Mixed C18 and C1 modification on an optical fiber for chromatographic sensing

An optical fiber-chromatographic sensor, aiming at simultaneous and selective response to multiple components following a chromatographic separation, is described. We report an improved approach for immobilization of octadecyl (C(18)) and methyl (C(1)) moieties as stationary phase on an optical fiber suitable as a sensing phase for organic solutes. By this approach, the stability and lifetime of the sensing layer as well as the detectability and retention behavior of the chromatographic sensor could be improved. Infrared spectroscopy was employed to confirm the presence of C(18) and C(1) moieties on the modified surface of the optical fiber. The chromatographic sensor was applied, with good sensitivity and chemical selectivity, to the simultaneous separation and detection of bromobenzene and toluene, using water as the mobile phase.     

Fluorescent Biological Label for Recognizing Human Ovarian Tumor Cells Based on Fluorescent Nanoparticles

In this paper, we report a method for recognizing human ovarian tumor(HOT) cells using fluorescent biological label based on core-shell nanoparticles. The luminescent nanoparticles were synthesized with a water-in-oil(W/O)micromulsion technique. The fluorescent silica core-shell nanoparticles modified with anti-HER2 antibody using bifunctional cross-linker glutaraldedhyde targeted the corresponding tumor antigen in the cell surface of the SKOV3 ovarian cancer cells. The specific immunoreactivity of antibody-nanoparticles with cells was characterized by laser scanning microscopy (LSM) and scanning electron microscope (SEM). The results showed that the method offered potential advantages of sensitivity and simplicity due to high binding efficiency between nanoparticles and cells and provided an alternative method for the detection of HOT.     

Transport and separation of small organic molecules through nanotubules.

An electroless plating method was applied to deposit Au onto the surfaces and the walls of pores of polycarbonate membranes to prepare gold nanotubules. The nanotubules were modified with cysteine (Cys) or with carbamidine thiocyante (Gua). The effects of modifiers and of the fine structure of organic molecules on the transport properties of those molecules through the gold nanotubules were investigated. Studies show that the hydrophilicity of modifiers and the planar structure of permeating molecules clearly affect the transport of small organic molecules in gold nanotubules. Tryptophan (Try) and vitamin B(2) (VB(2)) was cleanly separated at pH 6.8.     

空壳纳米金修饰的新型DNA传感器

利用新型材料金纳米空球, 通过层层修饰的技术, 分别将壳聚糖、空壳纳米金、L-半胱氨酸、细胞色素c以及ssDNA探针修饰到玻碳电极表面, 制备了一种新型的DNA生物传感器. 以紫外及透射电子显微镜(TEM)表征了空壳纳米金, 以循环伏安法、阻抗谱图等电化学方法研究了传感器的特性, 通过原子力显微镜方法观察了该DNA生物传感器不同层之间的形态差异. 结果表明, 该修饰电极所吸附的ssDNA探针为1.672×10^―10 mol•cm^－2. 在指示剂柔红霉素的帮助下, DNA探针可与互补的DNA进行杂交, 借此以微分脉冲伏安法测定DNA.     

A Sandwiched Biological Fluorescent Probe for the Diagnosis of Human Ovarian Tumor Based on TiO2 Nanoparticles

In this paper, we report a novel biological fluorescent probe for the diagnosis of human ovarian tumor based on sandwiched TiO₂ nanoparticles. The fluorescence nanoparticles consist of a fluorescent molecule, tetramethyl rhodamine isothiocyanate (TRITC), sandwiched between titanium dioxide (TiO₂) nanoparticles and nano-gold via reacting with each other. The antibodies HER2, labeled on the surface of the biofluorescence nanoparticles, have granted nanoparticles the privilege of aiming at peculiar tumor antigen. The specificity of antibody-nanoparticles interacting with cells was characterized by Laser Scanning Confocal Microscope. The results showed that these sandwiched nanoparticles were innocuous and stable, and the method offered potential advantages of sensitivity and simplicity due to high combing efficiency between nanoparticles and cells and provided an alternative method for the diagnosis of human ovarian tumor (HOT).     

A DNA biosensor based on graphene paste electrode modified with Prussian blue and chitosan

A chemically modified graphene paste electrode was prepared by incorporating appropriate amounts of graphene in a paste mixture, followed by electrodepositing Prussian blue (PB) and coating chitosan on the electrode surface. The electrode was able to bind ssDNA, and gave a better voltammetric response for complement DNA than did ordinary carbon paste electrodes. The response of the electrode was characterized with respect to the paste composition, immobilization time of probe DNA on the chitosan and PB modified graphene paste electrode, and the effect of 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide hydrochloride (EDC). The electrochemical behavior of PB assembled on the graphene paste electrode was investigated. The combination of graphene and PB can enhance the current response of the graphene paste electrode. As a consequence of DNA hybridization, a significant change in the current due to daunomycin intercalated with double-stranded DNA (ds-DNA) on the surface of the graphene paste electrode was observed.     

Sensitive mediator-free tyrosinase biosensor for the determination of 2,4-dichlorophenol

Microchimica Acta - A novel tyrosinase-based biosensor was developed for the determination of 2,4-dichlorophenol (2,4-DCP) by immobilizing tyrosinase on multi-walled carbon nanotubules (MWNTs) and...     

Sensor for traces of hydrogen peroxide using an electrode modified by multiwalled carbon nanotubes, a gold-chitosan colloid, and Prussian blue

An electrochemical sensor for trace levels of hydrogen peroxide (HP) was fabricated by the self-assembly of multi-walled carbon nanotubes, a gold-chitosan colloid, followed by electrodeposition of Prussian blue. The electrode was characterized by cyclic voltammetry, electrochemical impedance spectroscopy and other methods. The electrode shows well-defined peaks at 101 mV and 193 mV, the reduction current is linearly related to the concentration of HP in the range from 4.0 to and 19.6 μM. The detection limit of 3.36 μM (at an S/N of 3).     

对氨基苯基卟啉镍聚合膜电极电催化测定对乙酰氨基酚

用电化学方法在玻碳电极表面制备了对氨基苯基卟啉镍聚合膜．采用循环伏安法，交流阻抗分析等方法研究了电极的电化学特性．在ＮａＯＨ底液中，聚合膜电极有一对稳定的氧化还原峰，能催化对乙酰氨基酚的电氧化．催化电流与对乙酰氨基酚的浓度在１×１０－６～２×１０－４ｍｏｌ·Ｌ－１范围内呈线性关系．电极用于扑热息痛片中对乙酰氨基酚含量的测定，结果令人满意．     

聚萘胺膜与金属离子的络合及催化特性的研究

系统研究了聚萘胺膜与Ａｇ、Ｈｇ（２＋）等十余种金属离子的络合特性。以循环伏安法、交流阻抗分析等方法研究了Ａｇ－ＰＮＡ电极对抗坏血酸（Ｈ２Ａ）氧化的催化作用，提出了电极反应的可能机理。Ａｇ－ＰＮＡ电极可用于测定试样中的Ｈ２Ａ含量。