<Emphasis Type="Italic">In situ</Emphasis> probing of cell–cell communications with surface-enhanced Raman scattering (SERS) nanoprobes and microfluidic networks for screening of immunotherapeutic drugs

Discovering novel drugs for cancer immunotherapy requires a robust in vitro drug screening platform that allows for straightforward probing of cell-cell communications.Here,we combined surface-enhanced Raman scattering (SERS) nanoprobes with microfluidic networks to monitor in situ the cancer-immune system intercellular communications.The microfluidic platform links up immune cells with cancer cells,where the cancer-cell secretions act as signaling mediators.First,gold@silver core-shell nanorods were employed to fabricate SERS immunoprobes for analysis of the signaling molecules.Multiple cancer secretions in a tumor microenvironment were quantitatively analyzed by a SERS-assisted three-dimensional (3D) barcode immunoassay with high sensitivity (1 ng/mL).Second,in an on-chip cell proliferation assay,multiple immunosuppressive proteins secreted by cancer cells were found to inhibit activation of immune cells,indicating that the platform simulates the physiological process of cancer-immune system communications.Furthermore,potential drug candidates were tested on this platform.A quantitative SERS immunoassay was performed to evaluate drug efficacy at regulating the secretion behavior of cancer cells and the activity of immune cells.This assay showed the suitability of this platform for in vitro drug screening.It is expected that the fully integrated and highly automated SERS-microfluidic platform will become a powerful analytical tool for probing intercellular communications and should accelerate the discovery and clinical validation of novel drugs.     

AuNRs@ZIF-8的制备及其表面增强拉曼散射光谱研究

表面增强拉曼光谱(Surface enhanced Raman spectroscopy, SERS)是一种分子光谱,具有快速、高灵敏和指纹识别的特性,在分析化学、生物医学等领域有着重要的应用。然而,在溶液样品中一些检测分子很难被SERS基底所吸附,导致分子拉曼信号增强困难。为此,本文提出了一种ZIF-8材料包覆金纳米棒(AuNRs)的核壳结构(AuNRs@ZIF-8)来实现拉曼信号增强,既可利用金纳米颗粒的表面等离激元增强特性,又可利用ZIF-8这种多孔MOFs材料的吸附性能,从而实现溶液样品的高灵敏拉曼检测。我们首先采用晶种法制备了均一性良好的AuNRs,然后对其进行聚乙烯吡咯烷酮(PVP)修饰,最后加入金属有机框架ZIF-8前驱体,得到AuNRs@ZIF-8核壳纳米结构。该结构对罗丹明(R6G)的SERS检测灵敏度很高,检测限可低至10⁻⁹ mol/L,并且线性关系和均一性均良好。此外,我们通过测试该结构吸收R6G前后的UV-Vis吸收光谱进一步证实了核壳纳米结构的生成和对目标分子的有效吸附。     

纳米结构苯胺/吡咯共聚物的静态法合成及自组装

采用静态聚合法,以过硫酸铵为氧化剂,使苯胺与吡咯进行共聚,制备了高产率(88%)的纳米结构苯胺/吡咯(PANPY)共聚物。研究结果发现,苯胺/吡咯摩尔比和聚合介质对共聚物的形貌有重大影响。以1.0 mol/L盐酸溶液为介质,苯胺/吡咯摩尔比为90/10时,可制得直径为70 nm～90 nm、长为1.3μm的共聚物纳米纤维;苯胺/吡咯摩尔比为50/50时,得到平均粒径约为400 nm的杨梅球状共聚物颗粒,透射电子显微镜的结果表明这些杨梅球状共聚物颗粒是由直径为5nm,长25nm的共聚物微小纳米纤维自组装而成。而以0.1 mol/L NaOH水溶液为反应介质,则可以得到外直径为1.8μm～2.6μm的自组装共聚物微球。     

The effect of some heat treatment parameters on the dimensional stability of AISI D2

The tool steel AISI D2 is usually processed by vacuum hardening followed by multiple tempering cycles. It has been suggested that a deep cold treatment in between the hardening and tempering processes could reduce processing time and improve the final properties and dimensional stability. Hardened blocks were then subjected to various combinations of single and multiple tempering steps (520 and 540 °C) and deep cold treatments (−90, −120 and −150 °C). The greatest dimensional stability was achieved by deep cold treatments at the lowest temperature used and was independent of the deep cold treatment time.     

Numerical study on optical properties of Ag/SiO2SiO2/Ag sandwich nanocrescents substrate

A novel structure of a metal/dielectric/metal (Ag/SiO₂SiO₂/Ag) sandwich nanocrescent has been proposed and studied. We make a detailed numerical analysis on the extinction efficiency and LSPR property of the sandwich nanocrescent by using the finite difference time domain (FDTD) method. It clearly demonstrates that a comparable field enhancement can be achieved by varying the thickness of the SiO₂SiO₂ layer at different incident polarizations. Excited in the Y-polarization, the maximum electric field enhancement factor reaches 600 at the peak wavelength 1108.9?nm, which is six times higher than previous reported single layer nanocrescent. The refractive index sensitivity of this new sandwich nanocrescent is 375.5?nm/RIU (refractive index unit). The structure is shown to produce a high local field enhancement as well as wide plasmon resonance tunabilities. Besides, compared with adjusting the shape and size of the single layer nanocrescent structure, it is much more convenient and easier to change the thickness of the sandwich nanocrescent. Due to its excellent properties, this structure is very suitable for LSPR and SERS nanosensing substrate.     

Observation and control of temperature instabilities in a four-valve pulse tube refrigerator

The use of a pulse tube cryocooler in an application requires temperature stability at the cold end. In our four-valve pulse tube refrigerator we have observed long-term temperature instabilities lasting some days and short-term instabilities lasting some hours or even minutes. Investigations have shown that the latter anomaly is caused by the dc-flow. The negative influence on the stability is due to an additional mass flow (dc-flow) to the cold end of the pulse tube, which results in a parasitic heat input.In this paper we present an actively controlled dc-flow suppression device, which uses a temperature gradient in the regenerator as a control parameter. This device enables us to eliminate the temperature instabilities.     

聚（3,4乙烯二氧噻吩）/氧化石墨烯纳米杂化结构薄膜的设计合成与电致变色性能研究

本文成功地将聚 (3, 4乙烯二氧噻吩) (PEDOT) 纳米颗粒修饰在氧化石墨烯 (GO) 纳米片表面, 获得了PEDOT/GO杂化纳米结构。采用场发射扫描电子显微镜、透射电子显微镜、拉曼光谱仪和X射线光电子能谱对杂化结构的形貌、微观结构、振动能级特征和表面化学状态进行了表征和分析。电化学性能与光吸收性能测试表明, 与PEDOT薄膜相比PEDOT/GO杂化结构的电致变色性能获得了显著的提高, PEDOT/GO杂化结构在480 nm处的着色态和褪色态之间的对比度由杂化之前的23.4%提高到了杂化后37.6%, 着色时间和褪色时间分别由1800 ms和1500 ms缩短为600 ms和700 ms, 着色效率则由杂化前的55.8 cm²/C提高至杂化后的83.4 cm²/C。研究表明PEDOT/GO杂化结构在发展新型电致变色材料方面具有很大的潜力, 在智能窗、可见光隐身材料等领域有望获得广泛的应用。     

Au/Si-NPA复合纳米体系的SERS增强能力研究

利用具有准周期结构的硅纳米孔柱阵列(silicon nanoprous pillar array,Si-NPA)为衬底使用浸渍法制备优化Au/Si-NPA活性基底。并利用最优化制备的Au/Si-NPA活性基底对罗丹明6G(Rhoda-mine 6G,R6G)进行探测,研究其表面增强拉曼散射(surface enhanced Raman scattering,SERS)光谱并对其增强原理进行解释。     

Surface-enhanced Raman scattering inside Au@Ag core/shell nanorods

The design and synthesis of plasmonic nanoparticles with Raman-active molecules embedded inside them are of significant interest for sensing and imaging applications.However,direct synthesis of such nanostructures with controllable shape,size,and plasmonic properties remains extremely challenging.Here we report on the preparation of uniform Au@Ag core/shell nanorods with controllable Ag shells of 1 to 25 nm in thickness.1,4-Aminothiophenol (4-ATP) molecules,used as the Raman reporters,were located between the Au core and the Ag shell.Successful embedding of reporter molecules inside the core/shell nanoparticles was confirmed by the absence of selective oxidation of the amino groups,as measured by Raman spectroscopy.The dependence of Raman intensity on the location of the reporter molecules in the inside and outside of the nanorods was studied.The molecules in the interior showed strong and uniform Raman intensity,at least an order of magnitude higher than that of the molecules on the nanoparticle surface.In contrast to the usual surface-functionalized Raman tags,aggregation and clustering of nanoparticles with embedded molecules decreased the surface-enhanced Raman scattering (SERS) signal.The findings from this study provide the basis for a novel detection technique of low analyte concentration utilizing the high SERS response of molecules inside the core/shell metal nanostructures.As an example,we show robust SERS detection of thiram fungicide as low as 10-9 M in solutions.     

Tunable and highly reproducible surface-enhanced Raman scattering substrates made from large-scale nanoparticle arrays based on periodically poled LiNbO3 templates

Abstract

This work describes novel surface-enhanced Raman scattering (SERS) substrates based on ferroelectric periodically poled LiNbO₃ templates. The templates comprise silver nanoparticles (AgNPs), the size and position of which are tailored by ferroelectric lithography. The substrate has uniform and large sampling areas that show SERS effective with excellent signal reproducibility, for which the fabrication protocol is advantageous in its simplicity. We demonstrate ferroelectric-based SERS substrates with particle sizes ranging from 30 to 70 nm and present tunable SERS effect from Raman active 4-mercaptopyridine molecules attached to AgNPs when excited by a laser source at 514 nm.