Development of Non-Labeled QCM Biosensor for the Detection of <i>β</i>-Galactosidase: A Comparative Study of Gold and Polystyrene Nanoparticles

The performance of gold and polystyrene nanoparticles was investigated using quartz crystal microbalance (QCM) as sensor platform;β-Galactosidase antibody with corresponding antigen was utilized for the immunoreaction. The development of the immunosensor included: 1) formation of self assembled monolayers on quartz crystals;2a) immobilization of p-aminothiophenol functionalized gold nanoparticles on carboxyl-terminated self assembled monolayer, or 2b) immobilization of polystyrene nanoparticles on crystals modified with p-aminothiophenol self assembled monolayer;3) attachment of monoclonal anti β-Gal on nanoparticles;and 4) detection of target analyte. The nanoparticles used were synthesized in house and characterized by transmission electron microscopy and infrared spectroscopy. The results revealed that antibodies were strongly attached to functionalized gold nanoparticles;the weaker immobilization of antibodies to polystyrene nanoparticles provoked their detachment during antigen detection. When cross reactivity of polystyrene nanoparticles was checked using a different antigen (Brucella), displacement of antibody was not recorded, demonstrating specificity of the reaction. To the best of our knowledge this is the first direct comparison between behaviors of biosensors developed with two commonly used nanoparticles. The results showed that both nanoparticles produced biosensors capable to detect β-Gal. Nevertheless biosensors developed using polystyrene nanoparticles are simpler, cheaper and more eco-friendly than those developed using gold nanoparticles.

Accumulation of the betaine and ectoine in osmotic stress adaptation of biocontrol agents against <i>Fusarium verticillioides</i>in maize

The aims of this study was to examine the effect of the osmotic (NaCl) water stress on, growth and accumulation of endogenous compatible solutes of Bacillus amyloliquefaciens and Microbacterium oleovorans, biocontrol agents against Fusarium verticillioides. Triptic soya broth media were modified ionically to 0.99;0.98;0.97 and 0.96 aw with NaCl. The endogenous contents of the intracellular compatible solutes glycine-betaine and ectoine were quantified. Cells grown under ionic solute stress showed accumulation of significant amounts of both amino acids in all treatments. The growth rate of F. verticillioides was decreased significantly by interaction with B. amyloliquefaciens and M. oleovorans physiologically adapted at 0.96 aw. This study have demonstrated the ability to synthesize betaine and ectoine under high-osmolality conditions of B. amyloliquefaciens and M. oleovorans cells. Such ecophysiological manipulation, especially to water stress, may increase the potential for biological control of F. verticillioides at field under wider aw conditions.

Monte Carlo方法模拟光在生物组织中传播的新进展

Monte Carlo方法已被广泛用于模拟复杂的随机介质如生物组织中光的辐射传输.在生物光子应用中,早期的Monte Carlo模拟模型忽略了光在组织中传输的波动性,而用中性粒子光子包来模拟其传播过程.然而,许多光学诊断技术是基于光在组织中的偏振效应和多重散射的相干性来揭示组织的生理和病理信息,这就要涉及光辐射的波动性.本文阐述了用Monte Carlo方法模拟光在生物组织中传播的最新进展.

Functionalized CVD monolayer graphene for label-free impedimetric biosensing

在大区域 graphene 生长的最近的进展在不同区域导致了许多应用。在现在的学习，化学蒸汽扔了(CVD ) 在玻璃底层上支持的单层 graphene 为电气化学的 biosensing 应用作为电极材料被检验。我们由在酸的水的答案在 situ 准备的 carboxyphenyl 重氮基盐的电气化学的减小为 CVD 单层 graphene 的共有原子价 functionalization 报导灵巧的策略。修改 carboxyphenyl 的 graphene 用拉曼光谱学， X 光检查光电子光谱学(XPS ) ，和原子力量被描绘显微镜学(AFM ) ，以及电气化学的阻抗光谱学(EIS ) 。我们也证明 graphene 表面上的 grafted carboxyphenyl 组的数字能被扫描为 electrografting 使用了的周期的 voltammetry (CV ) 的数字控制。我们进一步在 grafted 的激活以后在 graphene 表面上基于 ovalbumin 抗体的固定介绍 immunosensor 的制造和描述经由 EDC/NHS 化学的羧基的组。在使表面不能调动的抗体和 ovalbumin 之间的绑定然后用 Faradaic EIS 被监视在[Fe (CN )< 潜水艇 class= “ a-plus-plus ” > 6 ] 3/4 答案。费用转移抵抗的百分比变化(R < 潜水艇 class= “ a-plus-plus ” > 在绑定以后的 ct ) 为从 1.0 pg 的 ovalbumin 集中展出了线性依赖？

Barrett食管的诊断和处理

在西方成人，Barrett食管的患病率为2％，是仅次于结肠息肉的常见癌前病变之一。其中食管腺癌是最重要的并发症，终生风险在男性为5％，女性为3％。诊断Barrett食管对患者来说其影响非常复杂，牵涉到预后不确定、担忧将来演变为癌症、筛查需要重复内镜检查、药物和反复检查的费用等多方面问题。