仿生矿化的研究Ⅰ．文石型碳酸钙的合成

在聚乙二醇（ＰＥＯ）存在下，ＣａＣｌ２和Ｎａ２ＣＯ３反应生成了类似红鲍鱼壳的含有ＰＥＯ的碳酸钙──高聚物复合材料。Ｘ－衍射和电镜照片显示，它有两种微观结构：外层为文石型和方解石型结构，内层为针状文石型结构。热重分析表明，该材料中含有３％左右ＰＥＯ。结果说明，聚合物对碳酸钙晶核的形成和晶体的生长有很大影响，并对其形成机理进行了初步探讨。     

气-电纺PHB引导组织再生膜的仿生矿化研究

实验将PHB通过气流-高压静电纺丝制成无纺膜，利用扫描电镜（SEM）、X射线衍射（XRD）对其形态和结构进行表征。在体外研究中，分别将无纺膜样本浸入37℃1．5倍仿生体液（SBF）中3、7、14、28d后对其表面形态和结构进行表征。结果表明，气电纺PHB无纺膜由超细纤维交织而成，纤维之间有多孔形成；通过气流一静电纺丝之后，PHB的结晶度及晶体的有序度降低；PHB膜在SBF中浸泡3天之后就有矿化结晶在纤维的表面形成，随着浸泡时间的增长，矿化结晶的数目增加，结晶度也随之增高，XRD及FTIR表明形成的结晶为含有碳酸根的磷灰石晶体。     

Properties of Magnetite Nanoparticles Produced by Magnetotactic Bacteria

The magnetic nanoparticles(magnetite) were prepared through the fermentation of the Magnetospirillum strain WM-1 newly isolated by our group. The samples were characterized by TEM, SAED, XRD, rock magnetic analysis, and Mossbauer spectroscopy. TEM and SAED measurements showed that the magnetosomes formed by strain WM-1 were single crystallites of high perfection with a cubic spinel structure of magnetite. X-ray measurements also fitted very well with standard Fe3O4 reflections with an inverse spinel structure of the magnetite core. The size of crystal as calculated by the Debye-Scherrer's equation was approximately 55 nm. Rock magnetic analysis showed WM-1 synthesized single-domain magnetite magnetosomes, which were arranged in the form of linear chain. The high delta ratio((δFC / δZFC = 4) supported the criteria of Moskowitz test that there were intact magnetosomes chains in cells. The Verwey transition occurred at 105 K that closed to stoochiometric magnetite in composition. These observations provided useful insights into the biomineralization of magnetosomes and properties of M. WM-1 and potential application of biogenic magnetite in biomaterials and biomagnetism.     

Self-Mineralizing Dnazyme Hydrogel as a Multifaceted Bone Microenvironment Amendment for Promoting Osteogenesis in Osteoporosis

The accumulation of reactive oxygen species (ROS) and minimal osteogenic raw material in the osteoporotic bone microenvironment greatly inhibits the activity of osteoblasts. Herein, it is originally proposed to construct a biomatrix multifaceted bone microenvironment amendment -Mineralized zippered G4-Hemin DNAzyme hydrogel (MDH)-to improve osteoporotic osteogenic capacity and promote high-quality bone defect repair. The programmed design of the rolling circle amplified DNA hydrogel synthesis system allows the introduction of massive amounts of zippered G4-Hemin DNAzyme in MDH. The zippered G4-Hemin DNAzyme highly mimics the tight catalytic configuration of horseradish peroxidase and exerts excellent enzyme-like activity with considerable ROS molecule scavenging ability. In addition, the DNA amplification by-product pyrophosphate is ingeniously employed as a sufficient phosphorus source, thus constituting an autonomous mineralization system for waste reuse through the introduction of pyrophosphate hydrolase and calcium ions, which deposits in MDH as an osteogenic raw material and addresses the challenge of DNA hydrogel bio-application stability. The remarkable in vitro and in vivo outcomes demonstrate that MDH can effectively improve the oxidative stress status of osteoblasts, restore the balance of mitochondrial membrane potential, and reduce apoptosis, ultimately demonstrating superior osteogenic capacity.     

The Formation of Calcified Nanospherites during Micropetrosis Represents a Unique Mineralization Mechanism in Aged Human Bone

Osteocytes—the central regulators of bone remodeling—are enclosed in a network of microcavities (lacunae) and nanocanals (canaliculi) pervading the mineralized bone. In a hitherto obscure process related to aging and disease, local plugs in the lacuno‐canalicular network disrupt cellular communication and impede bone homeostasis. By utilizing a suite of high‐resolution imaging and physics‐based techniques, it is shown here that the local plugs develop by accumulation and fusion of calcified nanospherites in lacunae and canaliculi (micropetrosis). Two distinctive nanospherites phenotypes are found to originate from different osteocytic elements. A substantial deviation in the spherites' composition in comparison to mineralized bone further suggests a mineralization process unlike regular bone mineralization. Clearly, mineralization of osteocyte lacunae qualifies as a strong marker for degrading bone material quality in skeletal aging. The understanding of micropetrosis may guide future therapeutics toward preserving osteocyte viability to maintain mechanical competence and fracture resistance of bone in elderly individuals.     

体外模拟胶原纤维矿化的研究进展

矿化胶原纤维是天然骨的主要成分,掌握胶原纤维的生物矿化过程、原理和调控机制对于骨修复材料的设计及骨组织的再生修复发展有重要意义。综述了体外模拟胶原纤维矿化的研究进展,主要包括胶原纤维内矿化机理和非胶原蛋白对胶原生物矿化的调控作用,以期为胶原生物矿化机理的探讨及骨组织再生修复的研究提供借鉴。     

钛及钛合金仿生表面改性研究进展

钛及钛合金具有较好的生物相容性及优良的机械性能，在临床上得到了越来越广泛的应用。表面生物活性化能够进一步改善其表面性能，提高表面生物活性。本文对钛及其合金的仿生表面改性进行了综述，具体介绍了化学法、促形核剂法、自组装单分子法的活化机理，并对仿生表面改性的发展方向进行了探讨。