抗原变异可使得多种致病微生物易于逃避宿主免疫应答。表达在感染红细胞表面的恶性疟原虫红细胞表面蛋白1（PfPMP1）与感染红细胞、内皮细胞、树突状细胞以及胎盘的单个或多个受体作用，在黏附及免疫逃避中起关键的作用。每个单倍体基因组var基因家族编码约60种成员，通过启动转录不同的var基因变异体为抗原变异提供了分子基础。

疟原虫var基因转换速率变化导致抗原变异[英]／Paul H, Robert P, Christodoulou Z, et al//Proc Natl Acad Sci U S A

Detection of chemical and biological agents plays a fundamental role in biomedical, forensic and environmental sciences1–4 as well as in anti bioterrorism applications.5–7 The development of highly sensitive, cost effective, miniature sensors is therefore in high demand which requires advanced technology coupled with fundamental knowledge in chemistry, biology and material sciences.8–13

In general, sensors feature two functional components: a recognition element to provide selective/specific binding with the target analytes and a transducer component for signaling the binding event. An efficient sensor relies heavily on these two essential components for the recognition process in terms of response time, signal to noise (S/N) ratio, selectivity and limits of detection (LOD).14,15 Therefore, designing sensors with higher efficacy depends on the development of novel materials to improve both the recognition and transduction processes. Nanomaterials feature unique physicochemical properties that can be of great utility in creating new recognition and transduction processes for chemical and biological sensors15–27 as well as improving the S/N ratio by miniaturization of the sensor elements.28

Gold nanoparticles (AuNPs) possess distinct physical and chemical attributes that make them excellent scaffolds for the fabrication of novel chemical and biological sensors (Figure 1).29–36 First, AuNPs can be synthesized in a straightforward manner and can be made highly stable. Second, they possess unique optoelectronic properties. Third, they provide high surface-to-volume ratio with excellent biocompatibility using appropriate ligands.30 Fourth, these properties of AuNPs can be readily tuned varying their size, shape and the surrounding chemical environment. For example, the binding event between recognition element and the analyte can alter physicochemical properties of transducer AuNPs, such as plasmon resonance absorption, conductivity, redox behavior, etc. that in turn can generate a detectable response signal. Finally, AuNPs offer a suitable platform for multi-functionalization with a wide range of organic or biological ligands for the selective binding and detection of small molecules and biological targets.30–32,36 Each of these attributes of AuNPs has allowed researchers to develop novel sensing strategies with improved sensitivity, stability and selectivity. In the last decade of research, the advent of AuNP as a sensory element provided us a broad spectrum of innovative approaches for the detection of metal ions, small molecules, proteins, nucleic acids, malignant cells, etc. in a rapid and efficient manner.37



Figure 1

Physical properties of AuNPs and schematic illustration of an AuNP-based detection system.



In this current review, we have highlighted the several synthetic routes and properties of AuNPs that make them excellent probes for different sensing strategies. Furthermore, we will discuss various sensing strategies and major advances in the last two decades of research utilizing AuNPs in the detection of variety of target analytes including metal ions, organic molecules, proteins, nucleic acids, and microorganisms.

/pdf/gold-nanoparticles-in-chemical-and-biological-sensing-5e2qojkdzn.pdf

Gold nanoparticles in chemical and biological sensing.

I read this book the same weekend that the Packers took on the Rams, and the experience of the latter event, obviously, colored my judgment. Although I abhor anything that smacks of being a handbook (like, \"How to Earn a Merit Badge in Neurosurgery\") because too many volumes in biomedical science already evince a boyscout-like approach, I must confess that parts of this volume are fast, scholarly, and significant, with certain reservations. I like parts of this well-illustrated book because Dr. Sj6strand, without so stating, develops certain subjects on technique in relation to the acquisition of judgment and sophistication. And this is important! So, given that the author (like all of us) is somewhat deficient in some areas, and biased in others, the book is still valuable if the uninitiated reader swallows it in a general fashion, realizing full well that what will be required from the reader is a modulation to fit his vision, propreception, adaptation and response, and the kind of problem he is undertaking. A major deficiency of this book is revealed by comparison of its use of physics and of chemistry to provide understanding and background for the application of high resolution electron microscopy to problems in biology. Since the volume is keyed to high resolution electron microscopy, which is a sophisticated form of structural analysis, but really morphology in a modern guise, the physical and mechanical background of The instrument and its ancillary tools are simply and well presented. The potential use of chemical or cytochemical information as it relates to biological fine structure , however, is quite deficient. I wonder when even sophisticated morphol-ogists will consider fixation a reaction and not a technique; only then will the fundamentals become self-evident and predictable and this sine qua flon will become less mystical. Staining reactions (the most inadequate chapter) ought to be something more than a technique to selectively enhance contrast of morphological elements; it ought to give the structural addresses of some of the chemical residents of cell components. Is it pertinent that auto-radiography gets singled out for more complete coverage than other significant aspects of cytochemistry by a high resolution microscopist, when it has a built-in minimal error of 1,000 A in standard practice? I don't mean to blind-side (in strict football terminology) Dr. Sj6strand's efforts for what is \"routinely used in our laboratory\"; what is done is usually well done. It's just that …

Methods in Enzymology.

基礎講座 電気泳動(Electrophoresis)

The use of microbial fuel cells to generate electrical current is increasingly being seen as a viable source of renewable energy production In this Progress article, Bruce Logan highlights recent advances in our understanding of the mechanisms used by exoelectrogenic bacteria to generate electrical current and the important factors to consider in microbial fuel cell design There has been an increase in recent years in the number of reports of microorganisms that can generate electrical current in microbial fuel cells Although many new strains have been identified, few strains individually produce power densities as high as strains from mixed communities Enriched anodic biofilms have generated power densities as high as 69 W per m2 (projected anode area), and therefore are approaching theoretical limits To understand bacterial versatility in mechanisms used for current generation, this Progress article explores the underlying reasons for exocellular electron transfer, including cellular respiration and possible cell–cell communication

Exoelectrogenic bacteria that power microbial fuel cells

One type of genuine fuel cell that does hold promise in the long-term is the biological fuel cell. Unlike conventional fuel cells, which employ hydrogen, ethanol and methanol as fuel, biological fuel cells use organic products produced by metabolic processes or use organic electron donors utilized in the growth processes as fuels for current generation. A distinctive feature of biological fuel cells is that the electrode reactions are controlled by biocatalysts, i.e. the biological redox-reactions are enzymatically driven, while in chemical fuel cells catalysts such as platinum determine the electrode kinetics. This article provides a brief introduction to biological fuel cells.along with their envisaged applications.

Biological fuel cells and their applications

Direct electron transfer with yeast cells and construction of a mediatorless microbial fuel cell.

Electrooxidation of alcohols and sugars catalysed on a nickel oxide modified glassy carbon electrode

Herein we report for the first time the fabrication of a rechargeable, benign, skin-worn Ag–Zn tattoo battery using unconventional materials, such as screen printed electrodes, temporary tattoo paper, alkaline gel electrolytes and a PDMS cover for sealing the battery. The tattoo battery can be easily worn by a person for powering wearable devices. Detailed characterization of a typical Ag–Zn tattoo cell reveals a capacity density in the range 1.3–2.1 mA h cm−2 and stability up to 13 cycles. The tattoo cell exhibits a stable open circuit voltage of 1.5 V over a 5 days period and endures repeated stretching and bending strain cycles with minimal decrement in its performance. The lateral arrangement of the negative and positive electrodes allows the integration of several cells into a battery in series or parallel combination for tuning the discharge capacity and voltage to the desired values. The practical nature of the tattoo battery was illustrated by applying it to a human subject's skin followed by lighting a red LED. The epidermal tattoo battery thus meets the demands of wearable power sources, including mechanical compliance and tunable discharge capacity, to power body-worn electronic devices.

http://smeng.ucsd.edu/wp-content/uploads/An-epidermal-alkaline-rechargeable-Ag-Zn-printable-tattoo-battery-for-wearable-electronics.pdf

An epidermal alkaline rechargeable Ag–Zn printable tattoo battery for wearable electronics

https://krc.cecri.res.in/ro_2012/2012-046.pdf

Sheela Berchmans

Papers

Biological fuel cells and their applications

Direct electron transfer with yeast cells and construction of a mediatorless microbial fuel cell.

Electrooxidation of alcohols and sugars catalysed on a nickel oxide modified glassy carbon electrode

An epidermal alkaline rechargeable Ag–Zn printable tattoo battery for wearable electronics

Determination of inorganic phosphate by electroanalytical methods: A review