Nanomaterial-based electrochemical biosensors for medical applications

With recent advances in nanotechnology, great progress has been made in biosensors based on nanomaterials, but there are still numerous challenges to overcome. We describe nanomaterial-based biosensors for researchers new to the field, paying particular attention to metal nanoparticles and carbon nanotube (CNT)-based label-free approaches. Label-free monitoring of biorecognition events provides a promising platform, which is simple, cost-effective, and requires no external modification to biomolecules. Using examples from recent reports, we illustrate the diversity of biological recognition events and the range of experimental techniques employed for metal-nanoparticle-based and label-free characterization.     

Principles and applications of electrochemical and optical biosensors

The principles of biocatalytic and bioaffinity biosensors are reviewed with emphasis on electron transfer-type enzyme sensors, optical enzyme sensors and optical immunosensors for homogeneous immunoassay. An enzyme sensor for ethanol was fabricated by electrochemical polymerization of pyrrole onto the surface of platinized platinum-adsorbed alcohol dehydrogenase—NAD—Meldola Blue. Ethanol was determined amperometrically by measuring the oxidative current through polypyrrole. An optical enzyme sensor is exemplified by an acethylcholine sensor based on an optical pH fibre sensor using a thin polyaniline film. The optical immunosensor for homogeneous immunoassay consists of an optical fibre, the end of the which is coated with an optically transparent platinum electrode. With using luminol as a label, highly sensitive homogeneous immunoassay is carried out by measuring the electrochemical luminescence of the label.     

Recent advances on the development of graphene-based field-effect transistors,electrochemical biosensors and electrochemiluminescence biosensors

Graphene, a honeycomb lattice of carbon material with single-atom-layer structure, demonstrates extraordinary mechanical, thermal, chemical and electronic properties. Thus, it has sparked tremendous interests in various fields, such as energy storage and conversion devices, field-effect transistors (FET), chemical sensors and biosensors. In this review, we will first focus on the synthesis method of graphene and the fabrication strategy of graphene-based materials. Subsequently, the construction of graphene-based biosensors are introduced, in which three kinds of biosensors are discussed in details, including the FET, electrochemical biosensors and electrochemiluminescence (ECL) biosensors. The performances of the state-of-the-art biosensors on the detection of biomolecules are also displayed. Finally, we also highlight some critical challenges remain to be solved and the development in this field for further research.     

Silica-based electrochemical sensors and biosensors: Recent trends

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Recent developments in potentiometric biosensors for biomedical analysis

A large variety of potentiometric biosensors is developed using biocatalytic and bioaffinity-based biosensing schemes. However, only few of them could be applied for the biomedical analysis. The most promising are those for the detection of main products of protein metabolism, namely urea and creatinine. A novel group of potentiometric biosensors is constituted by bioaffinity-based devices that could be used for immunoassays or genoanalysis. This paper reviews the recent trends in these fields as well as discusses advantages, limitations and pitfalls of the developed biosensors. Some potentiometric biosensors useful for real biomedical analysis are reported in detail.     

Recent developments in electrochemical water oxidation

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Disposable electrochemical biosensors.

The market for decentralized clinical testing is undergoing expansion. Electrochemical biosensors represent one approach to the different demands of this market. A range of sensing systems are described which use electrochemical techniques for the measurement of various analytes and which have been demonstrated to be applicable to the manufacturing methods required for single-use disposable tests.     

电化学生物传感器测定甲胎蛋白的研究进展

人体血清中甲胎蛋白(AFP)含量已作为肝癌检测的重要指标,快速而准确地检测血清中的AFP含量对肝癌的早期诊断和预后都有极为重要的作用。传统的酶联免疫法存在分析时间长、前处理繁琐等不利因素。利用免疫技术与电化学检测技术结合起来的电化学免疫传感器,由于具有操作简单、灵敏度高、特异性强及成本低等特点,而得到广泛关注。本文将根据所采用的不同检测方式及修饰材料等方面对近年来电化学免疫传感器检测AFP的研究与应用进行评述,并对其发展趋势进行了展望。     

Recent developments in electrochemical detection of cadmium

Heavy metal cadmium (Cd) poses extreme toxicity to the environmental and human health, thus its detection provides a great challenge in the environmental and analytical science, yet the solution is needed urgently owing to the adverse effects. During the past years, the electrochemical techniques have received considerable attentions for Cd²⁺ determination due to their unique advantages. In this review, a common introduction was provided firstly and followed by the detection principles. Then, a fully comprehensive elucidation of the recent developments in electrochemical detection of Cd²⁺ was presented. Finally, the critical challenge and perspectives of Cd²⁺ detection were outlined.     

Recent developments of derivative spectrophotometry and their analytical applications.

Articles about the development of derivative spectrophotometric methods and analytical applications of derivative spectrophotometry (DS) published in the last nine years (since 1994) are reviewed.     

Carbon nanostructured materials for applications in nano-medicine, cultural heritage, and electrochemical biosensors

This review covers applications of pristine and functionalized single-wall carbon nanotubes (SWCNTs) in nano-medicine, cultural heritage, and biosensors. The physicochemical properties of these engineered nanoparticles are similar to those of ultrafine components of airborne pollution (UF) and might have similar adverse effects. UF may impair cardiovascular autonomic control (inducing a high-risk condition for adverse cardiovascular effects), cause mammalian embryo toxicity, and increase geno-cytotoxic risk. SWCNTs coated with a biopolymer, for example polyethylenimine (PEI), become extremely biocompatible, hence are useful for in-vivo and in-vitro drug delivery and gene transfection. It is also possible to successfully immobilize a human enteric virus on PEI/SWCNT composites, suggesting application as a carrier in non-permissive media. The effectiveness of carbon nanostructured materials in the cleaning, restoration, and consolidation of deteriorated historical surfaces has been widely shown by the use of carbon nanomicelles to remove black dendritic crust from stone surfaces. The nanomicelles, here, have the twofold role of delivery and controlled release of the cleaning agents. The high biocompatibility of functionalized SWCNTs with enzymes and proteins is a fundamental feature used in the assembly of electrochemical biosensors. In particular, a third-generation protoporphyrin IX-based biosensor has been assembled for amperometric detection of nitrite, an environmental pollutant involved in the biodeterioration and black encrustation of historical surfaces.     

Propofol-imprinted membranes with potential applications in biosensors

Herein we describe a new thin film imprinted polymer for propofol (active ingredient of a commonly used general intravenous anaesthetic) developed on a membrane support. Propofol binds to this polymer in 2 min and can be removed and tested in 1 min, giving a total assay time of 3 min. The non-specific binding to the polymer is below the detection limit (0.1 μg/ml) and the response rate is below the rate of metabolism of the anaesthetic. Tests performed with this polymer against propofol-spiked blood samples showed good linearity and specificity at clinically relevant concentrations of 1-10 μg/ml and the working range for the system is 0.1-50 μg/ml. The polymer is easily regenerated and can be re-used for subsequent testing (in blood up to 5000 cycles). These results suggest suitability for use in an on-line propofol detection system.     

Recent developments and applications of grazing incidence scattering

A review of recent developments and applications of grazing incidence scattering is presented. In particular, high energy X-rays now make possible the investigation of buried, solid–liquid and liquid–liquid interfaces with high spatial resolution and possibly time resolution. Elemental sensitivity can be provided by resonant reflectivity and fluorescence based techniques using hard and soft X-rays. The use of partial coherence at third generation synchrotron sources enables one to go beyond the statistical properties of interfacial systems and to investigate their dynamics.     

Polymer light-emitting electrochemical cells: Recent developments to stabilize the p-i-n junction and explore novel device applications

Polymer light-emitting electrochemical cells (PLECs) employ a thin layer of a luminescent conjugated polymer admixed with an ionic source and an ionic conductor for the in-situ formation of p-i-n junction and subsequent efficient injections of both electrons and holes.The junction formation enables the use of air-stable conductors as the cathode and a relatively thick emissive polymer layer that is more compatible with low-cost solution-based processes.This paper overviews the operation mechanism of the PLECs,the properties and drawbacks of the devices.The employment of crosslinkable ionic conductors to stabilize the p-i-n junction is reviewed.The resulting static junction electroluminesces light at high brightness,high efficiency,and prolonged lifetime.Silver paste and carbon nanotubes can be used as the cathode,thus,PLECs were fabricated by lamination.Using single wall carbon nanotubes coated elastic substrate as both anode and cathode,the PLECs can be made highly stretchable.     

Recent developments and applications of NSE in soft matter

Neutron Spin Echo is probably the youngest spectroscopic method in neutron scattering. After a brief introduction I will try to give a short account of recent progress on the instrumentation. Through some recent examples I will illustrate that NSE is a powerful tool in colloid science applied to both “old” and recent problems. With new instrumentation we will be able to tackle new problems and one of those areas in which there has been recently exciting progress is the field of surface science.     

Birch还原及其在合成中应用进展

Birch还原是联接芳香族和脂肪族化合物的桥梁,它使许多芳香族衍生物成为合成脂肪族化合物,尤其六元脂环天然产物的起始原料,因此Birch还原是有机合成中很有用的方法。本文主要以几种最普通芳香族化合物用于脂肪族天然产物的合成例子,讨论Birch还原的合成潜力及其还原产物的合成应用,介绍了Birch还原在合成应用中的最新进展。     

Recent developments on chiral ionic liquids: design, synthesis, and applications

The recent progress in chiral ionic liquids with respect to their syntheses and applications in enantioselective reactions and chiral recognition is described. In addition to the conventional chiral ionic liquids derived from chiral natural products, a library of novel chiral spiro compounds, including spiro bis(pyridinium) and spiro bis(imidazolium) salt, is also described.     

Recent developments of temperature-responsive polymers for ophthalmic applications

Blindness is one of the most feared disabilities. From cataracts and glaucoma to age-related macular degeneration and retinal vascular diseases, ocular diseases have adverse impacts on patients and pose a huge burden to the healthcare system. The World Health Organization estimates that out of 2.2 billion people with visual impairment, almost half of the cases can be prevented or has yet to be addressed. This presents an urgent clinical and societal need to be met. Temperature-sensitive hydrogels are one of the most biocompatible materials, which can be applied into the eye. By exploiting physiological temperature as a stimulus for in situ gel formation, control of the mechanical properties, rate of drug release, and biomechanical interactions can be tuned. They are very versatile and have immense potential in ocular applications by acting as vitreous substitutes in retinal surgery or topical eye drops and lenses for ocular discomfort and inflammation. In this article, we provide a review of the recent developments in temperature-responsive polymers in ophthalmic therapy in the past 5 years including retinal detachment, retinal vascular diseases, dry eyes, cataracts, age-related macular degeneration, and glaucoma.