SYNTHESIS AND AGGREGATION OF CALCIUM CARBONATE IN PHOSPHOLIPID VESICLES

磷脂囊泡中碳酸钙的合成和聚集

• 批准号: 8361302
• 负责人: Derk Joester
• 金额: $ 1.18万
• 依托单位: ILLINOIS INSTITUTE OF TECHNOLOGY
• 依托单位国家: 美国
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-01-01 至 2011-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8361302
• 关键词: Biological; Biophysics; Calcium; Calcium Carbonate; Caliber; Cells; Chemistry; Data; Encapsulated; Funding; Grant; Growth; Hour; In Vitro; Ions; Lead; Lipids; National Center for Research Resources; Phase; Phospholipids; Play; Precipitation; Principal Investigator; Radial; Research; Research Infrastructure; Resources; Role; Salts; Shapes; Source; Surface; System; United States National Institutes of Health; Vesicle; ammonium carbonate; aqueous; cost; nanoparticle; neutrophil; particle

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. Although there is widespread evidence for the use of amorphous precursors in the synthesis of shaped biominerals, the mechanisms of biological synthesis and stabilization remain poorly understood. Research to date has focused largely on the role of additives and organic interfaces in providing transient stabilization. A recent study indicates, however, that amorphous calcium carbonate (ACC) particles formed in bulk appear to be stable below a diameter of 70 nm [1]. The lower surface energy of a meta-stable phase compared to itscrystalline polymorphs could conceivably lead to a threshold size below which the amorphous form is actually the most stable. In mineralizing cells, small vesicles are very likely involved in ACC synthesis, transport, and storage, adding an additional layer of complexity. The small size of the vesicles (30-300 nm), the lipid surface chemistry, and the high radius of curvature may each play an essential role in achieving stability by modulating surface interactions. Here we use an in vitro system, aqueous calcium salts encapsulated within 0.1 - 1 micron diameter unilamellar vesicles, to study this problem. Precipitation is initiated by addition of ammonium carbonate. Preliminary small and wide angle x-ray scattering (SAXS/WAXS) data indicate stabilization of ACC nanoparticles in the range from 10 to 300 nm for at least 13 hours. To extend our analysis, we use SAXS to study precipitation and aggregation of encapsulated ACC nanoparticles. In contrast to bulk precipitation, isolation of the precipitates inside vesicles with limited ion concentration offers a unique control over crystal growth.

该副本是利用资源的众多研究子项目之一 由NIH/NCRR资助的中心赠款提供。对该子弹的主要支持 而且，副投影的主要研究员可能是其他来源提供的 包括其他NIH来源。 列出的总费用可能 代表subproject使用的中心基础架构的估计量， NCRR赠款不直接向子弹或副本人员提供的直接资金。 尽管有广泛的证据表明在形状生物官员的合成中使用了非晶前体，但生物合成和稳定的机制仍然很少了解。迄今为止的研究主要集中在添加剂和有机界面在提供短暂稳定中的作用。然而，最近的一项研究表明，散装形成的无定形碳酸钙（ACC）颗粒似乎稳定在直径下方的70 nm下方[1]。与其晶体多晶型物相比，元稳定相的较低表面能可以想象会导致阈值大小，而无定形形式实际上是最稳定的。在矿化细胞中，小囊泡很可能与ACC合成，运输和储存有关，从而增加了一层复杂性。小囊泡的小尺寸（30-300 nm），脂质表面化学和高度曲率可能通过调节表面相互作用来实现稳定性起着至关重要的作用。在这里，我们使用体外系统，钙盐水溶液封装在0.1-1微米直径的Unilamelar囊泡中，以研究此问题。降水是通过添加碳酸铵引发的。初步的小角度和广角X射线散射（SAXS/蜡）数据表明，ACC纳米颗粒在10到300 nm的范围内稳定至少13小时。为了扩展我们的分析，我们使用SAX研究封装的ACC纳米颗粒的降水和聚集。与散装沉淀相反，离子浓度有限的囊泡内部沉淀物可以对晶体生长产生独特的控制。