Synthesis of gold nanoparticles using multifunctional peptides
Synthesis of gold nanoparticles using multifunctional peptides
复制标题
DOI：
10.1002/smll.200500172
复制
发表时间：
2005-11-01
期刊：
影响因子：
13.3
通讯作者：
Naik, RR
中科院分区：
文献类型：
--
作者：
Slocik, JM;Stone, MO;Naik, RR
利用纳米粒子的光学特性进行生物检测和成像等生物学应用越来越受到人们的关注。[1]贵金属纳米粒子由于其表面等离子体共振（SPR）而表现出独特的光学性质。银和金纳米颗粒的SPR吸收带强烈地依赖于它们的尺寸、形状和聚集。[2]由于SPR波段可以在很宽的范围内调谐，金属纳米颗粒被探索作为表面增强拉曼，[3]化学或生物传感[4]和生物成像的活性表面。[5]因此，高度期望能够合成具有受控尺寸和形状的水稳定的纳米颗粒，其可以容易地用生物分子（肽、酶、抗体、DNA）官能化。具有生物分子识别基序的纳米颗粒的稳定化和功能化为各种应用提供了灵活性，包括生物检测和混合结构的组装。[6]金纳米粒子的合成方法包括经典的柠檬酸盐还原法[7]，以及使用生物有机体[8]和烷基胺[9]，并且是金纳米粒子合成中采用的众多方法之一。在这里，我们展示了使用一个简单的一锅法合成水稳定的，单分散的金纳米粒子，其表面涂覆有生物分子识别图案。多功能肽不仅可以还原氯金酸，而且可以包覆在金纳米颗粒的表面，从而使纳米颗粒在水溶液中稳定。发现从噬菌体肽展示文库中鉴定的A3亲本十二肽（表1）与金和银表面结合。[10]A3肽含有能够通过疏水相互作用或氢键与金属表面相互作用的氨基酸。[11-13]与银表面结合，但不能还原银离子。相反，当A3肽暴露于0.5mM氯金酸（HAuCl 4）溶液时，在5分钟内形成深红色溶液（图1A中的插图）。这种颜色归因于金纳米颗粒的表面等离子体共振。使用A3肽合成的金纳米颗粒在溶液中保持悬浮数天，而使用Flg肽或其他非特异性肽合成的纳米颗粒在静置时导致纳米颗粒的团聚和沉淀。A3肽的还原能力并不出乎意料，因为它含有氨基酸酪氨酸，已知其可还原HAuCl 4。[14]例如，Flg肽，一种用于标记蛋白质的常用生物分子识别结构域[15]，含有单个酪氨酸，也能够快速还原HAuCl 4。[14]A3和Flg合成的金纳米颗粒的UV/维斯光谱分别在523和534 nm处显示出表面等离子体共振峰（图1A）。酪氨酸的固有荧光对氧化敏感，荧光的损失指示酪氨酸的酚氧基的氧化，并且可以被监测。[14]如图1B所示，A3肽的酪氨酸残基的荧光在加入HAuCl 4后5分钟内完全丧失，这与523 nm处的等离子体共振带的出现很好地相关
There is a growing interest in exploiting the optical properties of nanoparticles for biological applications such as biodetection and imaging.[1] Noble metal nanoparticles exhibit unique optical properties due to their surface plasmon resonance (SPR). The SPR absorption band of silver and gold nanoparticles is strongly dependent on their size, shape, and aggregation.[2] Since the SPR band can be tuned over a broad range, metal nanoparticles are being explored as active surfaces for surface-enhanced Raman,[3] chemical, or biological sensing,[4] and in bioimaging.[5] As a result, the ability to synthesize aqueous-stabilized nanoparticles of controlled size and shape that can be easily functionalized with biomolecules (peptides, enzymes, antibodies, DNA) is highly desirable. The stabilization and functionalization of nanoparticles with biomolecular recognition motif provides flexibility for a variety of applications, including biodetection and in the assembly of hybrid structures.[6] Methods for the synthesis of gold nanoparticles include the classic citrate reduction method,[7] as well as the use of biological organisms [8] and alkylamines,[9] and are among the numerous approaches employed in the synthesis of gold nanoparticles. Here we demonstrate the use of a simple one-pot process for synthesizing water-stabilized, monodisperse gold nanoparticles that are coated with biomolecular recognition motifs on their surfaces. The multifunctional peptides not only reduce the choloraurate but also coat the surface of the gold nanoparticles, resulting in the stabilization of the nanoparticles in aqueous solution. The A3 parent dodecapeptide (Table 1), identified from a phage peptide display library, was found to bind to both gold and silver surfaces.[10] The A3 peptide contains amino acids that are capable of interacting with metallic surfaces via hydrophobic interactions or hydrogen bonding.[11–13] It binds to silver surfaces but is incapable of reducing silver ions. In contrast, when the A3 peptide was exposed to a solution of 0.5 mm chloroauric acid (HAuCl4), an intense reddish-colored solution was formed within 5 min (inset in Figure 1A). This color is attributed to the surface plasmon resonance of gold nanoparticles. Gold nanoparticles synthesized using the A3 peptide remained suspended in solution for several days, whereas nanoparticles synthesized using the Flg peptide or other nonspecific peptides resulted in the agglomeration and precipitation of the nanoparticles upon standing. The reducing ability of the A3 peptide was not unexpected since it contains the amino acid tyrosine, which is known to reduce HAuCl4.[14] For example, the Flg peptide, a commonly used biomolecular recognition domain for tagging proteins [15] that contains a single tyrosine, is also capable of rapidly reducing HAuCl4.[14] The UV/Vis spectra of the A3-and Flg-synthesized gold nanoparticles exhibit a surface plasmon resonance peak at 523 and 534nm, respectively (Figure1A). The intrinsic fluorescence of tyrosine is sensitive to oxidation, and the loss of fluorescence indicates the oxidation of the phenoxide group of tyrosine and can be monitored.[14] As shown in Figure 1B, the fluorescence of the tyrosine residue of the A3 peptide is completely lost within five minutes after the addition of HAuCl4, and this correlates nicely with the appearance of the plasmon resonance band at 523 nm