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。     

纳米多孔光波导漏模共振传感器的折射率灵敏度分析(英文)

在玻璃基片上射频溅射50 nm厚的金膜,然后利用TiO2胶体溶液在金膜表面制备了厚度约为320 nm的TiO2纳米多孔薄膜.以此双层膜为漏模光波导芯片,构建了基于Kretschmann结构的波长调制型光波导漏模共振(LMR)传感器.利用扫描电子显微镜(SEM)观测了TiO2纳米多孔薄膜的表面和横截面形貌.实验研究了在纳米多孔光波导中给定漏模的共振波长及折射率灵敏度与入射角的依赖关系.结果表明,随着入射角的增大,共振波长逐渐蓝移,折射率灵敏度随之下降.此外,与传统的表面等离子体共振(SPR)传感器进行了对比,结果表明在相同的共振波长下,纳米多孔光波导LMR传感器折射率灵敏度大于SPR传感器.     

基于壳聚糖-纳米金粒子的生物传感器的构造与应用研究进展

对近年来基于壳聚糖-纳米金粒子的生物传感器的构造与应用研究进行了回顾与总结.在结合纳米金粒子独特的物理化学特性和壳聚糖良好的生物相容性,壳聚糖与酶及纳米金粒子等良好的结合能力特性基础上,通过不断改进电极结构,使用层-层复合技术以及添加碳纳米管或纳米金丝的方法,能构造出具有很高灵敏度和检测极限的纳米复合材料生物传感器.通过改变结合酶的品种,可以获得具有不同检测环境和检测物质适应性的生物传感器.对生物传感器的应用也进行了相应的总结.     

基于金基纳米粒子修饰的生物传感器研究进展

重点介绍了金铂、金银等合金纳米粒子在修饰过氧化氢生物传感器、免疫生物传感器、葡萄糖生物传感器及DNA生物传感器中的应用.金基合金纳米粒子修饰的生物传感器对降低过电位、促进电子传递、提高检测灵敏度和选择性以及保持生物酶活性具有良好的效果.展望了金基纳米粒子在生物传感器领域应用的发展前景.     

化学工业中的纳米技术(续)

四、纳米传感器在纳米技术中的独特地位　　纳米传感器(nanosensors)作为一种传感和响应极小物理量的“元件”,将使生物和化学物质,移位和行动,力和物质,声音、热和电磁刺激的检测发生一场革命性的变化。本文主要介绍纳米传感器开发近况,着重说明纳米材料、纳米粒子和纳米元件(特别是纳米管)在生物技术,化学和气体方面的应用。因为纳米传感器产品商品化情况尚不清楚,故很难预测其产值。按FrostandSullivan计划,以纳米技术为基础的检测器,生物传感器和测量变换器在2 0 0 7年前可能达到工业应用水平。纳米技术将对化学工业产生巨大影响,但是…     

用于新型冠状病毒检测的纳米材料及生物传感技术

新型冠状病毒肺炎(Corona Virus Disease 2019, COVID-19)疫情大流行引起全球对此重大突发公共卫生事件的高度关注。新型冠状病毒(SARS-CoV-2)经过多次突变,出现传染速度加快、免疫逃逸、隐匿性传播等特性,令防控形势至今仍异常严峻。对患者的早发现、早隔离仍然是目前最有效的防控措施。因此,迫切需要快速、高灵敏的检测手段来甄别此病毒,以便及早识别感染者。本文简要介绍了SARS-CoV-2的一般特征,并针对核酸、抗体、抗原及病原体作为检测靶标的不同检测手段及最新进展进行分类概述;对一些光学、电学、磁学以及可视化的新型纳米传感器在SARS-CoV-2检测技术上的应用进行了分析。鉴于纳米技术的应用在提高检测灵敏度、特异性以及准确率上具有优势,本文详细介绍了新型纳米传感器在SARS-CoV-2检测中的研究进展,包括表面增强拉曼基生物传感器、电化学生物传感器、磁纳米生物传感器以及比色生物传感器等,并探讨了纳米材料在新型生物传感器构建中的作用和挑战,为纳米材料研究人员开发各种类型的冠状病毒传感技术提供思路。     

金纳米线的制备及传感应用研究进展

金纳米材料除了具有普通纳米材料的特性(表面效应、介电限域效应、小尺寸效应及量子隧道效应等)外,还具备独特的稳定性、导电性,优良的生物相容性以及超分子和分子识别、荧光等特性,这使其在纳米电子学、光电子学、传感和催化、生物分子标记、生物传感等领域展现出广阔的应用前景。在多种形态各异的金纳米材料中,金纳米线一直受到研究者们的高度重视。探索制备金纳米线的新技术与新方法,进一步拓展其应用领域,是当前纳米材料领域的研究焦点之一。金纳米线因具有长径比大、柔性较高以及制备方法简便等优点,在传感器、微电子、光学器件、表面增强拉曼、生物检测等领域都展现出不可忽视的潜力。随着技术的发展,研究者们已开发了多种制备金纳米线的方法,如模板合成法、溶液法、阶边修饰法。然而近年来,纳米电子学与传感器等领域的应用需求对金纳米线的制备方法提出了更高的要求,如制备的金纳米线要有较为理想的形貌(金纳米线的直径与几何结构直接影响电子的传输性能),且要考虑方法的复杂性,是否对环境造成污染及金纳米线产量等因素。本文结合近十年来金纳米线的制备与应用研究成果,重新分类归纳了金纳米线的制备方法与调控方式,并对金纳米线在传感领域的应用进行了较为全面的总结,以期为后续研究提供参考。     

纳米材料过氧化物模拟酶在比色分析及电化学传感器中的应用

纳米材料模拟酶与天然酶相比,稳定性好,反应活性较高,易于对各类功能分子或蛋白质等进行修饰和标记,能够方便地应用于生物分析检测中.近几年,国内外的研究人员制备出各种各样的新型纳米材料模拟酶用于过氧化氢、葡萄糖、癌症标志物的检测.简要总结了近年来国内外磁性纳米粒子、金属纳米粒子、纳米合金等纳米材料模拟酶在比色分析及电化学传感器中应用的研究进展.     

基于表面等离子共振的油品种类检测方法

针对油品顺序输送中混油界面的鉴定问题,提出了一种利用表面等离子共振(SPR)技术检测油品种类的方法.论文选取90#汽油、93#汽油、97#汽油作为测量对象,根据不同油品介电常数的差异,通过检测不同油品流经SPR传感器表面后,引起的SPR共振角的变化,获得了不同油品的折射率.实验结果表明,SPR技术能够识别不同的油品种类,测量结果准确可靠,为今后在线、快速、精确的混油检测奠定了技术基础.     

分子印迹纳米材料研究进展

概括分子印迹技术、纳米材料、分子印迹纳米材料研究状况;概述沉淀聚合法、表面分子印迹法、溶胶-凝胶聚合法、原位聚合法、磁性纳米粒子聚合法等分子印迹纳米材料合成方法;总结分子印迹纳米材料在样品前处理及色谱检测和纳米分子印迹传感器方面的应用。认为纳米技术和分子印迹技术相结合,可打破传统分子印迹聚合物的缺陷和不足,赋予分子印迹纳米材料良好的选择特异性、更高的结合能力、高的灵敏度和更快的结合动力学特性,在蛋白质、血液、传感器等方面会有广泛的应用。提出对纳米结构分子印迹材料进行研究须解决的问题。     

Label-free biosensing by surface plasmon resonance of nanoparticles on glass: optimization of nanoparticle size

The unique optical properties of noble metal nanoparticles have been used to design a label-free biosensor in a chip format. In this paper, we demonstrate that the size of gold nanoparticles significantly affects the sensitivity of the biosensor. Gold nanoparticles with diameters in the range of 12-48 nm were synthesized in solution and sensor chips were fabricated by chemisorption of these nanoparticles on amine-functionalized glass. Sensors fabricated from 39-nm-diameter gold nanoparticles exhibited maximum sensitivity to the change of the bulk refractive index and the largest "analytical volume", defined as the region around the nanoparticle within which a change in refractive index causes a change in the optical properties of the immobilized nanoparticles. The detection limit for streptavidin-biotin binding of a sensor fabricated from 39-nm-diameter nanoparticles was 20-fold better than a previously reported sensor fabricated from 13-nm-diameter gold nanoparticles. We also discuss several other factors that could improve the performance of the next generation of these immobilized metal nanoparticle sensors.     

Nanoparticle-enhanced surface plasmon resonance detection of proteins at attomolar concentrations: comparing different nanoparticle shapes and sizes

The application of biofunctionalized nanoparticles possessing various shapes and sizes for the enhanced surface plasmon resonance (SPR) detection of a protein biomarker at attomolar concentrations is described. Three different gold nanoparticle shapes (cubic cages, rods and quasi-spherical) with each possessing at least one dimension in the 40-50 nm range were systematically compared. Each nanoparticle (NP) was covalently functionalized with an antibody (anti-thrombin) and used as part of a sandwich assay in conjunction with a Au SPR chip modified with a DNA-aptamer probe specific to thrombin. The concentration of each NP-antibody conjugate solution was first optimized prior to establishing that the quasi-spherical nanoparticles resulted in the greatest enhancement in sensitivity with the detection of thrombin at concentrations as low as 1 aM. When nanorod and nanocage antibody conjugates were instead used, the minimum target concentrations detected were 10 aM (rods) and 1 fM (cages). This is a significant improvement (>10(3)) on previous NP-enhanced SPR studies utilizing smaller (~15 nm) gold NP conjugates and is attributed to the functionalization of both the NP and chip surfaces resulting in low nonspecific adsorption as well as a combination of density increases and plasmonic coupling inducing large shifts in the local refractive index at the chip surface upon nanoparticle adsorption.     

Quantitative methods for spatially resolved adsorption/desorption measurements in real time by surface plasmon resonance microscopy

A simple method for converting local reflectivity changes measured in surface plasmon resonance (SPR) microscopy to effective adlayer thicknesses and absolute surface coverages of adsorbed species is presented. For a range of high-contrast angles near the SPR resonance where the local metal surface's reflectivity changes linearly with angle, the change in reflectivity at fixed angle is proportional to the change in effective refractive index (eta(eff)) near the surface. This change in eta(eff) can be converted to absolute adsorbate coverage using methods developed for quantitative SPR spectroscopy. A measurement of the change in reflectivity due to changes in refractive index of bulk solutions, i.e., percent reflectivity change per refractive index unit (RIU), is the only calibration required. Application of this method is demonstrated for protein adsorption onto protein/DNA arrays on gold from aqueous solution using an SPR microscope operating at 633 nm. A detection limit of 0.072% change in absolute reflectivity is found for simultaneous measurements of all 200 microm x 200 microm areas within the 24-mm(2) light beam with 1-s time averaging. This corresponds to a change in effective refractive index of 1.8 x 10(-5) and a detection limit for protein adsorption of 1.2 ng/cm(2) (approximately 0.5 pg in a 200-microm spot). The linear dynamic range is Deltaeta(eff) = approximately 0.011 RIU or approximately 720 ng/cm(2) of adsorbed protein. Using a nearby spot as a reference channel, one can correct for instrumental drift and changes in refractive index of the solutions in the flow cell.     

Surface plasmon resonance scattering and absorption of anti-EGFR antibody conjugated gold nanoparticles in cancer diagnostics: applications in oral cancer

Gold nanoparticles with unique optical properties may be useful as biosensors in living whole cells. Using a simple and inexpensive technique, we recorded surface plasmon resonance (SPR) scattering images and SPR absorption spectra from both colloidal gold nanoparticles and from gold nanoparticles conjugated to monoclonal anti-epidermal growth factor receptor (anti-EGFR) antibodies after incubation in cell cultures with a nonmalignant epithelial cell line (HaCaT) and two malignant oral epithelial cell lines (HOC 313 clone 8 and HSC 3). Colloidal gold nanoparticles are found in dispersed and aggregated forms within the cell cytoplasm and provide anatomic labeling information, but their uptake is nonspecific for malignant cells. The anti-EGFR antibody conjugated nanoparticles specifically and homogeneously bind to the surface of the cancer type cells with 600% greater affinity than to the noncancerous cells. This specific and homogeneous binding is found to give a relatively sharper SPR absorption band with a red shifted maximum compared to that observed when added to the noncancerous cells. These results suggest that SPR scattering imaging or SPR absorption spectroscopy generated from antibody conjugated gold nanoparticles can be useful in molecular biosensor techniques for the diagnosis and investigation of oral epithelial living cancer cells in vivo and in vitro.     

Magnetic nanoparticle-enhanced biosensor based on grating-coupled surface plasmon resonance

A highly sensitive surface plasmon resonance (SPR) biosensor employing magnetic nanoparticle (MNP) assays is presented. In the reported approach, MNPs simultaneously served as "vehicles" for rapid delivery of target analyte from a sample to the sensor surface and as labels increasing the measured refractive index changes that are associated with the binding of target analyte. An optical setup based on grating-coupled surface plasmon resonance (GC-SPR) was used with a magnetic field gradient applied through the sensor chip for manipulating with MNPs on its surface. Iron oxide MNPs and a sensor surface with metallic diffraction grating were modified with antibodies that specifically recognize different epitopes of the analyte of interest. The sensitivity of the biosensor was investigated as a function of mass transport of the analyte to the sensor surface driven by diffusion (free analyte) or by the magnetic field gradient (analyte bound to MNPs). Immunoassay-based detection of β human chorionic gonadotropin (βhCG) was implemented to evaluate the sensitivity of the MNP-enhanced GC-SPR biosensor scheme. The results reveal that the sensitivity of βhCG detection was improved by 4 orders of magnitude compared with the regular SPR sensor with direct detection format, and a limit of detection below pM was achieved.     

Detection of electrochemical enzymatic reactions by surface plasmon resonance measurement

We describe the surface plasmon resonance (SPR) detection of an enzymatic turnover reaction and the measurement of glucose concentration using a multienzyme layer modified gold electrode. We constructed an osmium redox polymer mediated enzyme sensor on a gold thin-film electrode and monitored electrochemical reaction by SPR measurement. Unlike the usual binding assay with SPR, here we used SPR to detect the redox state of an electron mediator that was the result of the electron-transfer reaction of sequential enzymatic reactions. Therefore, the degree of refractive index change was independent of the dielectric property of the substrate and enzymatic molecular recognition was converted to refractive index change with amplification. For the quantitative evaluation of glucose with this method, we used chronopotentiometry and a linear relation was obtained between the glucose concentration and the rate of refractive index change.     

Surface enhanced absorption and transmission from dye coated gold nanoparticles in thin films

Absorption spectra of gold nanoisland thin film and the composite film of gold having thin coating of Methylene Blue and Rh6G dyes have been studied. Thin gold nanoisland film shows surface plasmon resonance (SPR) peak in the visible wavelength range, which shifts to near infrared with an increase in the thickness of the film. It was found that thin film of gold consists of nanoparticles of different size and shape, particularly nanorods of noncylindrical shapes. A linear relation was found between SPR peak wavelength and the aspect ratio of the nanoparticles in gold thin film. Effective medium refractive index of the gold film is estimated to be ~2.5, which decreases with an increase in film thickness. The coating of dyes on gold films splits the SPR peak with an enhanced absorption. Enhancement in absorption of composite film is maximal when the dye absorption peak coincides with the SPR peak; otherwise enhancement in transmission is observed for all the wavelength range. Absorption amplitude of composite film peaks increase with an increase in the gold film thickness, which tend toward saturation for film thickness of ≥6 nm. A correlation shows that absorption spectra can be described by the Maxwell Garnett theory, when the gold nanoparticles have a nearly spherical shape for very thin film (≤6 nm).     

Surface-plasmon resonance spectrometry and characterization of absorbing liquids

The effect of absorption of the sample medium on the surface-plasmon resonance (SPR) characteristics is analyzed by approximate analytical and exact numerical models. We show that absorption leads to specific changes in the value of reflectivity near the SPR angle and that these can be used for absorbance detection. The strongest absorption-induced change in reflectivity occurs at two values of metal film thickness (28 and 55 nm for a gold film and lambda = 632.8 nm). Using a sample solution of Rhodamine 700 in ethanol, we measured the characteristic changes in the SPR angle and in reflectivity over the wavelength interval encompassing the strong absorption band at 610-680 nm. The possibility of the simultaneous determination of the refractive index and absorption from SPR measurements is demonstrated and has the potential for substance-specific detection.     

Characterization of high refractive index semiconductor films by surface plasmon resonance

Si-based surface plasmon resonance (SPR) in the Kretschmann-Raether geometry is considered as a platform for the optical measurement of high refractive index films. The implementation of the SPR effect becomes possible due to the relatively high index of refraction of Si compared to most materials. As examples we study the SPR responses for some important semiconductor-based films, including laser-ablated porous silicon and thin germanium films. Using SPR data, we determine the refractive indices of these films for different parameters (thickness and porosity) and ambiences. We also discuss novel SPR biosensor architectures with the use of these solid films.