Progress and challenges for biosensors using plant tissue materials

Biocatalytic sensors using plant tissue materials in conjunction with electrochemical elements offer an alternative to biosensors based on isolated enzymes. In favorable cases, such plant based sensors show attractive analytical properties in addition to low cost, simplicity of construction, and reduced co-factor requirements. A review of the current state of the art is provided along with some previously unpublished examples of new biosensors using plant tissue materials.     

Bioelectroanalysis of pharmaceutical compounds

Recent developments in the bioelectroanalysis of pharmaceutical compounds are reviewed, concentrating particularly on the development of electrode materials and measurement strategies and on their application. The advantages of electroanalytical techniques as alternatives to other analytical procedures such as rapid response, sensitivity and low detection limits are highlighted and illustrated. Particular emphasis is given to carbon-based materials for voltammetric electroanalysis; new potentiometric sensors and electrochemical biosensors are also reviewed.     

Molecular design of polymeric materials for biotechnology and medicine

This review describes new polymer materials for biomedical applications developed in the Polymers for Biology Laboratory of the Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences. These include composite rigid sorbents for biochromatography, polymer dispersions for immunoassay, polymer hydrogels for immobilization of enzymes and cells, and polymer ultra thin films as biomembrane models and materials for biosensors. Some general and specific properties of these new materials and models as well as examples of their applications are discussed.     

New redox mediator-modified polysulfone composite films for the development of dehydrogenase-based biosensors

This work presents polysulfone membranes as new materials for the development of compact dehydrogenase-based biosensors. Composite films were prepared by mixing polysulfone with graphite and were deposited on epoxy-graphite composite electrodes. Redox mediators were successfully immobilized in the composite film leading to highly reproducible biosensors, without leakage of the immobilized species. This results in a more reliable analytical system as, at the same time, problems of electrode fouling related to the detection of the coenzyme nicotinamide adenine dinucleotide (NADH) on which is based the amperometric detection of dehydrogenase-based biosensors are avoided. Scanning electron microscopy was used to study the morphological characteristics of the surface and the cross-section of the polysulfone-graphite composite films. Several procedures to immobilize enzymes in these membranes were demonstrated. Glutamate dehydrogenase (GlDH) was immobilized as an example of dehydrogenase enzyme, in this case for the development of an ammonium biosensor. High sensitivity, good selectivity, wide linear ranges and short response times were obtained for the optimized sensors and biosensors. Their good performance combined with the simplicity of the construction method, make the polysulfone-graphite composite films attractive matrices for the development of new enzyme-based biosensors, especially those based on dehydrogenase enzymes.     

Plant tissue-and photosynthesis-based biosensors

Biosensors are promising biotools, alternative or complementary to conventional analysis techniques, for fast, simple, cheap and reliable screening. This article reviews the biosensors that use plant components as biorecognition elements. In the first section, plant tissue-based biosensors are summarised and classified according to the enzyme used. Afterwards, photosynthesis-based biosensors, including the types of photosynthetic materials and immobilisation methods, are described.     

Nanoparticle-enzyme hybrid systems for nanobiotechnology

Biomolecule-nanoparticle (NP) [or quantum-dot (QD)] hybrid systems combine the recognition and biocatalytic properties of biomolecules with the unique electronic, optical, and catalytic features of NPs and yield composite materials with new functionalities. The biomolecule-NP hybrid systems allow the development of new biosensors, the synthesis of metallic nanowires, and the fabrication of nanostructured patterns of metallic or magnetic NPs on surfaces. These advances in nanobiotechnology are exemplified by the development of amperometric glucose sensors by the electrical contacting of redox enzymes by means of AuNPs, and the design of an optical glucose sensor by the biocatalytic growth of AuNPs. The biocatalytic growth of metallic NPs is used to fabricate Au and Ag nanowires on surfaces. The fluorescence properties of semiconductor QDs are used to develop competitive maltose biosensors and to probe the biocatalytic functions of proteases. Similarly, semiconductor NPs, associated with electrodes, are used to photoactivate bioelectrocatalytic cascades while generating photocurrents.     

Electrochemical biosensing based on universal affinity biocomposite platforms

Rigid conducting biocomposites are versatile and effective transducing materials for the construction of a wide range of amperometric biosensors such as immunosensors, genosensors and enzymosensors, particularly if the transducer is bulk-modified with universal affinity biomolecules. The strept(avidin)-graphite-epoxy biocomposite could be considered as an universal immobilization platform whereon biotinylated DNAs, oligonucleotides, enzymes or antibodies can be captured by means of the highly affinity (strept)avidin-biotin reaction. Universal affinity biocomposite-based biosensors offer many potential advantages compared to more traditional electrochemical biosensors commonly based on a biologically surface-modified transducer. The integration of many materials into one matrix is their main advantage. As biological bulk-modified materials, the conducting biocomposites act not only as transducers, but also as reservoir for the biomaterial. After its use, the electrode surface can be renewed by a simple polishing procedure, establishing a clear advantage of these approaches relative to classical biosensors and other common biological assays. Moreover, the same material is useful for the analysis of many molecules whose determinations are based on genetic, enzymatic or immunological reactions. The different strategies for electrochemical genosensing, immunosensing and enzymosensing, all of them being dependent on the presence of a redox enzyme marker for the generation of the electrochemical signal, based on this universal affinity biocomposite platform are all presented and discussed.     

Bio-smart hydrogels: co-joined molecular recognition and signal transduction in biosensor fabrication and drug delivery

Two classes of polymers that are currently receiving widespread attention in biosensor development are hydrogels and conducting electroactive polymers. The present study reports on the integration of these two materials to produce electroactive hydrogel composites that physically entrap enzymes within their matrices for biosensor construction and chemically stimulated controlled release. Enhanced biosensing capabilities of these membranes have been demonstrated in the fabrication of glucose, cholesterol and galactose amperometric biosensors. All biosensors displayed extended linear response ranges (10(-5)-10(-2) M), rapid response times (<60 s), retained storage stabilities of up to 1 year, and excellent screening of the physiological interferents ascorbic acid, uric acid, and acetaminophen. When the cross-linked hydrogel components of these composite membranes were prepared with the amine containing dimethylaminoethyl methacrylate monomer the result was polymeric devices that swelled in response to pH changes (neutral to acidic). Entrapment of glucose oxidase within these materials made them glucose-responsive through the formation of gluconic acid. When insulin was co-loaded with glucose oxidase into these "bio-smart" devices, there was a twofold increase in insulin release rate when the devices were immersed in glucose solutions. This demonstrates the potential of such systems to function as a chemically-synthesized artificial pancreas.     

Hybrid nanoparticles based on organized protein immobilization on fullerenes

Nanoscale carbon materials (i.e., fullerenes and nanotubes) are an attractive platform for applications in biotransformations and biosensors. The interesting properties displayed by nanoparticles demand new strategies for the manipulation of these materials on the nanoscale. Controlled modification of their surface with biomolecules is required to fully realize their potential in bionanotechnology. In this work, immobilization of a fullerene derivative with a mutant subtilisin is demonstrated, and the effect of the fullerene on the protein activity is determined. The fullerene-conjugated enzyme had improved catalytic properties in comparison to subtilisin immobilized on nonporous silica. Further, the pH profile of free and fullerene-conjugated subtilisin were almost identical.     

Making bio-sense of toxicity: new developments in whole-cell biosensors

Bacterial whole-cell biosensors are very useful for toxicity measurements of various samples. Semi-specific biosensors, containing fusions of stress-regulated promoters and reporter genes, have several advantages over the traditional, general biosensors that are based on constitutively expressed reporter genes. Furthermore, semi-specific biosensors are constantly being refined to lower their sensitivity and, in combination, are able to detect a wide range of toxic agents. However, the requirement for a positive response of these biosensors to toxicants can result in false-negative responses. The application of in situ inoculation and single-cell detection, combined with the introduction of new reporter genes and refined detection equipment, could lead to the extensive use of semi-specific, stress-responsive biosensors for toxicity estimations in the future.     

量子点对细菌的标记及抗菌作用

目的量子点是近年来发展起来的一种新型的荧光纳米材料,与传统的材料相比具有独特的性质,所以在生物传感器、实时追踪、多色标记及成像等方面有着广泛的应用。本文主要对量子点在细菌标记和抗菌等方面的应用进行了综述。     

Application of conducting polymers to biosensors

Recently, conducting polymers have attracted much interest in the development of biosensors. The electrically conducting polymers are known to possess numerous features, which allow them to act as excellent materials for immobilization of biomolecules and rapid electron transfer for the fabrication of efficient biosensors. In the present review an attempt has been made to describe the salient features of conducting polymers and their wide applications in health care, food industries, environmental monitoring etc.     

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.     

New trends in instrumental design for surface plasmon resonance-based biosensors

Surface plasmon resonance (SPR)-based biosensing is one of the most advanced label free, real time detection technologies. Numerous research groups with divergent scientific backgrounds have investigated the application of SPR biosensors and studied the fundamental aspects of surface plasmon polaritons that led to new, related instrumentation. As a result, this field continues to be at the forefront of evolving sensing technology. This review emphasizes the new developments in the field of SPR-related instrumentation including optical platforms, chips design, nanoscale approach and new materials. The current tendencies in SPR-based biosensing are identified and the future direction of SPR biosensor technology is broadly discussed.     

Ion sensitive field effect transducer-based biosensors

Ion-sensitive field effect transistors (ISFETs) have found growing interest in the rapidly developing field of biosensors. The principles, application and new developing techniques of ISFET-based biosensors are reviewed.     

The Use of Whole-Cell Biosensors to Detect and Quantify Compounds or Conditions Affecting Biological Systems

A new and promising technique in microbial ecology and environmental biology is the use of whole-cell bacterial biosensors. This minireview describes the use of such biosensors for detection and quantification of various compounds and other conditions affecting bacterial expression of different genes. Three types of biosensors (nonspecific, stress-induced, and specific biosensors) are described including their use in different environments. We present tables of published biosensors, including gene fusions, host organisms, and environments in which they are used. We here describe the use of different reporter genes in the construction of biosensors and discuss their use as tools for monitoring the bioavailability of pollutants and their potential use in studying microbial ecology in general.     

Prion-based nanomaterials and their emerging applications

ABSTRACT

Protein misfolding and aggregation into highly ordered fibrillar structures have been traditionally associated with pathological processes. Nevertheless, nature has taken advantage of the particular properties of amyloids for functional purposes, like in the protection of organisms against environmental changing conditions. Over the last decades, these fibrillar structures have inspired the design of new nanomaterials with intriguing applications in biomedicine and nanotechnology such as tissue engineering, drug delivery, adhesive materials, biodegradable nanocomposites, nanowires or biosensors. Prion and prion-like proteins, which are considered a subclass of amyloids, are becoming ideal candidates for the design of new and tunable nanomaterials. In this review, we discuss the particular properties of this kind of proteins, and the current advances on the design of new materials based on prion sequences.     

The Sonogel-Carbon materials as basis for development of enzyme biosensors for phenols and polyphenols monitoring: a detailed comparative study of three immobilization matrixes

Three amperometric biosensors based on immobilization of tyrosinase on a new Sonogel-Carbon electrode for detection of phenols and polyphenols are described. The electrode was prepared using high energy ultrasounds (HEU) directly applied to the precursors. The first biosensor was obtained by simple adsorption of the enzyme on the Sonogel-Carbon electrode. The second and the third ones, presenting sandwich configurations, were initially prepared by adsorption of the enzyme and then modification by mean of polymeric membrane such as polyethylene glycol for the second one, and the ion-exchanger Nafion in the case of the third biosensor. The optimal enzyme loading and polymer concentration, in the second layer, were found to be 285 U and 0.5%, respectively. All biosensors showed optimal activity at the following conditions: pH 7, -200 mV, and 0.02 mol l(-1) phosphate buffer. The response of the biosensors toward five simple phenols derivatives and two polyphenols were investigated. It was found that the three developed tyrosinase Sonogel-Carbon based biosensors are in satisfactory competitiveness for phenolic compounds determination with other tyrosinase based biosensors reported in the literature. The detection limit, sensitivity, and the apparent Michaelis-Menten constant K(m)(app) for the Nafion modified biosensor were, respectively, 0.064, 0.096, and 0.03 micromol, 82.5, 63.4, and 194 nA micromol(-1)l(-1), and 67.1, 54.6, and 12.1 micromol l(-1) for catechol, phenol, and 4-chloro-3-methylphenol. Hill coefficient values (around 1 for all cases), demonstrated that the immobilization method does not affect the nature of the enzyme and confirms the biocompatibility of the Sonogel-Carbon with the bioprobe. An exploratory application to real samples such as beers, river waters and tannery wastewaters showed the ability of the developed Nafion/tyrosinase/Sonogel-Carbon biosensor to retain its stable and reproducible response.     

Immobilization of enzymes into nanocavities for the improvement of biosensor stability

Nanoporous materials with different pore sizes are evaluated as immobilization and stabilization matrices of proteins for the development of highly stable biosensors. It has been proven experimentally that confinement of proteins in cages with a diameter that is 2-6 times larger than their size increases considerably the stability of the biomolecules, as has been shown earlier by theoretical calculations. Porous silica beads with pore sizes of 10nm were utilized for the immobilization of the enzymes HRP and GOx with diameters in the order of 5 and 7 nm, respectively. The sensitivity of the corresponding biosensor systems was monitored for 70 h under continuous operation conditions (+600 mV) and it was found that the stabilization factor of GOx is 1.7 times higher compared to HRP. Also the stabilization efficiency of enzymes against leaching and inactivation in porous polymer beads with pore diameters of 10 and 30 nm was examined. The leaching rate of the enzyme AChE from the 30 nm polymer beads was found to be 1.1 times higher than that from the 10nm beads. At the same time the remaining activity of GOx biosensors after 5 days of continuous operation conditions (+600 mV) was found to be 2.1 times higher when the enzyme had been immobilized in the 10nm beads compared to the 30 nm beads. It is thus evident that the matching between the pore size of nanoporous materials and the molecular size of enzymes is essential for the development of biosensors with extended shelf and operational lifetimes.     

生物芯片、生物传感器和生物信息学

近年来,在生物技术和医学研究领域涌现出了许多新技术平台,其中就包括生物芯片技术和生物传感器技术。生物芯片和生物传感器的构建都必须以生物信息学为基础,而两种技术平台应用所得出的数据和结果又反过来大大丰富和充实了生物信息学本身。本分析概述了生物芯片和生物传感器两种技术平台以及生物信息学,对三之间的相互关系进行了讨论。