金纳米材料光学传感快速检测方法研究要点初探

基于金纳米材料光学性能优良、稳定性高以及易于表面功能化等特点而建立的纳米金光学传感检测方法,具有灵敏度高、准确、易操作、可视化和成本低等优点.金纳米材料类传感器是利用功能化纳米金与目标物之间发生相互作用,使得金纳米颗粒的尺寸、形状和聚集状态发生改变,从而引起溶液颜色、荧光和散射强度发生变化,为目标物的快速检测提供了出色的测定平台.为更好地介绍金纳米材料在现代检测领域的重要作用,本文首先总结了近年来出现的四种常见纳米金光学传感检测方法:纳米金聚集光学传感法、纳米金刻蚀光学传感法、纳米金荧光光学传感法、纳米金散射光学传感法.通过介绍这些方法的检测原理,探讨了其在化学、生物和环境领域的发展及应用.随后,通过分析四种策略的设计思路,初步总结出七个关于开发纳米金光学传感检测技术实验要点,分别是纳米金的合成与表面功能化、溶液pH、反应温度和反应时间、选择性、体系检出限、方法准确性、体系可重复利用性.通过详尽分析这些要点的重要性,为接下来从事相关领域研究的科研工作者提供实验设计思路和经验.最后,本文还探讨了目前基于纳米金光学传感检测方法所面临的一些主要挑战,并展望了该类方法在未来的发展方向.例如,通过将该类方法与智能手机、层析试纸条等技术相结合,实现检测过程的简单化、便携化.总体来说,基于金纳米材料的光学传感检测方法具有良好的发展前景.     

纳米金的化学制备方法及其在生物医学领域的应用

纳米金由于具有独特的理化性质及良好的生物亲和效应,在生物医学领域,如生物标记、生物检测等方面具有重要的潜在应用价值。本文概述了纳米金的化学制备方法及其在生物医学领域的应用。     

树形大分子与金纳米颗粒复合体系构型与结合强度的分子动力学研究

通过在PAMAM型树形大分子上搭载不同尺寸的金纳米颗粒构建树形大分子-金纳米颗粒复合体系,采用经典分子动力学方法考察了金纳米颗粒尺寸、搭载数量及树形大分子聚乙二醇化修饰对复合体系构型、结合强度及在水中扩散系数的影响。结果表明,PAMAM型树形大分子经过聚乙二醇化修饰可负载更多的金纳米颗粒,使得有效包埋金纳米颗粒的同时自身尺寸未产生明显膨胀。研究结果为探索新型多功能造影剂在生物医药领域的应用具有重要意义。     

微乳法制备纳米金及其生物电催化性能研究

纳米金具有特殊的电催化性能。采用水/AOT(2-乙基己基琥珀酸酯磺酸钠)/环己烷微乳体系制备纳米金颗粒,通过改变水与AOT的物质的量比(ω)制备不同尺寸的纳米金,并通过透射电镜、紫外分光光度计、电化学工作站对纳米金颗粒的形貌尺寸、紫外吸收光谱、电化学性能进行分析与研究。结果表明,纳米金呈球形,尺寸均一,单分散性较好。通过对纳米金颗粒电催化析氢性能的测试发现,纳米金粒子分散性较好,形成的是均相溶液,纳米金粒子与Pt/C相比电催化性能稍弱,但是与纳米银、金铁合金和纳米硒化钨相比都显现出较好的电催化活性,说明纳米金粒子具有比较优良的电催化性能,为纳米金颗粒在生物电催化领域的应用奠定理论基础。     

纳米二氧化铈制备和应用研究进展

目的 通过比较各类纳米二氧化铈制备方法的优缺点,总结纳米二氧化铈在食品生物化学检测、催化与燃料电池等领域的应用研究,以促进纳米CeO2的发展,并为其应用提供参考.方法 对比分析纳米二氧化铈的制备方法,包括水热合成法、沉淀法、溶剂热法、溶胶-凝胶法、微乳液法和电化学沉积法.阐述纳米CeO2在催化(催化甲苯、CO和NOx、光催化)、食品生物化学检测(抗坏血酸、葡萄糖、黄嘌呤检测等)、燃料电池、食品包装等领域中的应用.结果 通常采用水热合成法制备纳米CeO2.纳米CeO2负载贵金属可制备生物检测催化剂及燃料电池阳极催化剂;纳米CeO2复合金属氧化物可用于制备抗紫外功能的食品包装.结论 纳米CeO2在食品生物化学检测、催化与燃料电池等领域有广阔的研究空间.     

金属纳米颗粒在表面等离激元共振生物传感器上的应用

文章研究不同形状和长径比的金属纳米颗粒应用在表面等离激元共振（SPR）生物传感器中对传感信号的影响,自制金属纳米颗粒并进行物理表征,以金纳米颗粒与抗兔IgG进行生物偶联,利用自制角度检测型SPR生物传感器对兔IgG抗体进行检测,结果表明,金属颗粒的形状和长径比对SPR传感器的共振角都有影响,金纳米棒能够明显提高SPR生物传感器的检测灵敏度。     

纳米金与生物分子的相互作用及生物传感检测

系统地分析了纳米金与生物分子的相互作用,并从光学比色分析、荧光分析、电化学检测、质量变化检测等几个方面入手,详细介绍了纳米金在DNA检测领域中的应用。     

一种在硅材料表面组装金纳米颗粒的新方法

以氯金酸、L-半胱氨酸为反应试剂,利用内电流和金硫自组装效应,在硅材料表面组装了较为均一的金纳米颗粒,并利用荧光分析与硅纳米线场效应晶体管对该方法进行了相关验证.结果表明:经氢氟酸处理后的硅材料,在氯金酸和L_半胱氨酸混合溶液中反应3 min可在硅表面得到较为均匀、稳定的金纳米颗粒层,其中,氯金酸浓度为0.5mmol/L,氯金酸和L-半耽氨酸浓度比为3∶1.荧光分析表明该方法组装的金颗粒表面已氨基功能化,使得金纳米颗粒修饰的硅材料在应用于生物检测时可直接醛基化修饰蛋白,简化了实验操作,同时,该方法可以在硅纳米线场效应晶体管中特异性组装金纳米颗粒,有力地支持了相关器件在疾病检测方面的应用.     

一种在硅材料表面组装金纳米颗粒的新方法

以氯金酸、L-半胱氨酸为反应试剂,利用内电流和金硫自组装效应,在硅材料表面组装了较为均一的金纳米颗粒,并利用荧光分析与硅纳米线场效应晶体管对该方法进行了相关验证。结果表明:经氢氟酸处理后的硅材料,在氯金酸和L-半胱氨酸混合溶液中反应3min可在硅表面得到较为均匀、稳定的金纳米颗粒层,其中,氯金酸浓度为0.5mmol/L,氯金酸和L-半胱氨酸浓度比为3∶1。荧光分析表明该方法组装的金颗粒表面已氨基功能化,使得金纳米颗粒修饰的硅材料在应用于生物检测时可直接醛基化修饰蛋白,简化了实验操作。同时,该方法可以在硅纳米线场效应晶体管中特异性组装金纳米颗粒,有力地支持了相关器件在疾病检测方面的应用。     

纳米金属颗粒的湿化学制备

纳米金属颗粒在光电子、磁性材料和器件上具有表面增强Raman效应,量子点效应和高密度存储等重要特性.综述了在光电子、磁性材料和器件有着应用前景的金、银、铜、钴、镍、铋等金属纳米颗粒的湿化学制备,探讨了金属纳米颗粒湿化学制备控制颗粒大小、形状的一些因素和一般性特点,为制备颗粒大小、形状可控的其它种类的金属纳米颗粒作参考.     

Fluoroimmunoassay for antigen based on fluorescence quenching signal of gold nanoparticles

A unique, sensitive, and highly specific fluoroimmunoassay system for antigen detection using gold and magnetic nanoparticles has been developed. The assay is based on the fluorescence quenching of fluorescein isothiocyanate caused by gold nanoparticles coated with monoclonal antibody. To demonstrate its analytical capabilities, the magnetic nanoparticles were coated with anti-alpha-fetoprotein polyclonal antibodies, which specifically bound with alpha-fetoprotein. Gold nanoparticles coated with anti-alpha-fetoprotein monoclonal antibodies could sandwich the alpha-fetoprotein captured by the magnetic nanoparticle probes. The sandwich-type immunocomplex was formed on the surface of magnetic nanoparticles and could be separated by a magnetic field. The supernatant liquid, which contained the unbound gold nanoparticle probes, was used to quench the fluorescence, and the fluorescence intensity of fluorescein isothiocyanate at 516 nm was proportional to the alpha-fetoprotein concentration. The result showed that the limit of detection of alpha-fetoprotein was 0.17 nM. This new system can be extended to detect target molecules with matched antibodies and has broad potential applications in immunoassay and disease diagnosis.     

The surface chemistry and stability of gold nanoparticles prepared using methanol extract of Eucalyptus camaldulensis

The development of nontoxic, clean techniques for synthesising metal nanoparticles such as gold has attracted increasing attention in recent years. Many reports have been published about the synthesis of gold nanoparticles using plant extracts. However, the stability of these prepared gold nanoparticles has not been investigated. In this research, the stability of gold nanoparticles prepared by Eucalyptus camaldulensis was investigated at different temperatures (4°C, 25°C and 45°C) for 8 weeks. Transmission electron microscopy and visible absorption spectroscopy confirmed the stability of gold nanoparticles during the storage period at the mentioned condition. In addition, Fourier transform–infrared spectroscopy was used to investigate the surface chemistry of gold nanoparticles prepared by the methanol extract of E. camaldulsis. The carboxyl group was characterised on the surface of the gold nanoparticles, and this functional group may have a critical role in the stability of gold nanoparticles prepared by the mentioned plant extract at different conditions. This functional group can be used for drug delivery of amino derivative drugs using gold nanoparticles.     

Colorimetric biosensing using smart materials

In recent years, colorimetric biosensing has attracted much attention because of its low cost, simplicity, and practicality. Since color changes can be read out by the naked eye, colorimetric biosensing does not require expensive or sophisticated instrumentation and may be applied to field analysis and point-of-care diagnosis. For transformation of the detection events into color changes, a number of smart materials have been developed, including gold nanoparticles, magnetic nanoparticles, cerium oxide nanoparticles, carbon nanotubes, graphene oxide, and conjugated polymers. Here, we focus on recent developments in colorimetric biosensing using these smart materials. Along with introducing the mechanisms of color changes based on different smart materials, we concentrate on the design of biosensing assays and their potential applications in biomedical diagnosis and environmental monitoring.     

Paper-based tuberculosis diagnostic devices with colorimetric gold nanoparticles

Abstract

A colorimetric sensing strategy employing gold nanoparticles and a paper assay platform has been developed for tuberculosis diagnosis. Unmodified gold nanoparticles and single-stranded detection oligonucleotides are used to achieve rapid diagnosis without complicated and time-consuming thiolated or other surface-modified probe preparation processes. To eliminate the use of sophisticated equipment for data analysis, the color variance for multiple detection results was simultaneously collected and concentrated on cellulose paper with the data readout transmitted for cloud computing via a smartphone. The results show that the 2.6 nM tuberculosis mycobacterium target sequences extracted from patients can easily be detected, and the turnaround time after the human DNA is extracted from clinical samples was approximately 1 h.     

Gold nanoparticles: a revival in precious metal administration to patients

Gold has been used as a therapeutic agent to treat a wide variety of rheumatic diseases including psoriatic arthritis, juvenile arthritis, and discoid lupus erythematosus. Although the use of gold has been largely superseded by newer drugs, gold nanoparticles are being used effectively in laboratory based clinical diagnostic methods while concurrently showing great promise in vivo either as a diagnostic imaging agent or a therapeutic agent. For these reasons, gold nanoparticles are therefore well placed to enter mainstream clinical practice in the near future. Hence, the present review summarizes the chemistry, pharmacokinetics, biodistribution, metabolism, and toxicity of bulk gold in humans based on decades of clinical observation and experiments in which gold was used to treat patients with rheumatoid arthritis. The beneficial attributes of gold nanoparticles, such as their ease of synthesis, functionalization, and shape control are also highlighted demonstrating why gold nanoparticles are an attractive target for further development and optimization. The importance of controlling the size and shape of gold nanoparticles to minimize any potential toxic side effects is also discussed.     

Quantification of proteins on gold nanoparticles by combining MALDI-TOF MS and proteolysis

Protein-coated nanoparticles have been used in many studies, including those related to drug delivery, disease diagnosis, therapeutics, and bioassays. The number and density of proteins on the particles' surface are important parameters that need to be calculable in most applications. While quantification methods for two-dimensional surface-bound proteins are commonly found, only a few methods for the quantification of proteins on three-dimensional surfaces such as nanoparticles have been reported. In this paper, we report on a new method of quantifying proteins on nanoparticles using matrix assisted laser desorption/ionization time of flight (MALDI-TOF) mass spectrometry (MS). In this method, the nanoparticle-bound proteins are digested by trypsin and the resulting peptide fragments are analyzed by MALDI-TOF MS after the addition of an isotope-labeled internal standard (IS) which has the same sequence as a reference peptide of the surface-bound protein. Comparing the mass intensities between the reference peptide and the IS allows the absolute quantification of proteins on nanoparticles, because they have the same molecular milieu. As a model system, gold nanoparticles were examined using bovine serum albumin (BSA) as a coating protein. We believe that our strategy will be a useful tool that can provide researchers with quantitative information about the proteins on surfaces of three-dimensional materials.     

Applications of Gold Nanoparticles in the Detection and Identification of Infectious Diseases and Biothreats

The situation of infectious diseases and biothreats all over the world remains serious. The effective identification of such diseases plays a very important role. In recent years, gold nanoparticles have been widely used in biosensor design to improve the performance for the detection of infectious diseases and biothreats. Here, recent advances of gold‐nanoparticle‐based biosensors in this field are summarized.     

Time-dependent, protein-directed growth of gold nanoparticles within a single crystal of lysozyme

Gold nanoparticles are useful in biomedical applications due to their distinct optical properties and high chemical stability. Reports of the biogenic formation of gold colloids from gold complexes has also led to an increased level of interest in the biomineralization of gold. However, the mechanism responsible for biomolecule-directed gold nanoparticle formation remains unclear due to the lack of structural information about biological systems and the fast kinetics of biomimetic chemical systems in solution. Here we show that intact single crystals of lysozyme can be used to study the time-dependent, protein-directed growth of gold nanoparticles. The protein crystals slow down the growth of the gold nanoparticles, allowing detailed kinetic studies to be carried out, and permit a three-dimensional structural characterization that would be difficult to achieve in solution. Furthermore, we show that additional chemical species can be used to fine-tune the growth rate of the gold nanoparticles.     

Nucleic acid detection strategy using gold nanoprobe of two diverse origin

In recent years, nanoparticles especially with gold and silver nanoparticles based point of care diagnostic methods is being developed for the lethal diseases like dengue. This study focused to work on the dengue virus detection in a simplest method using gold nanoparticles probe (AuNPs) with thiol tagged single strand DNA (ss‐DNA). A sensitive, fluorescence‐based detection strategy was designed to examine and quantified the hybridisation process and also elucidated the behaviour of AuNPs before and after interaction of biomolecule. The detection process was focused on aggregation of gold nanoprobe in the presence of complementary strand (target region). Hence the percentage of aggregation was measured and as a result, the limit of detection was found to be 10⁻⁶ dilutions. Current detection method was highly sensitive, easy to perform and the reaction timing is rapid between 5 and 10 min, and it can be observed through naked eye.Inspec keywords: patient diagnosis, microorganisms, nanomedicine, gold, fluorescence, nanosensors, DNA, nanoparticles, molecular biophysics, diseases, optical sensorsOther keywords: nucleic acid detection strategy, gold nanoprobe, silver nanoparticles, lethal diseases, dengue virus detection, gold nanoparticles probe, thiol tagged single strand DNA, hybridisation process, detection process, aggregation, complementary strand, current detection method, point‐of‐care diagnostic methods, fluorescence‐based detection strategy, Au     

Doping and alloying in atomically precise gold nanoparticles

The recent success in the synthesis and total structure determination of atomically precise gold nanoparticles has provided exciting opportunities for fundamental studies as well as the development of new applications. These unique nanoparticles are of molecular purity and possess well defined formulas （i.e., specific numbers of metal atoms and ligands）, resembling organic compounds. Crystallization of such molecularly pure nanoparticles into macroscopic single crystals allows for the determination of total structures of nanoparticles （i.e., the arrangement of metal core atoms and surface ligands） by X-ray crystallography. In this perspective article, we summarize recent efforts in doping and alloying gold nanoparticles with other metals, including Pd, Pt, Ag and Cu. With atomically precise gold nanoparticles, a specific number of foreign atoms （e.g., Pd, Pt） can be incorporated into the gold core, whereas a range of Ag and Cu substitutions is observed but, interestingly, the total number of metal atoms in the homogold nanoparticle is preserved. The heteroatom substitution of gold nanoparticles allows one to probe the optical, structural, and electronic properties truly at the single-atom level, and thus provides a wealth of information for understanding the intriguing properties of this new class of nanomaterials.