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1.
目的:将原子转移自由基聚合物(ATRP)修饰金纳米粒子(GNps)引入传统的免疫传感器,提出一种新的免疫传感器策略。方法:用ATRP反应修饰GNps,增加活性位点,提高传感器的检查灵敏度。结果:该免疫传感器能够对0.5fg/mL促肾上腺皮质激素释放激素(CRH)产生应答,线性标定范围为0.5~250fg/mL。结论:新研制的免疫传感器具有良好的选择性、重复性和稳定性。 相似文献
2.
制成了以亚甲基蓝为介体的电流型过氧化氢生物传感器,通过离子交换牢固地固定在Nafion膜中的亚甲基蓝,能有效地在辣根过氧化物酶和玻碳电极之间传递电子.探讨了pH值、温度、工作电位和抗坏血酸等物质对此传感器生物电催化还原H 2O 2的影响.此生物传感器选择性好、灵敏度高,对H 2O 2线性响应范围为5.0×10 -7~2×10 -4 mol/L,响应时间少于30 s. 相似文献
3.
A set of carbon monoxide (CO) gas sensors based on porous silicon (PSi)/gold nanoparticle (AuNP) hetro structures were fabricated. Different forms of PSi surface morphologies were studied as a substrate for growth of AuNPs. Simple dipping process of PSi in hydrogen tetrachloroaurate (III) solution (HAuCl4) at fixed concentrations of 10−2 M/3.5 HF was used to synthesize AuNPs. The n-type PSi was equipped through photo-electrochemical etching process at current density value of 10 mA/cm2 under illumination condition of 530-nm wavelength and laser illumination intensity of 20 to 80 mW/cm2. Three different forms of PSi morphology, meso, macro, and double layers with pore shapes and sizes, were prepared. The structural and surface morphology properties of PSi-based substrate before and after deposition of AuNPs were investigated through studying of scanning electron microscopy (SEM), photoluminescence (PL), and X-ray diffraction (XRD). The electrical property (J-V) was carried out in primary vacuum and CO at low pressure. The results show that PSi surface morphologies strongly influenced the AuNP sizes and hence the sensor performance. It was found that decrease the AuNP sizes could be occasioned in high and fast current response. 相似文献
4.
Gold nanostructures have very suitable physical properties for plasmonic applications but do not stick on glass substrates. One usually uses a chromium adhesion layer that gives good mechanical adhesion but quench the plasmon. We developed a new adhesion process that permits a covalent bonding between gold and glass thanks to an MPTMS molecular layer throughout nanolithography process. We demonstrate that this new adhesion layer allows an improvement of the optical properties of the gold nanoparticles as well as an essential improvement of their surface-enhanced Raman scattering performances. 相似文献
5.
A highly sensitive dual-core photonic crystal fiber based on a surface plasmon resonance (PCF-SPR) biosensor with a silver-graphene layer is described. The silver layer with a graphene coating not only prevents oxidation of the silver layer but also can improve the silver sensing performance due to the large surface-to-volume ratio of graphene. The dual-core PCF-SPR biosensor is numerically analyzed by the finite-element method (FEM). An average spectral sensitivity of 4350 nm/refractive index unit (RIU) in the sensing range between 1.39 and 1.42 and maximum spectral sensitivity of 10,000 nm/RIU in the sensing range between 1.43 and 1.46 are obtained, corresponding to a high resolution of 1 × 10−6 RIU as a biosensor. Our analysis shows that the optical spectra of the PCF-SPR biosensor can be optimized by varying the structural parameters of the structure, suggesting promising applications in biological and biochemical detection. 相似文献
6.
In pH 8.4 Tris–HCl buffer solutions, alcohol dehydrogenase catalyzed the reaction between ethanol and nicotinamide adenine dinucleotide to produce acetaldehyde. In the medium of HCl, acetaldehyde reduced HAuCl 4 to form gold particles that exhibited a strong resonance scattering (RS) peak at 600 nm. The RS peak increased with ethanol concentration. The increased RS intensity at 600 nm (Δ I 600 nm) was proportional to the ethanol concentration ( C) from 0.068 to 10.2 mmol/L, with a regression equation of Δ I 600 nm?=?35.59? C?+?16.1, and a detection limit (3 σ) of 3.2 μmol/L. This proposed method was applied to detect ethanol in saliva and plant cell culture medium samples, with satisfactory results. 相似文献
7.
Plasmonics - A highly sensitive surface plasmon resonance (SPR) sensor comprising a dual-core photonic crystal fiber (PCF) is designed to detect minute changes in analyte refractive indices (RIs)... 相似文献
9.
In this paper, a rough silver core-shell nanoparticle with strong electric field enhancement in the vicinity of a bumpy structure on the silver core-shell surface is reported. A dipolar plasmonic mode of the silver nanoshell is investigated by using the quasi-static approach and plasmon hybridization theory, which analytical results identify the electric field enhancement spectra in which the enhancement is optimized. As the silver shell thickness is small, the hot spots play an important role in the plasmonic field enhancement. In addition, the deposition of a rough silver shell can generate a stronger near-field enhancement near the silver surface which is more desirable than that of a smooth silver shell for sensitive detection based on SPR and surface enhanced Raman scattering (SERS). The plasmonic field enhancement of a bumpy silver core-shell nanoparticle permits the detection and characterization of bovine serum albumin (BSA) protein molecule and hemoglobin solution with a high sensitivity. 相似文献
10.
In the medium of H 2SO 4 and in the presence of TiO 2+, gold nanoparticles in size of 10 nm exhibited a weak surface plasmon resonance scattering (SPRS) peak at 775 nm. Upon addition
of trace H 2O 2, the yellow complex [TiO(H 2O 2)] 2+ formed that cause the gold nanoparticles aggregations to form bigger gold nanoparticle clusters in size of about 900 nm,
and the SPRS intensity at 775 nm ( I) enhanced greatly. The enhanced intensity Δ I was linear to the H 2O 2 concentration in the range of 0.025–48.7 μg/mL, with a detection limit of 0.014 μg/mL H 2O 2. This SPRS method was applied to determining H 2O 2 in water samples with satisfactory results. 相似文献
11.
Carbon nanotubes (CNTs) are often used as conductive fillers in composite materials, but electrical conductivity is limited by the maximum filler concentration that is necessary to maintain composite structures. This paper presents further improvement in electrical conductivity by precipitating gold nanoparticles onto CNTs. In our composites, the concentrations of CNTs and poly (vinyl acetate) were respectively 60 and 10 vol%. Four different gold concentrations, 0, 10, 15, or 20 vol% were used to compare the influence of the gold precipitation on electrical conductivity and thermopower of the composites. The remaining portion was occupied by poly(3,4-ethylenedioxythiophene) poly(styrenesulfonate), which de-bundled and stabilized CNTs in water during synthesis processes. The concentrations of gold nanoparticles are below the percolation threshold of similar composites. However, with 15-vol% gold, the electrical conductivity of our composites was as high as ∼6×10 5 S/m, which is at least ∼500% higher than those of similar composites as well as orders of magnitude higher than those of other polymer composites containing CNTs and gold particles. According to our analysis with a variable range hopping model, the high conductivity can be attributed to gold doping on CNT networks. Additionally, the electrical properties of composites made of different types of CNTs were also compared. 相似文献
12.
Peracetic acid is gaining usage in numerous industries who have found a myriad of uses for its antimicrobial activity. However, rapid high throughput quantitation methods for peracetic acid and hydrogen peroxide are lacking. Herein, we describe the development of a high-throughput microtiter plate based assay based upon the well known and trusted titration chemical reactions. The adaptation of these titration chemistries to rapid plate based absorbance methods for the sequential determination of hydrogen peroxide specifically and the total amount of peroxides present in solution are described. The results of these methods were compared to those of a standard titration and found to be in good agreement. Additionally, the utility of the developed method is demonstrated through the generation of degradation curves of both peracetic acid and hydrogen peroxide in a mixed solution. 相似文献
13.
In this work, we have demonstrated that the exquisite optical properties based on localized surface plasmon resonance (LSPR)
of Au 2S/AuAgS-coated gold nanorods (Au 2S/AuAgS-coated GNRs) can be utilized to develop a simple and sensitive biosensor, and goat anti-human IgG can be detected
by the human IgG probe as low as 0.2 nM. Moreover, we introduce an integrated LSPR biosensor constructed by integrating Au 2S/AuAgS-coated GNRs immobilized on glass slide and isolated Au 2S/AuAgS-coated GNRs in the form of liquid. The detection of target binding was performed via direct spectral changes induced
by changes of refractive index in the vicinity of individual particles. The integrated LSPR optical biosensor is label-free,
cost-effective, and easy to fabricate and requires only a visible/near-infrared spectrometer for detection purposes. Additionally,
the investigation on the mutual influence of the two types of nanorods in the integrated LSPR biosensor was performed. The
results of separate experiments indicate that the nanorods in the form of isolate or in integrated exhibit a similar behavior. 相似文献
14.
In the study, a new assay of vascular endothelial growth factor (VEGF) has been developed by the use of gold nanoparticles (GNPs)–anti-VEGF conjugates. The immunoreaction between GNPs–anti-VEGF conjugates and VEGF took place in pH?7.5 PBS buffer solution after the addition of VEGF. The formation of GNPs modified VEGF immunocomplex resulted in the enhanced resonance light scattering (RLS) intensity at 388.0 nm. Under the optimal conditions, the magnitude of enhanced RLS intensity (Δ I RLS) was proportional to the VEGF concentration in the range from 100 to 1,500 pg?mL ?1, with a detection limit of 60 pg?mL ?1. The surface plasma resonance absorption spectrum, the characteristics of RLS, the VEGF immunocomplex, and the optimum conditions of the immunoreaction have all been investigated. The VEGF concentrations of 20 serum specimens detected by the developed assay showed consistent results in comparison with those obtained by commercially available enzyme-linked immunosorbent assay kit. 相似文献
15.
We study an active modulation of surface plasmon resonance (SPR) of Au nanoparticles based on highly doped graphene in visible and near-infrared regions. We find that compared to the traditional metal SPR, the SPR of Au nanoparticles based on graphene causes a remarkable blue shift. The field intensity in the gap is redistributed to standing wave. The field intensity of standing wave is about one order of magnitude higher than the traditional model. Moreover, the SPR of Au nanoparticles can be actively modulated by varying the graphene Fermi energy. We find the maximum modulation of field intensity of absorption spectra is more than 21.6 % at λ?=?822?nm and the amount of blue shift is 17.4 nm, which is about 2.14 % of the initial wavelength λ 0?=?813.4?nm, with increasing monolayer graphene Fermi energy from 1.0 to 1.5 ev. We find that the SPR sensitivity to the refractive index n of the environment is about 642 nm per refractive index unit (RIU). The SPR wavelengths have a big blue shift, which is about 33 nm, with increasing number of graphene layers from 1 to 3, and some shoulders on the absorption spectra are observed in the models with multilayer graphene. Finally, we study the Au nanorod array based on monolayer graphene. We find that the blue shift caused by the graphene increases from 14 to 24 nm, with increasing gap g y from 10 to 20 nm. Then, it decreases from 24 to 14 nm, with increasing gap g y from 20 to 50 nm. This study provides a new way for actively modulating the optical and optoelectronic devices. 相似文献
16.
L-amino acid oxidase (LAAO) has important biological roles in many organisms, thus attracting great attention from researchers to establish its detection methods. In this study, a new quantitative in-gel determination of LAAO activity based on ferric-xylenol orange (Fe IIIXO) formation was established. This method showed that due to the conversion of Fe II to Fe III by H 2O 2 and subsequent formation of Fe IIIXO complex halo in agar medium, the logarithm of H 2O 2 concentration from 5 to 160 µM was linearly correlated to the diameter of purplish red Fe IIIXO halo. By extracting the LAAO-generated H 2O 2 concentration, the LAAO activity can be quantitatively determined. This Fe IIIXO agar assay is highly sensitive to detect H 2O 2 down to micromolar range. More importantly, it is easy to handle, cheap, reproducible, convenient and accurate. Coupled with SDS-PAGE, it can directly be used to determine the number and approximate molecular weight of LAAO in one assay. All these features make this in-gel Fe IIIXO assay useful and convenient as a general procedure for following enzyme purification, assaying fractions from a column, or observing changes in activity resulting from enzyme modifications, hence endowing this method with broad applications. 相似文献
17.
Under certain conditions, single-stranded DNA adsorbs to negatively charged gold nanoparticles in a colloid whereas double-stranded
DNA does not. We present evidence that this phenomenon can be explained by the difference in their electrostatic properties
that in turn reflects conformational differences. The ability to discriminate the hybridization state of DNA on the basis
of adsorption behavior can be utilized to design simple colorimetric and fluorimetric assays that take advantage of plasmon
resonance in the gold nanoparticles. We present examples where we detect specific target sequences in oligonucleotides and
in genomic DNA. Because conformational changes in special DNA sequences can also be induced by analytes such as potassium,
we report a potassium ion detection scheme based on the same principle. 相似文献
18.
The efficient evolution of hydrogen through electrocatalysis is considered a promising approach to the production of clean hydrogen fuel. Platinum (Pt)‐based materials are regarded as the most active hydrogen evolution reaction (HER) catalysts. However, the low abundance and high cost of Pt hinders the large‐scale application of these catalysts. Active, inexpensive, and earth‐abundant electrocatalysts to replace Pt‐based materials would be highly beneficial to the production of cost‐effective hydrogen energy. Herein, a novel organoimido‐derivatized heteropolyoxometalate, Mo4‐CNP, is designed as a precursor for electrocatalysts of the HER. It is demonstrated that the carbon, nitrogen, and phosphorus sources derived from the Mo4‐CNP molecules lead to in situ confined carburization, phosphorization, and chemical doping on an atomic scale, thus forming nitrogen‐doped porous molybdenum carbide and phosphide hybrids, which exhibit remarkable electrocatalytic activity for the HER. Such an organically functionalized polyoxometalate‐assisted strategy described here provides a new perspective for the development of highly active non‐noble metal electrocatalysts for hydrogen evolution. 相似文献
19.
纳米粒子在生物医学上的应用越来越广泛,其进入细胞的机制与规律是设计与开发的基础.已有研究发现,表面修饰不同亲疏水性基团的金纳米粒子,在内吞机制被抑制时,进入细胞的能力明显不同.更特别的是,粒子表面亲水性基团与疏水性基团呈间隔条纹规则排列的纳米粒子,与其他修饰成分相同仅排列不同的纳米粒子进入细胞的规律区别显著.这一特殊现象无法用已有的纳米粒子进入细胞的机制解释.本文针对该研究结果,将纳米粒子与细胞的体系简化,定量分析了3种不同纳米粒子进入细胞前后的不同状态,计算获得了表面修饰不同亲疏水性基团的纳米粒子与细胞膜之间相互作用的Flory.Huggins自由能.结果发现,修饰规则间隔排列亲疏水基团的纳米粒子,其作用自由能在与细胞接触前后变化最大.研究结果不仅解释了实验发现,同时预示了纳米粒子进入细胞的新机制. 相似文献
20.
The search for Pt‐free electrocatalysts exceeding pH‐universal hydrogen evolution reaction (HER) activities when compared to the state‐of‐the‐art commercial Pt/C is highly desirable for the development of renewable energy conversion systems but still remains a huge challenge. Here a colloidal synthesis of monodisperse Rh 2P nanoparticles with an average size of 2.8 nm and their superior catalytic activities for pH‐universal HER are reported. Significantly, the Rh 2P catalyst displays remarkable HER performance with overpotentials of 14, 30, and 38 mV to achieve 10 mA cm ?2 in 0.5 m H 2SO 4, 1.0 m KOH, and 1.0 m phosphate‐buffered saline, respectively, exceeding almost all the documented electrocatalysts, including the commercial 20 wt% Pt/C. Density functional theory calculations reveal that the introduction of P into Rh can weaken the H adsorption strength of Rh 2P to nearly zero, beneficial for boosting HER performance. 相似文献
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