一机能磁性纳米纤维素的细菌与氧化铁纳米粒子的制备
Summary
Here, we present a protocol to make a bacterial nanocellulose (BNC) magnetic for applications in damaged blood vessel reconstruction. The BNC was synthesized by G. xylinus strain. On the other hand, magnetization of the BNC was realized through in situ precipitation of Fe2+ and Fe3+ ferrous ions inside the BNC mesh.
Abstract
在这项研究中，由细菌Gluconacetobacter xylinus产生细菌纳米纤维素（BNC）合成并在使用氧化铁纳米颗粒（IONP） 铁 （Fe 3 O 4） 原位浸渍，得到磁性细菌纳米纤维素（MBNC）。 MBNC的合成是一个精确而专门设计的多步骤过程。简言之，将细菌纳米纤维素（BNC）药膜是从保留G形成根据我们的尺寸和形态的实验要求xylinus菌株。铁（III），氯化六水合物（的FeCl 3·6H 2 O）和铁（II），氯化四水合物（的FeCl 2·4H 2 O）与2的溶液：1的摩尔比制备，并在脱氧的高纯度的水稀释。通过BNC防护膜，然后在与反应物的容器中引入的。此混合物搅拌并在硅油浴中和氢氧化铵（14％），在80℃下加热，然后加入通过丢弃以沉淀亚铁离子进入BNC网格。最后一步允许在原地的磁性纳米颗粒铁 （Fe 3 O 4）细菌的纳米纤维素网内部形成赋予磁特性BNC薄膜。毒理学测定用来评估BNC-IONP防护膜的生物相容性。聚乙二醇（PEG）被用来覆盖IONPs以改善其生物相容性。扫描电子显微镜（SEM）图像显示，IONP被优先位于原纤维交织在BNC矩阵的空间，但它们中的一些也沿BNC色带找到。在MBNC进行磁力显微镜测量检测存在磁畴拥有高强度弱磁场，确认MBNC薄膜的磁性质。在这项工作中获得的杨氏模量也都在这些报道的几个血管在以往的研究一个合理的协议。
Introduction
所述bacterian纳米纤维素（BNC）由木醋杆菌菌株，也称为Gluconacetobacter xylinus合成，并且静置培养期间沉积在空气-液体界面上的薄膜或药膜的形式。这些BNC药膜采用在那里它们被生长的容器的形式，并且它们的厚度取决于天在培养数。A. xylinus通过聚合和随后的结晶的方法使用在用于纤维素微纤丝的合成培养基中的葡萄糖。葡萄糖残基的聚合是在细菌细胞外膜，其中葡聚糖链从分布在细胞被膜单个细孔挤出进行。纤维素微纤维的结晶发生在与通过范德华键合形成葡聚糖链片材随后通过氢键1堆叠片材的胞外空间。
磁铁集成到一个BNC矩阵集成电路纳米颗粒可容易地通过外部磁场，以增加包含磁性纳米粒子需要引导和限制平滑肌细胞的力（平滑肌细胞），在动脉壁的损伤部位进行操作。这种策略保持平滑肌远离其它组织，并保持细胞在抵抗由血液流动所施加的力的地方。它已经显示，平滑肌细胞在血管，在那里形成主要位于中膜2丰富层的vasoelasticity发挥重要的作用。
用于MBNC的合成方法涉及的BNC薄膜浸入并在80℃下铁（III）六水合氯化铁（Ⅱ）四水合氯化的溶液中搅拌。加入氢氧化铵以形成在BNC网格内的氧化铁纳米颗粒。加入氢氧化铵的变化从橙色到黑色的溶液的颜色。该IONPs紧凑沿着BNC纤维一起s的一个非均匀分布。
此协议的重点是细菌纳米纤维素磁性纳米颗粒薄膜，这是我们命名磁性细菌纳米纤维素（MBNC），它的目的是为丢失，损坏或损伤的小直径的血管的替代物使用的设计。 HS Barud和同事最近发表了类似的工作通过在PEG和超顺磁性氧化铁纳米微粒3的稳定的水性分散体混合的BNC药膜，以产生一个基于BNC柔性磁性纸。这里，我们描述了生产细菌纤维素和其就地与磁性纳米颗粒浸渍。基于检测单个DNA链断裂的细胞毒性测定用于测试的BNC和MBNC药膜的生物相容性。
Protocol
Representative Results
Discussion
在BNC防护膜的厚度和尺寸可以通过改变培养时间和其所静态培养中生长的烧瓶的尺寸来容易地操纵。在BNC的microproperties，如孔隙率，可以通过在静态培养改变氧气比修改。高浓度的氧气产生更严厉的BNC 11。 A.布丹和同事制作了一个爆破压力BNC的直径达880毫米汞柱通过在G的发酵过程中改变从大气中的氧气到100％氧气的氧气比率xylinus 12。同样地，在BNC的孔隙率，也可通?…
Disclosures
The authors have nothing to disclose.
Acknowledgements
This work was funded by Department of Defense under contract No. W81XWH-11-2-0067
Materials
| Glucoacetobacter Xylinus | ATCC | 700178 | |
| Agar | Sigma Aldrich | A1296-500G | |
| D-Mannitol Bioxtra | Sigma Aldrich | M9546-250G | |
| Yeast Extract | BD Biosciences | 212750 | |
| Bacteriological Peptone | Sigma Aldrich | P0556 | |
| Sodium Hydroxide, 50% Solution In Water | Sigma Aldrich | 158127-100G | |
| Iron(III) Chloride Hexahydrate | Sigma Aldrich | 236489-100G | |
| Ammonium Hydroxide | Macron Fine Chemicals | 6665-46 | |
| Poly(Ethylene Glycol), Average Mn 400 | Sigma Aldrich | 202398-250G | |
| Iron (II) chloride tetrahydrate | Sigma Aldrich | 44939-250G | |
| Disposable petri dish | Sigma Aldrich | BR452000 | |
| Disposable Inoculating Loop | Fisher Scientific | 22-363-604 | |
| Anhydrous Calcium Sulfate | W.A. Hammond Drierite | 13001 | |
| High vacuum grease | Sigma Aldrich | Z273554-1EA | |
| Laboratory pipetting needle with 90° blunt ends | Sigma Aldrich | CAD7937-12EA | |
| pH test strips | Sigma Aldrich | P4786-100EA | |
| Round-bottom three neck angle type distilling flask | Sigma-Aldrich | CLS4965250 | |
| Silicone oil for oil baths | Sigma-Aldrich | 85409-250ML | |
| Drying Tube | Chemglass | CG-1295-01 | |
| Septum Stopper, Sleeve Type | Chemglass | CG-3022-98 | |
| Magnetic stir bar | Chemglass | CG-2001-05 | |
| Condenser | Chemglass | CG-1218-01 | |
| Temperature Controller | BriskHeat | SDC120JC-A | |
| Stirring Hotplate | Fisher Scientific | 11-100-49SH | |
| Comet Assay Kit | Trevigen | 4250-050-K | |
| SYBR Gold Nucleic Acid Gel Stain | Life Technologies | S-11494 | |
| bio-AFM | JPK Instruments | NanoWizard 4a BioScience AFM | |
| Nanoindenter | Micro Materials Ltd | Multi-module mechanical tester | |
| Scanning electron microscopy (SEM) | Hitachi High Technologies America | Hitachi S-4800 | |
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