这项工作是由协同Ceramisys有限公司的EPSRC CASE助学金和支持也与米德求新，EPSRC中心相关于医疗器械[授权号EP / K029592 / 1]创新制造。笔者也想在谢菲尔德哈勒姆大学，感谢罗伯特·伯顿的XRF分析。

<img alt="图1" src="/files/ftp_upload/55343/55343fig1.jpg" /> 图1.仿生纳米羟基磷灰石的快速混合配制的示意图。磷酸溶液倒入氢氧化钙悬浮液中。该悬浮液定居过夜后，将羟基磷灰石是用去离子水洗涤，在60至80℃干燥之前。的羟基磷灰石然后在玛瑙研钵和杵及烧结研磨调查磷灰石产物的热稳定性。 <a href="https://ecsource-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/55343/55343fig1large.jpg" target="_blank">请点击此处查看该图的放大版本。</a> 1.纳米羟基磷灰石的快速混合生产<ol><li>钙，磷的解决方案，准备使用钙与磷1.67摩尔比为准备5克纳米羟基磷灰石。 <ol><li>添加3.705克氢氧化钙与500ml的去离子水搅拌在磁力搅拌器板以400rpm 1小时。 </li><li>在一个单独的烧杯中，溶解3.459克的在250毫升去离子水的磷酸（85％）。 </li></ol></li><li>倾磷溶液倒入搅拌的氢氧化钙悬浮液在大约100毫升/秒的速率。用封口膜封住（Bemis公司，USA）烧杯中。 </li><li>离开该悬浮液搅拌在400rpm 1小时。 </li><li>就拿烧杯关闭搅拌器板，并留下沉降过夜。 </li><li>通过倾倒掉上清，加入500毫升去离子水并在400rpm下搅拌1分钟，洗该悬浮液。重复此步骤三次总共，每次洗涤之间2小时。 </li><li>离开纳米羟基磷灰石悬挂沉降过夜。 </li><li>倒出上层清液，然后将结算磷灰石悬浮液在烘箱中于60至80℃的干燥。 </li><li>干燥时，将干燥的羟基磷灰石到玛瑙研钵和研杵和研直到细。 </li><li>有2.5克的亲duced磷灰石粉末在氧化铝坩埚并烧结粉末在1000℃2小时，使用10℃/分钟的升温速率。热处理后，离开磷灰石在炉内冷却。 </li><li>商店的粉末在真空干燥器。 </li></ol> 2.纳米羟基磷灰石的表征<ol><li> 使用的传输模式的衍射仪的X射线衍射（XRD） <ol><li>放置聚（乙烯醇）的少量（ 即小于200微升）（PVA）胶醋酸膜和与羟基磷灰石粉末的少量（ 即小于100毫克）混合。 </li><li>用热风枪，直到干燥处理。 </li><li>装入样品到样品保持器和负载到具有Cu的Kαα辐射的传输模式X射线衍射仪。 </li><li>使用40千伏和35毫安衍射设置，以10〜70°的2θ范围内。 </li><li>分析产生的X射线衍射图案。 </li><li>使用相鉴定以下XRD卡:羟基磷灰石:9-432。 β磷酸三钙:04-014-2292。 </li></ol></li><li> 透射电子显微镜（TEM） <ol><li>放置粉末在茹少量（ 即小于10毫克）和增加大约3毫升乙醇中。 </li><li> 15超声处理样品 - 30分钟直到一个均匀的悬浮液是观察。 </li><li>吸取少量的溶液（ 即低于1毫升以下）到具有碳膜400目铜网上，并晾干。 </li><li>图像样品在80千伏的加速电压。 </li></ol></li><li> X射线荧光（XRF）的材料与工程研究所（梅里）在谢菲尔德哈勒姆大学服务 <ol><li>结合0.8克纳米羟基磷灰石粉末与8克四硼酸锂。 </li><li>熔化在使用炉设置为1200℃的铂 - 金合金坩混合物。 </li><li>在X射线荧光光谱仪分析所得的样品，以确定的元素组成样本。 </li></ol></li><li> 傅立叶变换中衰减全反射模式红外光谱（FTIR-ATR） <ol><li>从4000执行64后台扫描- 400 -1用4厘米-1的分辨率。 </li><li>放置磷灰石粉末在金刚石的顶端少量（ 即小于100毫克）在衰减全反射模式适配器和压缩到使用螺丝顶部金刚石的表面上。 </li><li>从4000执行扫描32 - 400 -1为4厘米的分辨率-1从样品扫描减去后台扫描。 </li></ol></li></ol>

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作者什么都没有透露。

天然磷灰石是由具有钙10-XY的近似化学式[（HPO 4）（PO 4）] 6-X（CO 3）Y（OH）2-X型非化学计量碳酸羟磷灰石纳米颗粒。于天然存在的矿物已经报道了生产接近化学相似的生物材料，以促进最佳的生物反应。例如，在仿生缺钙碳酸磷灰石的研究已经表明，它是能刺激增殖和鼠前成骨细胞的细胞的碱性磷酸酶活性更大程度比常规磷灰石19。 在这项研究中，HA的这表明局部热分解在1000℃（ 图2）的析出建议缺钙的HA的生成。用X射线荧光光谱数据获得的P比（1.63）（T:这是由比化学计量的Ca下部支承能1）。可以理解的是一个减小的Ca:P比与较低的热稳定性20，21，22，23相关联。在该方法中，迅速加入磷酸溶液急剧降低反应悬浮液的pH以产生HPO 4离子。 HPO存在4组促进钙缺乏的HA的沉淀，用分子式为Ca 10-X（HPO 4）×（PO 4）6-X（OH）2-x，其中0 &lt;X &lt;1。 因此，迅速加入磷酸对反应的沉淀动力学有显着影响。如前所述，涉及在室温下进行的氢氧化钙和磷酸滴定反应倾向于具有高的纵横比13，以产生颗粒。对于titratioÑ涉及这些反应物的反应，有必要使用升高的温度，以产生具有较低纵横比这更类似于生物磷灰石13的颗粒。当晶体成核速率比晶体生长速率24慢的高纵横比的颗粒产生。在这项研究中开发的新方法，迅速加入磷酸溶液可能提供这导致小的圆形颗粒的存在增加，而不是更少的粒子具有较大的长宽比成核位点的更大的数字。如作者还没有充分研究的缓慢浇注磷酸成氢氧化钙悬浮液中，以达到一致的结果的影响，我们建议的磷酸在视频（大约100毫升/显示与相称的速率倾S）。 在该方法的发展，作者INVestigated一些增量变化的基础上普拉卡什等人芽制备方法。 13，包括与缓慢滴定并迅速加入磷酸溶液25的所生产的产品的比较。我们发现的磷酸的缓慢滴定入氢氧化钙悬浮液导致与氢氧化钙残基的产物。我们建议，所造成的快速加入磷酸的pH变化鼓励氢氧化钙的溶解，因此，允许对成功转化的反应物到羟基磷灰石。的产品的比较使用在室温和升高的温度（60℃）快速混合方法制备发现升高的温度导致更高的导电性的反应完成后。这表明，残留的氢氧化钙存在这很可能是由于氢氧化钙中的溶解度较低温度升高。残留的氢氧化钙的存在是不希望的，该化合物的基本性质可能危及生物相容性。 红外探测用HA（ 图3）相关联的特性磷酸酯和羟基基团的活性。有人指出，对于烧结产品的光谱显示更清晰磷酸盐和羟基峰。这些变化已经与一个更大的产品结晶度26，27提供的B型碳酸替代，其中碳酸根离子已经取代磷酸基团的证据.The烧结谱有关。这是相对于A型的取代，其中碳酸根离子可以取代的羟基17。据报道，B型碳酸盐替代在生物磷灰石3发生。然而，Tampieri 等。报告说，虽然B型取代是predomin蚂蚁在骨头青年，A型碳酸盐替代是老年人28骨头越来越呈现。碳酸盐替代已发现减小磷灰石的结晶度和热稳定性，而增加其溶解度。这些变化已经提出向碳酸取代的HA 29的增加生物活性。还已知的生物的HA含有一些记录在X射线荧光分析（ 表1）的其他元素，如镁，钠，锶30的。这些元素的存在也可能有助于提高生物效力。今后的工作应在这些纳米取代磷灰石的制备被引导，并且还制品具有增加的生物功能如掺杂银的磷灰石31。为了制备取代的羟基磷灰石，该元件可以与相应的减少预期的元素与substitut被引入e表示， 例如 ，在钙化合物的量减少时锶，镁或锌置换尝试32。可替代地，另一种方法可以是与提供"掺杂"离子是存在的羟基磷灰石的表面上，而不必有意的元件替换到HA晶格31的意图添加元素。对于这些修改的方法是可能的制备混合溶液，例如氢氧化钙和硝酸银，并作为此处所描述的进行该反应的相同方法。 总之，本文报道了仿生羟基磷灰石的制备新颖快速和基本上改进方法。对于这种方法，化学品的快速混合时间不超过5秒，这是在时间上的显着减少相比滴定反应通常需要仔细监测小时。它有在使用BIOMAT潜力巨大erial发展，由于其相对简单和低成本相比目前使用的工业磷灰石的制造方法，其中的当前商业系统的结果在长期的研究和开发时间的固有的复杂性，并大大提高了制造成本。特别是，这种新方法是优于连续流动过程或者由于显著下启动设备投资需求热液技术。

有为了提高患者的生活质量，并减少全球人口老龄化的医疗负担很大的临床需要与增强功能先进的生物材料。羟基磷灰石已广泛，由于其良好的生物相容性应用于多年医疗应用。最近，已在使用纳米级的羟基磷灰石（羟基磷灰石）的兴趣增加，特别是用于医学和牙科矿化组织再生。在骨骼和牙齿的釉质中发现的矿物是缺钙，多取代的，纳米级羟基磷灰石。生物纳米羟基磷灰石血小板的大小估计报告的50纳米×30纳米×2纳米的1维，在不成熟的骨2所述更小的结构。与此相反，在牙齿珐琅质的矿物比在长度和宽度3,4骨组织中发现的大10至100倍。合成纳米羟基磷灰石<html>可能会更好地称为仿生，而不是仿生，因为我们正在寻求翻译关于自然材料的特性与性能改进医疗技术的意见。它已被提出，仿生羟基磷灰石可以是骨骼和牙齿的组织再生应用更有利的，因为它相似于天然存在的矿物5。 有已报道以制备羟基磷灰石包括热液6，喷雾干燥7和溶胶-凝胶8技术的各种方法。这些中，湿式沉淀法被认为是用于制备羟基磷灰石的相对方便的方法。公布的羟基磷灰石湿沉淀方法一般包括一个滴定步骤混合的钙和磷的化学前体9，10，11时，裁判"&gt; 12，13，14，但是，这些方法都具有许多缺点，包括冗长和复杂的过程结合在某些情况下，与需要昂贵的设备相关联。商业生产可能更复杂，专利描述用于复杂的反应器高品质的医疗级磷灰石15的制造。尽管这样，氢氧化钙和磷酸之间的中和反应是有利的，由于副产物的缺乏有毒化学品。 加工条件和磷灰石产物的形态之间的关系已被报道用于缓慢滴定反应。具体地，对于涉及氢氧化钙和磷酸滴定方法中，升高的温度似乎赞成粒子具有低纵横比13的制备。这项工作得到了大大代扩展瓷砖等。 16谁表现出对羟基磷灰石的产品从广泛的方法的质量温度等加工条件的关系。他的结论是，普拉卡什13的湿化学沉淀法制造的高质量的产品，但应注意的是，结果是依赖于技术上的挑战和慢/混合过程。原始普拉卡什滴定步骤接管一小时。然而，更长的滴定时间可能需要要制备大批量。 为了总结，而几个因素，包括温度的影响现在已经广泛地在减少复杂性的研究，几乎没有关注已指示和相关联的执行基于滴定的方法所需要的时间。因此，这项研究的目的是探讨应用快速混合方式，以仿生纳米羟基磷灰石制造的影响，并充分characteri泽所得到的材料。如果成功的话，简单的快速混合的方式将对实验室的研究人员和业界的一致好评，其中制造成本可以不包括质量大幅减少很大的好处。

<table><tbody><tr><td>Calcium hydroxide (purity of &amp;ge; 96%)</td><td>Sigma Aldrich UK</td><td>31219</td><td>Good laboratory practise should be used at all times including the use of appropriate personal protective equipment.</td></tr><tr><td>Phosphoric acid (85%)</td><td>Sigma Aldrich UK</td><td>345245</td><td>Safety goggles and a faceshield should be used when handling this product (see safety data sheet from Sigma Aldrich for further information).</td></tr><tr><td>STOE IP X-ray diffractometer</td><td>Phillips</td><td></td><td></td></tr><tr><td>International centre for diffraction data (ICDD) PDF4+ database</td><td>International Centre for Diffraction Data</td><td></td><td></td></tr><tr><td>Holey carbon films on 300 mesh grids</td><td>Agar Scientific</td><td>S147-3H&amp;nbsp;</td><td></td></tr><tr><td>Tecnai G2 Spirit transmission electron microscope</td><td>FEI</td><td></td><td></td></tr><tr><td>Lithium tetraborate</td><td>ICPH, Malz&amp;eacute;ville, France</td><td></td><td></td></tr><tr><td>PW2440 XRF spectrometer&amp;nbsp;</td><td>Philips</td><td></td><td></td></tr><tr><td>ThermoScientific Nikolett Spectrometer</td><td>Unicam Ltd</td><td></td><td></td></tr></tbody></table>

rapid mix preparation of bioinspired nanoscale hydroxyapatite for biomedical applications

羟基磷灰石（HA）已被广泛地用作医疗陶瓷由于其良好的生物相容性和骨传导性。最近有关于使用仿生纳米羟基磷灰石（NHA）的兴趣。然而，生物磷灰石是已知的钙缺乏和碳酸取代的纳米级片状的形态。仿生羟基磷灰石具有刺激最佳骨组织再生的潜力，因为它相似骨和牙齿珐琅质矿物。许多方法目前用来制造磷灰石在实验室和商业上，涉及冗长过程和复杂的设备。因此，本研究的目的是开发一种快速，可靠的方法来制备高品质的仿生纳米羟基磷灰石。开发的快速混合方法是基于涉及氢氧化钙和磷酸的酸 - 碱反应。简言之，磷酸溶液倒入氢氧化钙溶液中，接着搅拌，洗涤和干燥阶段。批料的一部分混合物在1000℃在为了研究产品的高温稳定性烧结2小时。 X射线衍射分析显示成功形成的HA，其显示热分解为β-磷酸三钙的高温处理中，这是典型的钙缺乏HA之后磷酸盐。傅里叶变换红外光谱表明碳酸酯基团的在沉淀出的产品的存在。芽颗粒与50×30纳米的大致尺寸，接近生物磷灰石的尺寸低纵横比。该材料也是钙缺乏与钙:1.63 P摩尔比，这样生物学磷灰石比1.67的化学计量的HA比率低。因此，这种新方法是用于制造仿生羟基磷灰石的，克服了冗长滴定和复杂的设备需要一个可靠的和更方便的过程。所得仿生HA产品是适用于各种用途医疗和消费保健应用。

<html> X射线衍射图案（ 图2）表现出纯的HA相具有宽峰的沉淀，指示相对小的晶粒尺寸和/或无定形性质。高温烧结后，β磷酸三钙（β-TCP）检测，沿着HA的主相。的衍射峰的锐化， 即在全宽度半最大值的降低，烧结后所指示的微晶尺寸的增加。 <img alt="图2" src="/files/ftp_upload/55343/55343fig2.jpg" /> 产品图2.晶相分析。 X射线衍射（XRD）在1000℃烧结2小时未烧结纳米级的羟基磷灰石（羟基磷灰石）粉末和磷灰石粉末的图案。峰标签:▼羟基磷灰石峰，β■磷酸三钙峰。ge.jpg"目标="_空白"&gt;点击此处查看该图的放大版本。 FTIR-ATR光谱（ 图3）确认一个的HA相由特性磷酸盐和羟基频带17,18的形成。详细频带被分配如下:3750厘米-1（OH -拉伸νOH）; 1086和1022厘米-1（PO 4 3-ν3）; 962厘米-1（PO 4 3-ν1）; 630厘米-1（OH -振动δOH）; 600和570 -1（PO 4 3-ν4）。在未烧结样品的附加的峰被分配如下:约有3,400 -1（吸附水分子）为中心的宽峰; 1455和1410厘米-1（CO 3 2-ν3）; 880厘米<sup&gt; -1（CO 3 2-ν2）。在未烧结粉末观察到的吸收水和碳酸酯基团在高温烧结阶段被拆除。烧结过程也削尖这是由一个更大的高峰表现到谷底的距离羟基和磷酸盐带。 <img alt="图3" src="/files/ftp_upload/55343/55343fig3.jpg" /> 图3的产品的红外光谱。在未烧结纳米级的羟基磷灰石（羟基磷灰石）粉末和磷灰石粉末在1000℃烧结2小时的衰减全反射模式（FTIR-ATR）光谱傅里叶变换红外。 <a href="https://ecsource-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/55343/55343fig3large.jpg" target="_blank">请点击此处查看该图的放大版本。</a> 透射电镜照片（ 图4），显示出纳米级颗粒机智的形成通过30纳米50纳米ħ近似尺寸。所述颗粒具有约1.7的低纵横比（颗粒长度/颗粒宽度）。纳米产品的大小和形状相似尺寸的生物磷灰石1。 <img alt="图4" src="/files/ftp_upload/55343/55343fig4.jpg" /> 图4.产品的纳米形貌。纳米羟基磷灰石（NHA）的透射电子显微照片（TEM）采用快速混合方法在两个倍数，准备。 <a href="https://ecsource-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/55343/55343fig4large.jpg" target="_blank">请点击此处查看该图的放大版本。</a> 通过XRF（ 表1）的羟基磷灰石粉末的定量化学分析允许的钙:磷比率被计算为1.63，这比在化学计量的HA略低whicH有钙:1.67磷比例。 XRF也表现出了纳米羟基磷灰石产品的高纯度记录其他元素的只有微量。 <table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always"><tbody><tr><td> 复合 </td><td> 重量％ </td></tr><tr><td>氧化钙</td><td> 51.52 </td></tr><tr><td> P 2 O 5 </td><td> 39.89 </td></tr><tr><td>氧化镁</td><td> 0.46 </td></tr><tr><td>娜2 O </td><td> 0.13 </td></tr><tr><td> Y 2 O 3 </td><td> 0.07 </td></tr><tr><td> 的 Al 2 O 3 </td><td> 0.03 </td></tr><tr><td> SiO 2的</td><td> 0.03 </td></tr><tr><td>锰3 O 4 </td><td> 0.03 </td></tr><tr><td>的SrO </td><td> 0.02 </td></tr><tr><td> 二氧化钛</td><td> 0.01 </td></tr></tbody></table>表1.定量化学品的分析。 X射线荧光（XRF）的结果为未烧结羟基磷灰石粉末显示&gt; 99％纯度（重量）。

Watch this Scientific Journal Video about Rapid Mix Preparation of Bioinspired Nanoscale Hydroxyapatite for Biomedical Applications at JoVE.com

Rapid Mix Preparation of Bioinspired Nanoscale Hydroxyapatite for Biomedical Applications

本文介绍了高品质的仿生纳米羟基磷灰石的快速制造的新方法。该生物材料是在一个广泛的骨科，颅面外科和牙科临床应用提供创新的医疗设备制造具有重要意义。

仿生纳米羟基磷灰石的快速混合制备生物医学应用

Hydroxyapatite (HA) has been widely used as a medical ceramic due to its good biocompatibility and osteoconductivity. Recently there has been interest ...

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Nanyang Technological University

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19.1K 次观看.  University of Sheffield. 本文介绍了高品质的仿生纳米羟基磷灰石的快速制造的新方法。该生物材料是在一个广泛的骨科，颅面外科和牙科临床应用提供创新的医疗设备制造具有重要意义。 

视频: Rapid Mix Preparation of Bioinspired Nanoscale Hydroxyapatite for Biomedical Applications

Separation of Single-stranded DNA, Double-stranded DNA and RNA from an Environmental Viral Community Using Hydroxyapatite Chromatography

Viruses, particularly bacteriophages (phages), are the most numerous biological entities on Earth1,2. Viruses modulate host cell abundance and diversity, contribute to the cycling of nutrients, alter host cell phenotype, and influence the evolution of both host cell and viral communities through the lateral transfer of genes 3. Numerous studies have highlighted the staggering genetic diversity of viruses and their functional potential in a variety of natural environments. 
Metagenomic techniques have been used to study the taxonomic diversity and functional potential of complex viral assemblages whose members contain single-stranded DNA (ssDNA), double-stranded DNA (dsDNA) and RNA genotypes 4-9. Current library construction protocols used to study environmental DNA-containing or RNA-containing viruses require an initial nuclease treatment in order to remove nontargeted templates 10. However, a comprehensive understanding of the collective gene complement of the virus community and virus diversity requires knowledge of all members regardless of genome composition. Fractionation of purified nucleic acid subtypes provides an effective mechanism by which to study viral assemblages without sacrificing a subset of the community&#x2019;s genetic signature. 
Hydroxyapatite, a crystalline form of calcium phosphate, has been employed in the separation of nucleic acids, as well as proteins and microbes, since the 1960s11. By exploiting the charge interaction between the positively-charged Ca2+ ions of the hydroxyapatite and the negatively charged phosphate backbone of the nucleic acid subtypes, it is possible to preferentially elute each nucleic acid subtype independent of the others. We recently employed this strategy to independently fractionate the genomes of ssDNA, dsDNA and RNA-containing viruses in preparation of DNA sequencing 12. Here, we present a method for the fractionation and recovery of ssDNA, dsDNA and RNA viral nucleic acids from mixed viral assemblages using hydroxyapatite chromotography.

We describe an efficient method to separate single-stranded DNA, double-stranded DNA and RNA molecules from environmental viral communities. Nucleic acids are fractionated using hydroxyapatite chromatography with increasing concentrations of phosphate-containing buffers. This method permits the isolation of all viral nucleic acid types from environmental samples.

分离单链DNA，双链DNA和RNA病毒使用羟基磷灰石色谱从环境社区

Viruses, particularly bacteriophages (phages), are the most numerous biological entities on Earth1,2.  Viruses modulate host cell abundance and diversity, ...

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免疫与感染

Facile Preparation of Ultrafine Aluminum Hydroxide Particles with or without Mesoporous MCM-41 in Ambient Environments

An aqueous suspension of nanogibbsite was synthesized via the titration of aluminum aqua acid [Al(H2O)6]3+ with L-arginine to pH 4.6. Since the hydrolysis of aqueous aluminum salts is known to produce a wide array of products with a wide range of size distributions, a variety of state-of-the-art instruments (i.e., 27Al/1H NMR, FTIR, ICP-OES, TEM-EDX, XPS, XRD, and BET) were used to characterize the synthesis products and identification of byproducts. The product, which was comprised of nanoparticles (10-30 nm), was isolated using gel permeation chromatography (GPC) column technique. Fourier transform infrared (FTIR) spectroscopy and powder X-ray diffraction (PXRD) identified the purified material as the gibbsite polymorph of aluminum hydroxide. The addition of inorganic salts (e.g., NaCl) induced electrostatic destabilization of the suspension, thereby agglomerating the nanoparticles to yield Al(OH)3 precipitate with large particle sizes. By utilizing the novel synthetic method described here, Al(OH)3 was partially loaded inside the highly ordered mesoporous framework of MCM-41, with average pore dimensions of 2.7 nm, producing an aluminosilicate material with both octahedral and tetrahedral Al (Oh/Td = 1.4). The total Al content, measured using energy-dispersive X-ray spectrometry (EDX), was 11% w/w with a Si/Al molar ratio of 2.9. A comparison of bulk EDX with surface X-ray photoelectron spectroscopy (XPS) elemental analysis provided insight into the distribution of Al within the aluminosilicate material. Furthermore, a higher ratio of Si/Al was observed on the external surface (3.6) as compared to the bulk (2.9). Approximations of O/Al ratios suggest a higher concentration of Al(O)3 and Al(O)4 groups near the core and external surface, respectively. The newly developed synthesis of Al-MCM-41 yields a relatively high Al content while maintaining the integrity of the ordered silica framework and can be used for applications where hydrated or anhydrous Al2O3 nanoparticles are advantageous.

An ultrafine aluminum hydroxide nanoparticle suspension was prepared via the controlled titration of [Al(H2O)]3+ with L-arginine to pH 4.6 with and without cage-effect confinement within mesoporous channels of MCM-41.

在环境环境中制备具有或不具有介孔MCM-41的超细氢氧化铝颗粒

An aqueous suspension of nanogibbsite was synthesized via the titration of aluminum aqua acid [Al(H2O)6]3+ with L-arginine to pH 4.6. Since the hydrolysis ...

化学

Development of Amelogenin-chitosan Hydrogel for In Vitro Enamel Regrowth with a Dense Interface

Biomimetic enamel reconstruction is a significant topic in material science and dentistry as a novel approach for the treatment of dental caries or erosion. Amelogenin has been proven to be a critical protein for controlling the organized growth of apatite crystals. In this paper, we present a detailed protocol for superficial enamel reconstruction by using a novel amelogenin-chitosan hydrogel. Compared to other conventional treatments, such as topical fluoride and mouthwash, this method not only has the potential to prevent the development of dental caries but also promotes significant and durable enamel restoration. The organized enamel-like microstructure regulated by amelogenin assemblies can significantly improve the mechanical properties of etched enamel, while the dense enamel-restoration interface formed by an in situ regrowth of apatite crystals can improve the effectiveness and durability of restorations. Furthermore, chitosan hydrogel is easy to use and can suppress bacterial infection, which is the major risk factor for the occurrence of dental caries. Therefore, this biocompatible and biodegradable amelogenin-chitosan hydrogel shows promise as a biomaterial for the prevention, restoration, and treatment of defective enamel.

Development of Amelogenin-chitosan Hydrogel for In Vitro Enamel Regrowth with a Dense Interface

In this article, we describe a protocol for fabricating an amelogenin-chitosan hydrogel for superficial enamel reconstruction. Organized in situ growth of apatite crystals in the hydrogel formed a dense enamel-restoration interface, which will improve the effectiveness and durability of restorations.

釉原蛋白 - 壳聚糖水凝胶的发展<em&gt;体外</em&gt;搪瓷愈合了密集接口

Biomimetic enamel reconstruction is a significant topic in material science and dentistry as a novel approach for the treatment of dental caries or ...

生物工程

Preparation of Functional Silica Using a Bioinspired Method

The goal of the protocols described herein is to synthesize bioinspired silica materials, perform enzyme encapsulation therein, and partially or totally purify the same by acid elution. By combining sodium silicate with a polyfunctional bioinspired additive, silica is rapidly formed at ambient conditions upon neutralization. 
The effect of neutralization rate and biomolecule addition point on silica yield are investigated, and biomolecule immobilization efficiency is reported for varying addition point. In contrast to other porous silica synthesis methods, it is shown that the mild conditions required for bioinspired silica synthesis are fully compatible with the encapsulation of delicate biomolecules. Additionally, mild conditions are used across all synthesis and modification steps, making bioinspired silica a promising target for the scale-up and commercialization as both a bare material and active support medium.
The synthesis is shown to be highly sensitive to conditions, i.e., the neutralization rate and final synthesis pH, however tight control over these parameters is demonstrated through the use of auto titration methods, leading to high reproducibility in reaction progression pathway and yield. 
Therefore, bioinspired silica is an excellent active material support choice, showing versatility towards many current applications, not limited to those demonstrated here, and potency in future applications.

Here, we present a protocol to synthesize bioinspired silica materials and immobilize enzymes therein. Silica is synthesized by combining sodium silicate and an amine &#39;additive&#39;, which neutralize at a controlled rate. Material properties and function can be altered either by in situ enzyme immobilization or post-synthetic acid elution of encapsulated additives.

用 Bioinspired 法制备功能性二氧化硅

The goal of the protocols described herein is to synthesize bioinspired silica materials, perform enzyme encapsulation therein, and partially or totally ...

Distinctive Capillary Action by Micro-channels in Bone-like Templates can Enhance Recruitment of Cells for Restoration of Large Bony Defect

Without an active, thriving cell population that is well-distributed and stably anchored to the inserted template, exceptional bone regeneration does not occur. With conventional templates, the absence of internal micro-channels results in the lack of cell infiltration, distribution, and inhabitance deep inside the templates. Hence, a highly porous and uniformly interconnected trabecular-bone-like template with micro-channels (biogenic microenvironment template; BMT) has been developed to address these obstacles. The novel BMT was created by innovative concepts (capillary action) and fabricated with a sponge-template coating technique. The BMT consists of several structural components: inter-connected primary-pores (300-400 &#181;m) that mimic pores in trabecular bone, micro-channels (25-70 &#181;m) within each trabecula, and nanopores (100-400 nm) on the surface to allow cells to anchor. Moreover, the BMT has been documented by mechanical test study to have similar mechanical strength properties to those of human trabecular bone (~3.8 MPa)12.
The BMT exhibited high absorption, retention, and habitation of cells throughout the bridge-shaped (&#928;) templates (3 cm height and 4 cm length). The cells that were initially seeded into one end of the templates immediately mobilized to the other end (10 cm distance) by capillary action of the BMT on the cell media. After 4 hr, the cells homogenously occupied the entire BMT and exhibited normal cellular behavior. The capillary action accounted for the infiltration of the cells suspended in the media and the distribution (active migration) throughout the BMT. Having observed these capabilities of the BMT, we project that BMTs will absorb bone marrow cells, growth factors, and nutrients from the periphery under physiological conditions.
The BMT may resolve current limitations via rapid infiltration, homogenous distribution and inhabitance of cells in large, volumetric templates to repair massive skeletal defects.

A step-by-step generic process to create a bone-like template with engineered micro-channels is presented. High absorption and retention capabilities of the template are demonstrated by capillary action via micro-channels.

独特的毛细管作用通过微通道骨般的模板可以增强细胞的招募大骨缺损修复

Without an active, thriving cell population that is well-distributed and stably anchored to the inserted template, exceptional bone regeneration does not ...

Preparation of Thermoresponsive Nanostructured Surfaces for Tissue Engineering

Thermoresponsive poly(N-isopropylacrylamide) (PIPAAm)-immobilized surfaces for controlling cell adhesion and detachment were fabricated by the Langmuir-Schaefer method. Amphiphilic block copolymers composed of polystyrene and PIPAAm (St-IPAAms) were synthesized by reversible addition-fragmentation chain transfer (RAFT) radical polymerization. A chloroform solution of St-IPAAm molecules was gently dropped into a Langmuir-trough apparatus, and both barriers of the apparatus were moved horizontally to compress the film to regulate its density. Then, the St-IPAAm Langmuir film was horizontally transferred onto a hydrophobically modified glass substrate by a surface-fixed device. Atomic force microscopy images clearly revealed nanoscale sea-island structures on the surface. The strength, rate, and quality of cell adhesion and detachment on the prepared surface were modulated by changes in temperature across the lower critical solution temperature range of PIPAAm molecules. In addition, a two-dimensional cell structure (cell sheet) was successfully recovered on the optimized surfaces. These unique PIPAAm surfaces may be useful for controlling the strength of cell adhesion and detachment.

Nanoscaled sea-island surfaces composed of thermoresponsive block copolymers were fabricated by the Langmuir-Schaefer method for controlling spontaneous cell adhesion and detachment. Both the preparation of the surface and the adhesion and detachment of cells on the surface were visualized.

温敏纳米结构表面的组织工程准备

Thermoresponsive poly(N-isopropylacrylamide) (PIPAAm)-immobilized surfaces for controlling cell adhesion and detachment were fabricated by the ...

3D Printed Porous Cellulose Nanocomposite Hydrogel Scaffolds

This work demonstrates the use of three-dimensional (3D) printing to produce porous cubic scaffolds using cellulose nanocomposite hydrogel ink, with controlled pore structure and mechanical properties. Cellulose nanocrystals (CNCs, 69.62 wt%) based hydrogel ink with matrix (sodium alginate and gelatin) was developed and 3D printed into scaffolds with uniform and gradient pore structure (110-1,100 &#181;m). The scaffolds showed compression modulus in the range of 0.20-0.45 MPa when tested in simulated in vivo conditions (in distilled water at 37 &#176;C). The pore sizes and the compression modulus of the 3D scaffolds matched with the requirements needed for cartilage regeneration applications. This work demonstrates that the consistency of the ink can be controlled by the concentration of the precursors and porosity can be controlled by the 3D printing process and both of these factors in return defines the mechanical properties of the 3D printed porous hydrogel scaffold. This process method can therefore be used to fabricate structurally and compositionally customized scaffolds according to the specific needs of patients.&#160;

The three critical steps of this protocol are i) developing the right composition and consistency of the cellulose hydrogel ink, ii) 3D printing of scaffolds into various pore structures with good shape fidelity and dimensions and iii) demonstration of the mechanical properties in simulated body conditions for cartilage regeneration.

三维印刷多孔纤维素纳米复合水凝胶脚手架

This work demonstrates the use of three-dimensional (3D) printing to produce porous cubic scaffolds using cellulose nanocomposite hydrogel ink, with ...

Procedure for Fabricating Biofunctional Nanofibers

Electrospinning is an effective processing method for preparing nanofibers decorated with functional groups. Nanofibers decorated with functional groups may be utilized to study material-biomarker interactions i.e. act as biosensors with potential as single molecule detectors. We have developed an effective approach for preparing functional polymers where the functionality has the capacity of specifically binding with a model protein. In our model system, the functional group is 2,4-dinitrophenyl (DNP) and the protein is anti-DNP IgE (Immunoglobulin E). The functional polymer, &alpha;,&omega;-bi[2,4-dinitrophenyl caproic][poly(ethylene oxide)-b-poly(2-methoxystyrene)-b-poly(ethylene oxide)] (CDNP-PEO-P2MS-PEO-CDNP), is prepared by anionic living polymerization. The difunctional initiator utilized in the polymerization was prepared by electron transfer reaction of &alpha;-methylstyrene and potassium (mirror) metal. The 2-methoxystyrene monomer was added first to the initiator, followed by the addition of the second monomer, ethylene oxide, and finally the living polymer was terminated by methanol. The &alpha;,&omega;-dihydroxyl polymer [HO-PEO-P2MS-PEO-OH] was reacted with N-2,4-DNP-&isin;-amino caproic acid, by DCC coupling, resulting in the formation of &alpha;,&omega;-bi[2,4-dinitrophenylcaproic][poly(ethyleneoxide)-b-poly(2-methoxystyrene)-b-poly(ethylene oxide)] (CDNP-PEO-P2MS-PEO-CDNP). The polymers were characterized by FT-IR, 1H NMR and Gel Permeation Chromatography (GPC). The molecular weight distributions of the polymers were narrow (1.1-1.2) and polymers with molecular weights greater than 50,000 was used in this study. The polymers were yellow powders and soluble in tetrahydrofuran. A water soluble CDNP-PEO-P2MS-PEO-CDNP/ DMEG (dimethoxyethylene glycol) complex binds and achieves steady state binding with solution IgE within a few seconds. Higher molecular weight (water insoluble i.e. around 50,000) CDNP-PEO-P2MS-PEO-CDNP polymers, containing 1% single wall carbon nanotubes (SWCNT) were processed into electroactive nanofibers (100 nm to 500 nm in diameter) on silicon substrate. Fluorescence spectroscopy shows that anti-DNP IgE interacts with the nanofibers by binding with the DNP functional groups decorating the fibers. These observations suggest that appropriately functionalized nanofibers hold promise for developing biomarker detection device.

An efficient approach for preparing nanofibers decorated with functional groups capable of specifically interacting with proteins is described. The approach first requires the preparation of a polymer functionalized with the appropriate functional group. The functional polymer is fabricated into nanofibers by electrospinning. The effectiveness of the binding of the nanofibers with a protein is studied by confocal microscopy.

制作生物功能纳米纤维的过程

Electrospinning is an effective processing method for preparing nanofibers decorated with functional groups. Nanofibers decorated with functional groups ...

生物学

Ceramic Omnidirectional Bioprinting in Cell-Laden Suspensions for the Generation of Bone Analogs

Structurally, bone tissue is an inorganic-organic composite containing metabolically active cells embedded within a hierarchical, highly mineralized matrix. This organization is challenging to replicate due to the heterogeneous environment of bone. Ceramic omnidirectional bioprinting in cell-suspensions (COBICS) is a microgel-based bioprinting technique that uniquely replicates the mineral and cellular structure of bone. COBICS prints complex, biologically relevant constructs without the need for sacrificial support materials or harsh postprocessing steps (e.g., radiation and high-temperature sintering), which are two of the biggest challenges in the additive manufacturing of bone mimetic constructs. This technique is enabled via the freeform extrusion of a novel calcium phosphate-based ink within a gelatin-based microgel suspension. The yield-stress properties of the suspension allow deposition and support the printed bone structure. UV crosslinking and nanoprecipitation then "lock" it in place. The ability to print nanostructured bone-mimetic ceramics within cell-laden biomaterials provides spatiotemporal control over macro- and micro-architecture and facilitates the real-time fabrication of complex bone constructs in clinical settings.

This protocol describes a 3D printing technique to fabricate bone-like structures by depositing a calcium phosphate ink in a gelatin-based granular support. Printed bone analogs are deposited in freeform, with flexibility for direct harvesting of the print or crosslinking within a living cell matrix for multiphasic constructs.

用于生成骨类似物的细胞悬浮液中的陶瓷全向生物打印

Structurally, bone tissue is an inorganic-organic composite containing metabolically active cells embedded within a hierarchical, highly mineralized ...

Synthesis of Graphene-Hydroxyapatite Nanocomposites for Potential Use in Bone Tissue Engineering

Developing novel materials for bone tissue engineering is one of the most important thrust areas of nanomedicine. Several nanocomposites have been fabricated with hydroxyapatite to facilitate cell adherence, proliferation, and osteogenesis. In this study, hybrid nanocomposites were successfully developed using graphene nanoribbons (GNRs) and nanoparticles of hydroxyapatite (nHAPs), that when employed in bioactive scaffolds may potentially improve bone tissue regeneration. These nanostructures can be biocompatible. Here, two approaches were used for preparing the novel materials. In one approach, a co-functionalization strategy was used where nHAP was synthesized and conjugated to GNRs simultaneously, resulting in nanohybrids of nHAP on GNR surfaces (denoted as nHAP/GNR). High-resolution transmission electron microscopy (HRTEM) confirmed that the nHAP/GNR composite is comprised of slender, thin structures of GNRs (maximum length of 1.8 &#181;m) with discrete patches (150-250 nm) of needle-like nHAP (40-50 nm in length). In the other approach, commercially available nHAP was conjugated with GNRs forming GNR-coated nHAP (denoted as GNR/nHAP) (i.e., with an opposite orientation relative to the nHAP/GNR nanohybrid). The nanohybrid formed using the latter method exhibited nHAP nanospheres with a diameter ranging from 50 nm to 70 nm covered with a network of GNRs on the surface. Energy dispersive spectra, elemental mapping, and Fourier transform infrared (FTIR) spectra confirmed the successful integration of nHAP and GNRs in both nanohybrids. Thermogravimetric analysis (TGA) indicated that the loss at elevated heating temperatures due to the presence of GNRs was 0.5% and 0.98% for GNR/nHAP and nHAP/GNR, respectively. The nHAP-GNR nanohybrids with opposite orientations represent significant materials for use in bioactive scaffolds to potentially promote cellular functions for improving bone tissue engineering applications.

Novel nanocomposites of graphene nanoribbons and hydroxyapatite nanoparticles were prepared using solution-phase synthesis. These hybrids when employed in bioactive scaffolds can exhibit potential applications in tissue engineering and bone regeneration.

仿生纳米羟基磷灰石的快速混合制备生物医学应用

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