|
| ||
|
|
||
Biosensor Applications (biosensor + application)
Selected AbstractsThe Family of GFP-Like Proteins: Structure, Function, Photophysics and Biosensor Applications.PHOTOCHEMISTRY & PHOTOBIOLOGY, Issue 2 2006Introduction, Perspective ABSTRACT In this issue, we offer a symposium-in-print that is focused on several new advancements in fundamental research related to the family of GFP (green fluorescent protein)-like proteins. A few applied aspects are also included to illustrate the impact this amazing set of colored proteins has made on our understanding of cell biology at the molecular level. The six articles presented here cut across several disciplines ranging from biological function to protein structure to photophysical aspects. These highly original pieces of work include both experimental and computational approaches, and will provide the reader with significant insight into current, state-of-the-art research activities in this very dynamic and fast-paced field. In the first part of this perspective, I will give a brief overview of the history and salient features of GFPs, cite some examples that illustrate their impact on biotechnology, and provide a brief review of the structural and chemical features that lend these proteins their fascinating appearance. In the second part, I will introduce each of the peer-reviewed contributions of the participating authors. [source] Arrays of Electroplated Multilayered Co/Cu Nanowires with Controlled Magnetic AnisotropyADVANCED ENGINEERING MATERIALS, Issue 12 2005R. Pirota The controlled production of arrays of nanowires exhibiting outstanding characteristics is recently attracting much interest owing to their applications in a number of emerging technologies related with multifunctional biosensor applications, controlled optomagnetic response, magnetic storage, magnetotransport, or catalytic performance. While nanolitography methodes require sophisticated experimental facilities, an alternative technique that makes use of much simpler conventional anodization and electrodeposition methods in the fabrication of metallic nanowires arrays is increasingly employed. This method allows the preparation of arrays of highly-ordered nanopores induced by anodisation, and its filling with metallic elements by electrodepositon. [source] Functionalized Self-Assembled InAs/GaAs Quantum-Dot Structures Hybridized with Organic MoleculesADVANCED FUNCTIONAL MATERIALS, Issue 3 2010Miaoxiang Chen Abstract Low-dimensional III,V semiconductors have many advantages over other semiconductors; however, they are not particularly stable under physiological conditions. Hybridizing biocompatible organic molecules with advanced optical and electronic semiconductor devices based on quantum dots (QDs) and quantum wires could provide an efficient solution to realize stress-free and nontoxic interfaces to attach larger functional biomolecules. Monitoring the modifications of the optical properties of the hybrid molecule,QD systems by grafting various types of air-stable diazonium salts onto the QD structures surfaces provides a direct approach to prove the above concepts. The InAs/GaAs QD structures used in this work consist of a layer of surface InAs QDs and a layer of buried InAs QDs embedded in a wider-bandgap GaAs matrix. An enhancement in photoluminescence intensity by a factor of 3.3 from the buried QDs is achieved owing to the efficient elimination of the dangling bonds on the surface of the structures and to the decrease in non-radiative recombination caused by their surface states. Furthermore, a narrow photoluminescence band peaking at 1620,nm with a linewidth of 49 meV corresponding to the eigenstates interband transition of the surface InAs QDs is for the first time clearly observed at room temperature, which is something that has rarely been achieved without the use of such engineered surfaces. The experimental results demonstrate that the hybrid molecule,QD systems possess a high stability, and both the surface and buried QDs are very sensitive to changes in their surficial conditions, indicating that they are excellent candidates as basic sensing elements for novel biosensor applications. [source] Silicon-on-insulator based thin film resistors for quantitative biosensing applicationsPHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 14 2006Petra A. Neff Abstract Field-effect based semiconductor devices for the label-free detection of molecular interactions represent a promising development for biosensor applications. Recently, several such devices have been presented for the direct electrical detection of nucleic acids and proteins. However, a detailed and quantitative understanding of experimental observations is still elusive in most cases. Here we employ a recently introduced Silicon-on-Insulator (SOI) based field-effect sensor for the label-free detection of molecules by their intrinsic charge. We present a theoretical description for the quantitative analysis of the sensor response. A capacitor model was developed which accounts for dielectric effects as well as for Debye screening by mobile ions within the layers of molecules bound to the surface. We successfully applied the model to the detection of charged peptides and multilayers at the functionalized sensor surfaces. The electrical detection of the adsorption of bovine serum albumin (BSA) to the sensor surface is demonstrated and can be explained in terms of a dipolar orientation of the bound molecules. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Dynamics of end grafted DNA molecules and possible biosensor applicationsPHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 14 2006C. Sendner Abstract Polymers that are terminally attached to solid supports, so called brushes, form the basis for a wide variety of different applications in colloidal and biophysical sciences. For grafted charged chains a conducting surface allows to manipulate the brush structure by applying electric fields across the brush. The dynamics of oligomeric DNA molecules under the action of repulsive and attractive surface electric fields is studied by Brownian dynamics simulations including hydrodynamic effects and compared to experimental results. The difference in flexibility between double and single stranded DNA molecules leads to a change in the switching dynamics when repeatedly reversing the surface charge. This effect allows to detect hybridization of surface anchored DNA. Similar kinetic changes occur when other molecules bind terminally to DNA, opening the possibility to use end grafted polymers for general biosensing applications. We in particular discuss the influence of the adsorbate size and change on the switching dynamics. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Controlling the photoluminescence of water-soluble conjugated poly[2-(3-thienyl)ethyloxy-4-butylsulfonate)] for biosensor applicationsPOLYMER INTERNATIONAL, Issue 5 2007Enrique López-Cabarcos Abstract The photoluminescence of poly[2-(3-thienyl)ethyloxy-4-butylsulfonate)] (PTE-BS) in aqueous solution increases threefold on addition of the surfactant tetrabutylammonium perchlorate (TBA). Furthermore, the luminescence of the PTE-BS/TBA system is reduced by more than five times by the addition of small amounts of the cationic electron acceptor methyl viologen (MV2+). The Stern,Volmer constant KSV = 1.4 × 104 L mol,1 for the quenching of the polymer,surfactant complex by MV2+ is approximately 60 times smaller than the KSV = 8.4 × 105 L mol,1 obtained in water polymer solutions without surfactant. Thus, the luminescence of PTE-BS in aqueous solution can be modulated by complexing the polymer either with a surfactant or with a quencher. In this contribution we show that the surfactant/quencher tuning effect found in polymers of the phenylenevinylene family, such as poly(2,5-methoxy-propyloxysulfonate phenylenevinylene), also appears in polymers of the thiophene family such as PTE-BS. Copyright © 2007 Society of Chemical Industry [source] Surface plasmon resonance label-free monitoring of antibody antigen interactions in real timeBIOCHEMISTRY AND MOLECULAR BIOLOGY EDUCATION, Issue 1 2007Asta Kausaite Abstract Detection of biologically active compounds is one of the most important topics in molecular biology and biochemistry. One of the most promising detection methods is based on the application of surface plasmon resonance for label-free detection of biologically active compounds. This method allows one to monitor binding events in real time without labeling. The system can therefore be used to determine both affinity and rate constants for interactions between various types of molecules. Here, we describe the application of a surface plasmon resonance biosensor for label-free investigation of the interaction between an immobilized antigen bovine serum albumin (BSA) and antibody rabbit anti-cow albumin IgG1 (anti-BSA). The formation of a self-assembled monolayer (SAM) over a gold surface is introduced into this laboratory training protocol as an effective immobilization method, which is very promising in biosensing systems based on detection of affinity interactions. In the next step, covalent attachment via artificially formed amide bonds is applied for the immobilization of proteins on the formed SAM surface. These experiments provide suitable experience for postgraduate students to help them understand immobilization of biologically active materials via SAMs, fundamentals of surface plasmon resonance biosensor applications, and determination of non-covalent biomolecular interactions. The experiment is designed for master and/or Ph.D. students. In some particular cases, this protocol might be adoptable for bachelor students that already have completed an extended biochemistry program that included a background in immunology. [source] Stabilization of glucose oxidase in alginate microspheres with photoreactive diazoresin nanofilm coatingsBIOTECHNOLOGY & BIOENGINEERING, Issue 1 2005Rohit Srivastava Abstract The nanoassembly and photo-crosslinking of diazo-resin (DAR) coatings on small alginate microspheres for stable enzyme entrapment is described. Multilayer nanofilms of DAR with poly(styrene sulfonate) (PSS) were used in an effort to stabilize the encapsulation of glucose oxidase enzyme for biosensor applications. The activity and physical encapsulation of the trapped enzyme were measured over 24 weeks to compare the effectiveness of nanofilm coatings and crosslinking for stabilization. Uncoated spheres exhibited rapid loss of activity, retaining only 20% of initial activity after one week, and a dramatic reduction in effective activity over 24 weeks, whereas the uncrosslinked and crosslinked {DAR/PSS}-coated spheres retained more than 50% of their initial activity after 4 weeks, which remained stable even after 24 weeks for the two and three bilayer films. Nanofilms comprising more polyelectrolyte layers maintained higher overall activity compared to films of the same composition but fewer layers, and crosslinking the films increased retention of activity over uncrosslinked films after 24 weeks. These findings demonstrate that enzyme immobilization and stabilization can be achieved by using simple modifications to the layer-by-layer self-assembly technique. © 2005 Wiley Periodicals, Inc. [source] | |||||||||||||