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

Department of Materials Science, University of Patras, 26504 Rio Patras, Greece, Theoretical and Physical Chemistry Institute, National Hellenic Research Foundation, 48 Vass. Constantinou Avenue, 116 35 Athens, Greece, Institut de Biologie Moleculaire et Cellulaire, UPR9021 CNRS, Immunologie et Chimie Therapeutiques, 67084 Strasbourg, France, and Dipartimento di Scienze Farmaceutiche, Universita di Trieste, Piazzale Europa 1, 34127 Trieste, Italy

Chemistry of Carbon Nanotubes

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.

Polydopamine and Its Derivative Materials: Synthesis and Promising Applications in Energy, Environmental, and Biomedical Fields

Phenolics are broadly distributed in the plant kingdom and are the most abundant secondary metabolites of plants. Plant polyphenols have drawn increasing attention due to their potent antioxidant properties and their marked effects in the prevention of various oxidative stress associated diseases such as cancer. In the last few years, the identification and development of phenolic compounds or extracts from different plants has become a major area of health- and medical-related research. This review provides an updated and comprehensive overview on phenolic extraction, purification, analysis and quantification as well as their antioxidant properties. Furthermore, the anticancer effects of phenolics in-vitro and in-vivo animal models are viewed, including recent human intervention studies. Finally, possible mechanisms of action involving antioxidant and pro-oxidant activity as well as interference with cellular functions are discussed.

/pdf/plant-phenolics-extraction-analysis-and-their-antioxidant-2ee2ft7zgl.pdf

Plant phenolics: extraction, analysis and their antioxidant and anticancer properties.

A sensitive amperometric bromate sensor based on multi-walled carbon nanotubes/phosphomolybdic acid composite film

Determination of microorganisms with a quartz crystal microbalance sensor

Stereoselective histidine sensor based on molecularly imprinted sol-gel films

Electrochemical quartz crystal impedance study on the overoxidation of polypyrrole–carbon nanotubes composite film for amperometric detection of dopamine

Acquiring multilayer information on diverse biomarkers with different spatial distributions at the cellular level is crucial for monitoring the progression of cancers. Herein, a dual-signal-tagged chimeric DNA-functionalized titanium carbide MXenes nanoprobe (dcDNA-Ti3C2) that responds to biomarkers with different cellular locations from plasma membrane to cytoplasm was designed toward this end. In the presence of cancer biomarkers, including transmembrane glycoprotein mucin 1 (MUC1) and cytoplasmic microRNA-21 (miR-21), the recognition between MUC1 and its aptamer in the dcDNA-Ti3C2 probe induces the separation of TAMRA-MUC1 aptamer from Ti3C2 MXenes, thereby resulting in an increase in red fluorescence; and the hybridization of miR-21 with the hairpin probe triggers the increase of green fluorescence. As a result, dual analysis of MUC1 and miR-21 at low-nanomolar concentrations in vitro, as well as in situ simultaneous imaging of the biomarkers within MCF-7 breast cancer cells, was achieved. The feasibility of the nanoprobe was further demonstrated by monitoring the expression changes of both the biomarkers in cancer cells under different inhibitor combinations. Therefore, this strategy allows us to acquire the expression levels and spatial distributions of different biomarkers in living cells, providing a helpful tool for reliable diagnosis of cancers and basic understanding their progression.

Shouzhuo Yao

Papers

A sensitive amperometric bromate sensor based on multi-walled carbon nanotubes/phosphomolybdic acid composite film

Determination of microorganisms with a quartz crystal microbalance sensor

Stereoselective histidine sensor based on molecularly imprinted sol-gel films

Electrochemical quartz crystal impedance study on the overoxidation of polypyrrole–carbon nanotubes composite film for amperometric detection of dopamine

Chimeric DNA-Functionalized Titanium Carbide MXenes for Simultaneous Mapping of Dual Cancer Biomarkers in Living Cells.