层状，薄片或双层型形成型）。我们将从无定形磷酸钙颗粒作为前体相开始，在与块共聚物形成结构后，将结晶以与磷灰石（CA10（PO4，CO3，CO3）6（OH）2）纳米晶体形成稳健的组合材料，作为无机分量。材料的合成将以四个特定的目的完成：1）稳定的无定形磷酸钙（ACP）颗粒（<100 nm）的合成和表征，能够在水性和有机溶剂中形成稳定的悬浮液。 2）使用两亲性二嵌段共聚物将ACP颗粒组装到具有定义的1-D，2-D和3-D纳米结构的材料中。 3）纳米结构复合材料的无定形无机相结晶。 4）通过将AIM 2和3中在AIM 2和3中开发的纳米结构复合材料的粉末与水相结合的粉末混合使用水相结晶的粉末来开发自我刻痕的复合材料。这些用于牙齿修复的新复合材料的设计代表了从传统材料中的范式转移，这些材料嵌入了连续的聚合物基质中，嵌入了连续的聚合物基质到具有连续的无机相的复合材料，并被聚合物穿透。连续无机阶段的好处包括减少（甚至消除）复合材料的收缩，它们硬化，改善耐磨性（磨损）耐药性和更强的材料。从机械上讲，作为有机成分的两亲性区块聚合物将为复合材料提供韧性和抗断裂性。这些自我硬化的复合材料对天然牙齿的粘附应该比传统树脂更好，因为我们使用的是水基系统，该系统将能够渗入水合的牙本质。块共聚物系统的灵活性将使我们在将来量身定制复合材料的介质结构，形成其机械性能最能与牙齿的一部分（例如牙本质或搪瓷）相匹配的材料。这项研究与R21哲学是一致的，因为两亲性块共聚物将分离成纳米结构膜的能力从未应用于磷酸钙矿化的结构。