Development of uncoated near-spherical gold nanoparticles for the label-free quantification of Lactobacillus rhamnosus GG by surface-enhanced Raman spectroscopy
Development of uncoated near-spherical gold nanoparticles for the label-free quantification of Lactobacillus rhamnosus GG by surface-enhanced Raman spectroscopy
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DOI：
10.1007/s00216-019-01938-4
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发表时间：
2019-08-01
影响因子：
4.3
通讯作者：
Bordes, Claire
中科院分区：
文献类型：
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作者：
Akanny, Elie;Bonhomme, Anne;Bordes, Claire
研究了以金纳米颗粒为基底的表面增强拉曼光谱（Sers）方法，用于益生菌的无标记检测和定量。事实上，一个简单而快速的Sers方法的发展，专门用于定量的细菌应该是非常有用的表征，这样的制剂在一个更方便的方式比通常进行繁琐和耗时的传统计数方法。为此，未涂覆的近球形金纳米粒子在室温下通过酸性处理的星形金纳米粒子前体开发。在这项研究中，我们首先研究了酸性处理条件对纳米粒子的物理化学性质和Sers效率的影响，使用罗丹明6 G（R6 G）作为“模型”分析物。结果表明，通过R6 G-阴离子相互作用促进化学效应和获得合适的纳米颗粒聚集态，可以获得有效的R6 G拉曼信号增强。根据纳米颗粒的合成条件，R6 G Sers信号比用星形金纳米颗粒获得的信号大10（2）-10（3）倍。合成的球形金纳米粒子，然后成功地应用于检测和定量的鼠李糖乳杆菌GG（LGG）。在这种情况下，信号增强特别是由于阴离子诱导的化学增强和纳米颗粒聚集在LGG细胞壁上的非特异性相互作用的组合。在30分钟内实现的程序的简单性和速度（包括纳米颗粒合成、样品制备和Sers光谱的获取）似乎与掺入益生菌的药物制剂的表征非常相关。
The Surface-enhanced Raman spectroscopy (SERS) method based on gold nanoparticles as SERS substrate was investigated for the label-free detection and quantification of probiotic bacteria that are widely used in various pharmaceutical formulations. Indeed, the development of a simple and fast SERS method dedicated to the quantification of bacteria should be very useful for the characterization of such formulations in a more convenient way than the usually performed tedious and time-consuming conventional counting method. For this purpose, uncoated near-spherical gold nanoparticles were developed at room temperature by acidic treatment of star-like gold nanoparticle precursors. In this study, we first investigated the influence of acidic treatment conditions on both the nanoparticle physicochemical properties and SERS efficiency using Rhodamine 6G (R6G) as "model" analyte. Results highlighted that an effective R6G Raman signal enhancement was obtained by promoting chemical effect through R6G-anion interactions and by obtaining a suitable aggregation state of the nanoparticles. Depending on the nanoparticle synthesis conditions, R6G SERS signals were up to 10(2)-10(3)-fold greater than those obtained with star-like gold nanoparticles. The synthesized spherical gold nanoparticles were then successfully applied for the detection and quantification of Lactobacillus rhamnosus GG (LGG). In that case, the signal enhancement was especially due to the combination of anion-induced chemical enhancement and nanoparticle aggregation on LGG cell wall consecutive to non-specific interactions. Both the simplicity and speed of the procedure, achieved under 30 min, including nanoparticle synthesis, sample preparation, and acquisition of SERS spectra, appeared as very relevant for the characterization of pharmaceutical formulations incorporating probiotics.