近年来, 金纳米粒子(AuNPs)因其极高的消光系数以及距离依赖性颜色而被广泛用于比色传感器的开发利用。 常见的盐诱导AuNPs聚集通过电荷屏蔽的方式进行, 聚集过程易受到干扰, 聚集后颜色往往不稳定, 而DNA染料通过电荷中和的方式实现AuNPs聚集, 该方法具有用量少, 聚集速度快, 并且稳定性好的优势, 因此对常见DNA染料进行筛选十分必要。 系统筛选了8种常见DNA染料包括EB、 AO、 TO、 SG、 PG、 TOTO-1、 TOTO-3和YOYO用于诱导AuNPs的快速聚集。 实验发现诱导AuNPs团聚的染料用量在0.18~2.6 μmol·L-1之间, 相比NaCl和Cys用量分别为60和20 mmol·L-1的传统诱导聚集方法用量仅为万分之一。 通过考察DNA染料诱导AuNPs聚集的“IC50”值(即诱导剂使AuNPs聚集的最大吸光度变化(A680/A520)的50%的浓度)评价聚集效率, 在筛选的8种DNA染料中, SG、 PG、 TOTO-1、 TOTO-3和 YOYO分子的“IC50”值在0.12~0.30 μmol·L-1之间, 相对较小, 诱导AuNPs聚集效率高。 由于带正电的N原子数量对AuNPs的聚集有关键性的作用, 即带正电的N原子数量越多, 中和AuNPs时的用量越少。 通过Marvin View中microspecies(微观结构式)和microspecies distribution(微观结构式分布)算出了具体带正电的N原子个数, 结果表明, 在pH=7条件下, SG、 PG、 TOTO-1、 TOTO-3和 YOYO分子带正电荷的N原子较多, 因此上述染料诱导AuNPs聚集效率高。 通过乔布曲线(Job)计算出双链DNA(dsDNA)碱基对与DNA染料的结合比, 结果表明相同条件下, 筛选的8种DNA染料与dsDNA碱基对的结合比相差不大。 结合实验拟合曲线计算出dsDNA与DNA染料的结合常数, 计算表明SG, YOYO, TOTO-3, PG与dsDNA的结合常数较大, 在2.75×109~3.12×1010 L·mol-1之间, 与DNA结合能力较强。 综合考虑SG、 PG、 YOYO、 TOTO-3等染料在快速诱导AuNPs聚集及比色传感方面效果较好。

金纳米粒子具有较大光吸收截面和光谱选择性, 在激光点火含能材料中具有极大的应用潜力。本文根据目前实验中所制备的纳米金属复合炸药的结构和尺寸, 构建了三种复合炸药的光吸收模型, 分别为Au核RDX壳球形纳米粒子, Au-RDX-Au-RDX均匀相间的球形纳米粒子, 以及RDX核Au壳的纳米粒子。利用离散偶极近似方法(DDA)对纳米金复合炸药的近红外吸收光谱进行了分析, 并考虑了多种模型核壳尺寸及周围环境介质对光吸收性质的影响。获得了近红外光辐照下, 纳米复合结构的最佳结构尺寸参数。结果表明, 当制备成纳米级Au核RDX壳球形粒子时, 其对近红外光(800 nm)波长具有较高的光吸收, 相应的核壳尺寸约为60 nm和20 nm左右, 且在水中的吸收要比在空气中的吸收强。

基于金纳米颗粒薄膜基底和金纳米棒薄膜基底，使用表面增强拉曼光谱（SERS）技术对环丙沙星（CIP）的含量进行了分析检测，为食品中CIP残留检测提供了新方法。通过使用柠檬酸钠还原氯金酸制备金纳米颗粒胶体，以及通过晶种生长法制备金纳米棒胶体，以应用于SERS增强基底。通过不同激发光波长对CIP进行SERS检测，确定了最佳激光波长为780 nm。使用校正集CIP标准溶液，建立CIP浓度-SERS信号强度的工作曲线，使用检验集样本观察工作曲线的预测能力。结果表明：使用金纳米颗粒基底进行CIP的SERS检测，回收率在97.1%~105.0%；使用金纳米棒基底进行SERS检测，回收率在96.3%~121.8%。因此，SERS在检测CIP抗生素领域具有高灵敏度、快速检测等优势。

为了解决目前水中纳米塑料颗粒难以富集和检测的问题，基于金（Au）纳米粒子和聚苯乙烯（PS）纳米粒子的混合流体，使用自搭建的光操控-显微拉曼系统实现了PS纳米粒子的光热效应捕获和检测，并研究了混合流体中PS纳米粒子的光热效应及表面增强拉曼散射（SERS）信号增强效果。结果显示，PS纳米粒子（80 nm）的运动速度受到金纳米粒子粒径和浓度的影响，随着时间的增加光热阱中会形成直径为30 μm的Au-PS聚集体。PS纳米粒子的SERS信号强度在聚集体内比金溶胶基底提高了7倍，并且密度随着聚集体半径的扩展先增加后减小。该方法实现大量PS纳米粒子的光热效应捕获和SERS检测，显著提高PS纳米粒子的SERS信号强度并且降低了检测限。该方法在纳米器件自组装、环境污染监测等方面具有极大的应用潜力。

山药是一种富含多种物质的中药材，确保山药的安全使用具有重要的意义。使用Gaussview/Gaussian09w软件对农药倍硫磷、三唑磷和福美双进行理论计算，结合农药标准溶液的表面增强拉曼光谱（SERS），确定了三种农药的拉曼特征峰。利用自组装共聚焦显微拉曼光谱仪，以金纳米溶胶作为SERS的增强基底，对中药材山药中倍硫磷、三唑磷、福美双农药残留进行了研究。实验优化了待测农药、盐酸、金溶胶粒子体积配比。实验结果表明：倍硫磷农药的拉曼谱峰带在717，1050，1221 cm^-1附近，最低检测限达到1 mg?L^-1，且在5~15 mg?L^-1范围内的拉曼峰强度与倍硫磷浓度的线性度（R）为0.9762；三唑磷的拉曼谱峰带在611，978，1001，1321，1408，1597 cm^-1附近，最低检测限达到1 mg?L^-1，在5~9 mg?L^-1范围内的R为0.9087；福美双的拉曼谱峰带在556，865，1146，1506 cm^-1附近，最低检测限达到0.1 mg?L^-1，且在0~20 mg?L^-1范围内的R为0.9905。以金纳米溶胶作为SERS增强基底的拉曼光谱检测技术有望实现对中药中农药残留的现场快速检测。

Solid-state nanopores with controllable pore size and morphology have huge application potential. However, it has been very challenging to process sub-10 nm silicon nanopore arrays with high efficiency and high quality at low cost. In this study, a method combining metal-assisted chemical etching and machine learning is proposed to fabricate sub-10 nm nanopore arrays on silicon wafers with various dopant types and concentrations. Through a SVM algorithm, the relationship between the nanopore structures and the fabrication conditions, including the etching solution, etching time, dopant type, and concentration, was modeled and experimentally verified. Based on this, a processing parameter window for generating regular nanopore arrays on silicon wafers with variable doping types and concentrations was obtained. The proposed machine-learning-assisted etching method will provide a feasible and economical way to process high-quality silicon nanopores, nanostructures, and devices. Supplementary material for this article is available online

The ascorbic acid (AA) is a biomarker that can be used to detect the symptoms of severe disorders such as scurvy, Parkinson’s, Alzheimer’s, and cardiovascular diseases. In this work, a simple and effective sensor model is developed to diagnose the presence of AA samples. To develop the sensor, a tapered single-mode optical fiber has been used with the well-known phenomenon of localized surface plasmon resonance (LSPR). For LSPR, the tapered region is immobilized with synthesized gold nanoparticles (AuNPs) and zinc oxide nanoparticles (ZnO-NPs) whose absorbance peak wavelengths appear at 519 nm and 370 nm, respectively. On the basis of nanoparticles (NPs) configurations, two different biosensor probes are developed. In the first one, the sensing region is immobilized with AuNPs and named Probe I. In the second probe, the immobilized layer of AuNPs is further coated with a layer of ZnO-NPs, and a resultant probe is termed as Probe II. The characterizations of synthesized AuNPs and developed fiber probes are done by the ultraviolet-visible (UV-vis) spectrophotometer, high-resolution transmission electron microscope (HR-TEM), atomic force microscopy (AFM), and scanning electron microscope (SEM). To enhance the selectivity, a sensing region of probes is functionalized with ascorbate oxidase enzyme that oxidizes the AA in the presence of oxygen. The response of developed sensor probes is authenticated by sensing the samples of AA in the range from 500 nM to 1 mM, which covers the range of AA found in human bodies, i.e., 40 μM – 120 μM. The performance analysis of the developed sensor probes has been done in terms of their stability, reproducibility, reusability, and selectivity. To observe the stability of AA, a pH-test has also been done that results in a better solubility of AA molecules in phosphate-buffered saline (PBS) solution.

Surface-enhanced Raman scattering (SERS) spectroscopy is presented as a sensitive and speci fic molecular tool for clinical diagnosis and prognosis monitoring of various diseases including cancer. In order for clinical application of SERS technique, an ideal method of bulk synthesis of SERS nanoparticles is necessary to obtain sensitive, stable and highly reproducible Raman signals. In this contribution, we determined the ideal conditions for bulk synthesis of Raman reporter (Ra) molecules embedded silver-gold core-shell nanoparticles (Au@Ra@ AgNPs) using hydroquinone as reducing agent of silver nitrate. By using UV-Vis spectroscopy, Raman spectroscopy and transmission electron microscopy (TEM), we found that a 2:1 ratio of silver nitrate to hydroquinone is ideal for a uniform silver coating with a strong and stable Raman signal. Through stability testing of the optimized Au@Ra@AgNPs over a two-week period, these SERS nanotags were found to be stable with minimal signal change occurred. The stability of antibody linked SERS nanotags is also crucial for cancer and disease diagnosis, thus, we further conjugated the as-prepared SERS nanotags with anti-EpCAM antibody, in which the stability of bioconjugated SERS nanotags was tested over eight days. Both UV-Vis and SERS spectroscopy showed stable absorption and Raman signals on the anti-EpCAM conjugated SERS nanotags, indicating the great potential of the synthesized SERS nanotags for future applications which require large, reproducible and uniform quantities in order for cancer biomarker diagnosis and monitoring.