金纳米棒基于对苯二酚合成
Summary
本文描述了金纳米棒的合成一个协议的基础上，使用氢醌作为还原剂，以及用于控制它们的尺寸和纵横比的不同的机制。
Abstract
Gold nanorods are an important kind of nanoparticles characterized by peculiar plasmonic properties. Despite their widespread use in nanotechnology, the synthetic methods for the preparation of gold nanorods are still not fully optimized. In this paper we describe a new, highly efficient, two-step protocol based on the use of hydroquinone as a mild reducing agent. Our approach allows the preparation of nanorods with a good control of size and aspect ratio (AR) simply by varying the amount of hexadecyl trimethylammonium bromide (CTAB) and silver ions (Ag+) present in the “growth solution”. By using this method, it is possible to markedly reduce the amount of CTAB, an expensive and cytotoxic reagent, necessary to obtain the elongated shape. Gold nanorods with an aspect ratio of about 3 can be obtained in the presence of just 50 mM of CTAB (versus 100 mM used in the standard protocol based on the use of ascorbic acid), while shorter gold nanorods are obtained using a concentration as low as 10 mM.
Introduction
金粒子（AuNPs）是在生物医学应用中使用最普遍的和有前途的纳米结构中的一个。其用途是在许多点现场护理体外诊断产品必不可少1他们已经提出作为许多其它不同的应用程序的有效工具：在成像研究的造影剂，2作为药物递送系统3和作为药物的光诱导热疗（或光热疗法）。4金纳米粒子的巨大潜力，带动，在过去的20年里，新合成，能够加大对规模的控制和形状而获得的发展深入研究。5这是因为，不同种类的金纳米粒子的实际上比其他为特定应用更适合。
之间的不同的金的纳米结构，金纳米棒（AuNRs）已成为最有趣的系统之一。 AuNRs的特征在于由两个疟原虫沿着纵向和横向轴线的电子的振荡关联的网卡的峰，分别6是特别重要的是，最激烈的纵向峰值的位置可以被精确调谐620之间以及800纳米，取决于棒的纵横比。这个区域中的生物窗口，7其中人组织几乎不吸收光，允许多项体内涉及金纳米粒子光子应用的发展相匹配。
尽管在这种纳米结构的巨大兴趣，对于AuNRs的制备合成方案从若干限制苦。在大多数的情况下，纳米棒根据由秀和同事开发了两步法来制备。8在它们的协议，纳米棒由减少在预制金种子，银离子和大量的存在下，使用抗坏血酸金离子合成十六烷基三甲基溴化铵（CTAB），交流ationic线性表面活性剂。
这个协议的缺点是，金离子的还原率相对较低（约20％）9和一个高量的CTAB，昂贵的试剂占大于在合成试剂的总成本的一半，是必要的。一个新的，更有效的合成路线的发展是从那里被认为是一个重要的需求，从而允许基于AuNRs生物医学方法的扩展。
在本文件的第一部分中，我们提出对于具有约三长径比制备AuNR的优化协议。的合成是基于使用氢醌作为温和的还原剂，它允许AuNR与一种几乎定量还原金离子的制备中，利用CTAB减少量的10此协议为AuNRs的制备是基于上，其中金种子在“成长溶胶中使用的两个步骤的方法ution“。
在第二部分中，我们显示了如何微调得到AuNR的尺寸和纵横比两种方式。第一种方式，类似于基于抗坏血酸的标准协议，是改变存在于“生长溶液”银离子的量。第二种方式是基于可减小到10mM的浓度（接近由供应商报告的临界胶束浓度），以获得良好定义短纳米棒的CTAB的量的变化。
Protocol
Representative Results
Discussion
这里介绍的协议适用于对苯二酚，芳香分子特征是一个弱还原电位，产生金纳米棒。有朝向基础上使用的抗坏血酸的最常用的合成路线本协议的两个主要优点：第一是，对苯二酚能够几乎定量减少金离子允许生产更高量的金纳米棒的11。后者是由它需要的CTAB较低量和成本随后大幅减少的事实给出。本协议是基于一两步方法，与从所述纳米棒的生长的成核步骤的分离涉及。我们注意到由紫?…
Disclosures
The authors have nothing to disclose.
Acknowledgements
Funding for this research was provided by the Italian Ministry of Health under the frame of EuroNanoMed II (European Innovative Research & Technological Development Projects in Nanomedicine, project title: ”InNaSERSS”).
Materials
| Gold(III) chloride trihydrate | Sigma Aldrich | 520918 | |
| Hydroquinone | Sigma Aldrich | H17902 | |
| Silver Nitrate | Sigma Aldrich | 209139 | toxic |
| Sodium Borohydride | Sigma Aldrich | 480886 | |
| Hexadecyltrimethylammonium bromide (CTAB) | Sigma Aldrich | H5882 | Acute Tox. (oral). In this study we tested three different batches of CTAB (H5882) from Sigma Aldrich. Two of them were marked as made in China while one as made in India. In our experience only the batches marked as made in China were effective for the preparation of AuNR |
| Spectrophotometer | Thermo scientific | Nanodrop 2000C | |
| TEM | JEOL | 2100 |
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