FET-based nanobiosensors for the detection of smell and taste

Various nanobiosensors composed of biomaterials and nanomaterials have been developed, due to their demonstrated advantage of showing high performance. Among various biomaterials for biological recognition elements of the nanobiosensor, sensory receptors, such as olfactory and taste receptors, are promising biomaterials for developing nanobiosensors, because of their high selectivity to target molecules. Field-effect transistors(FET) with nanomaterials such as carbon nanotube(CNT), graphene, and conducting polymer nanotube(CPNT), can be combined with the biomaterials to enhance the sensitivity of nanobiosensors.Recently, many efforts have been made to develop nanobiosensors using biomaterials, such as olfactory receptors and taste receptors for detecting various smells and tastes. This review focuses on the biomaterials and nanomaterials used in nanobiosensor systems and studies of various types of nanobiosensor platforms that utilize olfactory receptors and taste receptors which could be applied to a wide range of industrial fields, including the food and beverage industry, environmental monitoring, the biomedical field, and anti-terrorism.     

荧光纳米生物传感器研究进展

荧光纳米生物传感器检测物质具有灵敏度高、响应迅速、抗干扰性强、无需参比电极等特点而被广泛地运用于生物传感技术领域。本文综述了荧光纳米生物传感器种类和特点,介绍了国内外近期在荧光纳米生物传感器及在生物检测方面的一些研究成果及进展,并作了分析比较。着重讨论了纳米粒子荧光生物传感器和光纤纳米荧光生物传感器的特性及其在生物分析中的应用。     

Sustainable approaches towards green synthesis of TiO2 nanomaterials and their applications in photocatalysis-mediated sensing to monitor environmental pollution

Nanomaterials are gaining enormous interests due to their novel applications that have been explored nearly in every field of our contemporary society. In this scenario, preparations of nanomaterials following green routes have attracted widespread attention in terms of sustainable, reliable, and environmentally friendly practices to produce diverse nanostructures. In this review, we summarize the fundamental processes and mechanisms of green synthesis approaches of TiO₂ nanoparticles (NPs). We explore the role of plants and microbes as natural bioresources to prepare TiO₂ NPs. Particularly, focus has been made to explore the potential of TiO₂-based nanomaterials to design a variety of sensing platforms by exploiting the photocatalysis efficiency under the influence of a light source. These types of sensing are of massive importance for monitoring environmental pollution and therefore for inventing advanced strategies to remediate hazardous pollutants and offer a clean environment.     

The development of optical nanosensors for biological measurements

This article discusses and documents the basic concepts of, and developments in, the field of optical nanosensors and nanobiosensors. It describes the progression of this field of research from its birth up to the present, with emphasis on the techniques of sensor construction and their application to biological systems. After a brief overview of the techniques for fabricating nanometer-sized optical fibers, we describe the various types of transducer and bioreceptor molecule presently used for nanosensor and nanobiosensor fabrication.     

Emerging neuroskeletal signalling pathways: a review

Recent work has demonstrated that neurotransmitters, signalling molecules primarily associated with the nervous system, can have profound effects on the skeleton. Bone cells express a broad range of neurotransmitter receptors and transporters, and respond to receptor activation by initiating diverse intracellular signalling pathways, which modulate cellular function. Evidence of neuronal innervation in skeletal tissues, neurotransmitter release directly from bone cells and functional effects of pharmacological manipulation support the existence of a complex and functionally significant neurotransmitter-mediated signalling network in bone. This review aims to concisely summarise our current understanding of how neurotransmitters affect the skeletal system, focusing on their origin, cellular targets and functional effects in bone.     

Nanotechnology and biosensors

Nanotechnology is playing an increasingly important role in the development of biosensors. The sensitivity and performance of biosensors is being improved by using nanomaterials for their construction. The use of these nanomaterials has allowed the introduction of many new signal transduction technologies in biosensors. Because of their submicron dimensions, nanosensors, nanoprobes and other nanosystems have allowed simple and rapid analyses in vivo. Portable instruments capable of analyzing multiple components are becoming available. This work reviews the status of the various nanostructure-based biosensors. Use of the self-assembly techniques and nano-electromechanical systems (NEMS) in biosensors is discussed.     

Conducting polymer nanowires-based label-free biosensors

Label-free sensing technologies have recently attracted a great deal of interest for sensitive, rapid and facile analysis for applications in health care, environmental monitoring, food safety and homeland security. One-dimensional (1-D) nanostructures such as nanowires, configured as field-effect transistors (FETs)/chemiresistors that change conductance upon binding of charged macromolecules to receptors linked to the device surfaces are extremely attractive for label-free biosensors. Herein, we review recent advances in label-free biosensors based on conducting polymer nanowires based FET/chemiresistor. Specifically, we address the fabrication, functionalization, assembly/alignment and sensing applications of FET/chemiresistor based on these nanomaterials. The advantages and disadvantages of various fabrication, functionalization, and assembling procedures of these nanosensors are reviewed and discussed.     

Neurotransmitter transporters in schistosomes: Structure,function and prospects for drug discovery

Neurotransmitter transporters (NTTs) play a fundamental role in the control of neurotransmitter signaling and homeostasis. Sodium symporters of the plasma membrane mediate the cellular uptake of neurotransmitter from the synaptic cleft, whereas proton-driven vesicular transporters sequester the neurotransmitter into synaptic vesicles for subsequent release. Together these transporters control how much transmitter is released and how long it remains in the synaptic cleft, thereby regulating the intensity and duration of signaling. NTTs have been the subject of much research in mammals and there is growing interest in their activities among invertebrates as well. In this review we will focus our attention on NTTs of the parasitic flatworm Schistosoma mansoni. Bloodflukes of the genus Schistosoma are the causative agents of human schistosomiasis, a devastating disease that afflicts over 200 million people worldwide. Schistosomes have a well-developed nervous system and a rich diversity of neurotransmitters, including many of the small-molecule (“classical”) neurotransmitters that normally employ NTTs in their mechanism of signaling. Recent advances in schistosome genomics have unveiled numerous NTTs in this parasite, some of which have now been cloned and characterized in vitro. Moreover new genetic and pharmacological evidence suggests that NTTs are required for proper control of neuromuscular signaling and movement of the worm. Among these carriers are proteins that have been successfully targeted for drug discovery in other organisms, in particular sodium symporters for biogenic amine neurotransmitters such as serotonin and dopamine. Our goal in this chapter is to review the current status of research on schistosome NTTs, with emphasis on biogenic amine sodium symporters, and to evaluate their potential for anti-schistosomal drug targeting. Through this discussion we hope to draw attention to this important superfamily of parasite proteins and to identify new directions for future research.     

Surface plasmon resonance based biosensor technique: A review

Optical Surface plasmon resonance (SPR) biosensors represent the most advanced and developed optical label‐free biosensor technology. Optical SPR biosensors are a powerful detection and analysis tool that has vast applications in environmental protection, biotechnology, medical diagnostics, drug screening, food safety and security. This article reviews the recent development of SPR biosensor techniques, including bulk SPR and localized SPR (LSPR) biosensors, for detecting interactions between an analyte of interest in solution and a biomolecular recognition. The concepts of bulk and localized SPs and the working principles of both sensing techniques are introduced. Major sensing advances on biorecognition elements, measurement formats, and sensing platforms are presented. Finally, the discussions on both biosensor techniques as well as comparison of both SPR sensing techniques are made. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Neurotransmitters are regulators for the migration of tumor cells and leukocytes

Neurotransmitters are signal substances that have traditionally been regarded as mere mediators of signal states between cells in the nervous system. Whereas the mechanisms of this "classic" neurotransmitter regulation are well understood, only recently has new evidence come to light elucidating the modulatory role of neurotransmitters in immune function, and in the regulation of migration of leukocytes and tumor cells. The migration of leukocytes is, among other things, of primary importance for an anti-tumor immune response, whereas the migration of tumor cells is a prerequisite for invasion and the development of metastases. We here clarify and consolidate the latest tumor biological findings on the role of these neurotransmitters, which bind to serpentine receptors, and which are involved in leukocyte migration, tumor growth, invasion and metastasis. This review thus accentuates the complex, interactive involvement of neurotransmitters in the regulation of migration of both leukocytes and tumor cells.     

A review of LC–MS techniques and high-throughput approaches used to investigate drug metabolism by cytochrome P450s

One of the major challenges facing the pharmaceutical industry today is finding new ways to increase productivity, decrease costs whilst still ultimately developing new therapies that enhance human health. To help address these challenges the utilisation of analytical technologies and high-throughput automated platforms has been employed; in order to perform more experiments in a shorter time frame with increased data quality. One of the main in vitro techniques to assess new chemical entities in a discovery setting has been the use of recombinant liver enzymes, microsomes and hepatocytes. These techniques can help predict in vivo metabolism, clearance and potential drug–drug interactions of these new compounds by cytochrome P450s (the major drug metabolising enzymes). This in vitro methodology has been totally transformed in recent times by the use of automated liquid handling and HPLC tandem mass spectrometry detection techniques (LC–MS/MS). This review aims looking at recent advances in the methodology used to investigate drug metabolism by cytochrome P450s; including an up to date summary of high-throughput platforms including the use of automation and LC–MS/MS to facilitate greater throughput, chromatographic resolution and data quality.     

Advanced models of human skeletal muscle differentiation,development and disease: Three-dimensional cultures,organoids and beyond

Advanced in vitro models of human skeletal muscle tissue are increasingly needed to model complex developmental dynamics and disease mechanisms not recapitulated in animal models or in conventional monolayer cell cultures. There has been impressive progress towards creating such models by using tissue engineering approaches to recapitulate a range of physical and biochemical components of native human skeletal muscle tissue. In this review, we discuss recent studies focussed on developing complex in vitro models of human skeletal muscle beyond monolayer cell cultures, involving skeletal myogenic differentiation from human primary myoblasts or pluripotent stem cells, often in the presence of structural scaffolding support. We conclude with our outlook on the future of advanced skeletal muscle three-dimensional cultures (e.g. organoids and biofabrication) to produce physiologically and clinically relevant platforms for disease modelling and therapy development in musculoskeletal and neuromuscular disorders.     

Neurotransmitters as early signals for central nervous system development

During brain ontogenesis, the temporal and spatial generation of the different types of neuronal and glial cells from precursors occurs as a sequence of successive progenitor stages whose proliferation, survival and cell-fate choice are controlled by environmental and cellular regulatory molecules. Neurotransmitters belong to the chemical microenvironment of neural cells, even at the earliest stages of brain development. It is now established that specific neurotransmitter receptors are present on progenitor cells of the developing central nervous system and could play, during neural development, a role that has remained unsuspected until recently. The present review focuses on the occurrence of neurotransmitters and their corresponding ligand-gated ion channel receptors in immature cells, including neural stem cells of specific embryonic and neonatal brain regions. We summarize in vitro and in vivo data arguing that neurotransmitters could regulate morphogenetic events such as proliferation, growth, migration, differentiation and survival of neural precursor cells. The understanding of neurotransmitter function during early neural maturation could lead to the development of pharmacological tools aimed at improving adult brain repair strategies.     

基于上转换纳米材料的免疫检测技术应用

免疫分析法具有简便、快速、准确等特点，广泛应用于医学、食品、环境等领域检测，将免疫分析方法与纳米材料相结合可以提高免疫分析的性能。与传统纳米材料相比，上转换纳米颗粒（upconversion nanoparticles，UCNPs）具有光稳定性好、发光寿命长和狭窄及可调整的发射带等优秀的光学性质，与免疫分析相结合可显著降低背景噪声，提高分析灵敏度。本文简要介绍了UCNPs的发光机制，对UCNPs的合成和表面修饰方法进行了总结，并详细论述荧光共振能量转移、内滤效应、磁分离技术、上转化连接免疫吸附技术和上转换免疫层析技术五种基于UCNPs的免疫检测技术，最后对该技术所面临的挑战和前景进行总结和展望，以期为UCNPs免疫检测技术的发展提供理论指导。     

Separation methods used in the determination of choline and acetylcholine

Cholinergic neurotransmission has been the subject of intensive investigations in recent years due to increasing recognition of the importance of its roles in physiology, pathology and pharmacology. The fact that the disposition of a neurotransmitter may reflect its functional status has made the measurement of acetylcholine and/or its precursors and metabolites in biological fluids an integral part of cholinergic research. With evolving complexity in experimental approaches and designs, and correspondingly increasing demand on sensitivity, specificity and accuracy matching advancements in sophistication in analytical methods have been made. The present review attempts to survey the array of analytical techniques that have been adopted for the measurement of acetylcholine or its main precursor/metabolite choline ranging from simple bioassays, radioenzymatic assays, gas chromatography (GC) with flame ionization detection, GC with mass spectrometry (GC–MS) detection, high-performance liquid chromatography (HPLC) with electrochemical detection (ED), HPLC with MS (HPLC–MS) to the sophisticated combination of micro-immobilized enzymatic reactor, microbore HPLC and modified electrode technology for the detection of ultra-low levels with particular emphasis on the state of the art techniques.     

Nanomaterials‐based biosensors for detection of microorganisms and microbial toxins

Detection of microorganisms and microbial toxins is important for health and safety. Due to their unique physical and chemical properties, nanomaterials have been extensively used to develop biosensors for rapid detection of microorganisms with microbial cells and toxins as target analytes. In this paper, the design principles of nanomaterials‐based biosensors for four selected analyte categories (bacteria cells, toxins, mycotoxins, and protozoa cells), closely associated with the target analytes' properties is reviewed. Five signal transducing methods that are less equipment intensive (colorimetric, fluorimetric, surface enhanced Raman scattering, electrochemical, and magnetic relaxometry methods) is described and compared for their sensory performance (in term oflimit of detection, dynamic range, and response time) for all analyte categories. In the end, the suitability of these five sensing principles for on‐site or field applications is discussed. With a comprehensive coverage of nanomaterials, design principles, sensing principles, and assessment on the sensory performance and suitability for on‐site application, this review offers valuable insight and perspective for designing suitable nanomaterials‐based microorganism biosensors for a given application.     

Importance of being Nernst: Synaptic activity and functional relevance in stem cell-derived neurons

Functional synaptogenesis and network emergence are signature endpoints of neurogenesis. These behaviors provide higher-order confirmation that biochemical and cellular processes necessary for neurotransmitter release, post-synaptic detection and network propagation of neuronal activity have been properly expressed and coordinated among cells. The development of synaptic neurotransmission can therefore be considered a defining property of neurons. Although dissociated primary neuron cultures readily form functioning synapses and network behaviors in vitro, continuously cultured neurogenic cell lines have historically failed to meet these criteria. Therefore, in vitro-derived neuron models that develop synaptic transmission are critically needed for a wide array of studies, including molecular neuroscience, developmental neurogenesis, disease research and neurotoxicology. Over the last decade, neurons derived from various stem cell lines have shown varying ability to develop into functionally mature neurons. In this review, we will discuss the neurogenic potential of various stem cells populations, addressing strengths and weaknesses of each, with particular attention to the emergence of functional behaviors. We will propose methods to functionally characterize new stem cell-derived neuron (SCN) platforms to improve their reliability as physiological relevant models. Finally, we will review how synaptically active SCNs can be applied to accelerate research in a variety of areas. Ultimately, emphasizing the critical importance of synaptic activity and network responses as a marker of neuronal maturation is anticipated to result in in vitro findings that better translate to efficacious clinical treatments.     

Neurotransmitter release: the dark side of the vacuolar-H+ATPase

Vacuolar-H⁺ATPase (V-ATPase) is a complex enzyme with numerous subunits organized in two domains. The membrane domain V0 contains a proteolipid hexameric ring that translocates protons when ATP is hydrolysed by the catalytic cytoplasmic sector (V1). In nerve terminals, V-ATPase generates an electrochemical proton gradient that is acid and positive inside synaptic vesicles. It is used by specific neurotransmitter-proton antiporters to accumulate neurotransmitters inside their storage organelles. During synaptic activity, neurotransmitters are released from synaptic vesicles docked at specialized portions of the presynaptic plasma membrane, the active zones. A fusion pore opens that allows the neurotransmitter to be released from the synaptic vesicle lumen into the synaptic cleft. We briefly review experimental data suggesting that the membrane domain of V-ATPase could be such a fusion pore.We also discuss the functional implications for quantal neurotransmitter release of the sequential use of the same V-ATPase membrane domain in two different events, neurotransmitter accumulation in synaptic vesicles first, and then release from these organelles during synaptic activity.     

Biochips and other microtechnologies for physiomics

This paper presents a review of microtechnologies relevant to applications in cellular physiology, including biochips, electrochemical sensors and optrodic sensing techniques. Microelectrodes have been the main tools for measuring cellular electrophysiology, oxygen, nitric oxide, neurotransmitters, pH and various ions. Optical fiber sensing methods, such as indicator-based optrodes, with fluorescence lifetime measurement, are now emerging as viable alternatives to electroanalytical chemistry. These new optrode techniques are possible because of recent advances in the optoelectronics industry and are comparably easier to miniaturize, have faster response times, do not consume the analyte and have lower operational costs. This review serves as a summary and predicts future trends for both electrochemical and optical luminescence lifetime sensing as components in lab-on-a-chip devices for physiological sensing.