Trends in biotechnology

Ecological risk assessment for transgenic crops: separating the seed from the chaff.

Publication Date: 2010 Feb 1 PMID: 20129685
Authors: Herman, R. A.
Journal: Trends Biotechnol

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Classification of osseointegrated implant surfaces: materials, chemistry and topography.

Publication Date: 2010 Jan 28 PMID: 20116873
Authors: Dohan Ehrenfest, D. M. - Coelho, P. G. - Kang, B. S. - Sul, Y. T. - Albrektsson, T.
Journal: Trends Biotechnol

Since the founding of the osseointegration concept, the characteristics of the interface between bone and implant, and possible ways to improve it, have been of particular interest in dental and orthopaedic implant research. Making use of standardized tools of analysis and terminology, we present here a standardized characterization code for osseointegrated implant surfaces. This code describes the chemical composition of the surface, that is, the core material, such as titanium, and its chemical or biochemical modification through impregnation or coating. This code also defines the physical surface features, at the micro- and nanoscale, such as microroughness, microporosity, nanoroughness, nanotubes, nanoparticles, nanopatterning and fractal architecture. This standardized classification system will allow to clarify unambiguously the identity of any given osseointegrated surface and help to identify the biological outcomes of each surface characteristic.

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Polyblend nanofibers for biomedical applications: perspectives and challenges.

Publication Date: 2010 Jan 28 PMID: 20116113
Authors: Gunn, J. - Zhang, M.
Journal: Trends Biotechnol

Advances in disease treatment and tissue regeneration are buoyed by new, multifaceted materials that emulate and coercively interact with the local microenvironment. Polyblend nanofibers represent an emerging class of biomimetic nanostructures that can act as proxies of the native tissue, while providing topographical and biochemical cues that promote healing. These fibers are prepared with mixtures of synthetically and naturally derived polymers that can behave cooperatively to demonstrate unique combinations of mechanical, biochemical and structural properties. This flexibility has led to the application of polyblend nanofibers in a wide assortment of tissue engineering and drug delivery systems. In this review, we will examine design criteria and properties of polymer-blend nanofibers and their use in tissue engineering and local therapeutic delivery applications.

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Ultraslow microdialysis and microfiltration for in-line, on-line and off-line monitoring.

Publication Date: 2010 Jan 14 PMID: 20079945
Authors: Korf, J. - Huinink, K. D. - Posthuma-Trumpie, G. A.
Journal: Trends Biotechnol

In medicine and biotechnology, close monitoring of molecular processes might assist to optimise therapeutic interventions and production of biochemicals, respectively. Here, we summarize the current status of two automatic and continuous sampling technologies, microdialysis and microfiltration, which facilitate both in vivo and in vitro monitoring of nearly any analyte, because they can be combined easily with many analytical techniques. Conventional microdialysis and microfiltration, which require collecting relatively large samples, are however often impractical and semi-quantitative; hence, we focus on ultraslow sampling to circumvent such limitations. Ultraslow microdialysis and microfiltration already have been used successfully for quantitative pharmacokinetics, glucose metabolism (e.g. of the brain), cytokines and proteomics (e.g. tumour secretomes), both in vivo and in vitro.

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Frontiers in Cancer Nanomedicine: Directing Mass Transport through Biological Barriers.

Publication Date: 2010 Jan 13 PMID: 20079548
Authors: Ferrari, M.
Journal: Trends Biotechnol

The physics of mass transport within body compartments and across biological barriers differentiates cancers from healthy tissues. Variants of nanoparticles can be manufactured in combinatorially large sets, varying by only one transport-affecting design parameter at a time. Nanoparticles can also be used as building blocks for systems that perform sequences of coordinated actions, in accordance with a prescribed logic. We refer to these as Logic-Embedded Vectors (LEVs). Nanoparticles and LEVs are ideal probes for the determination of mass transport laws in tumors, acting as imaging contrast enhancers, and can be employed for lesion-selective delivery of therapy. Their size, shape, density and surface chemistry dominate convective transport in the bloodstream, margination, cell adhesion, selective cellular uptake, as well as sub-cellular trafficking and localization. As argued here, the understanding of transport differentials in cancer, termed 'transport oncophysics', reveals a promising new frontier in oncology: the development of lesion-specific delivery particulates that exploit mass transport differentials to deploy treatment of greater efficacy and reduced side effects.

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Functionalised gold nanoparticles for controlling pathogenic bacteria.

Publication Date: 2010 Jan 11 PMID: 20071044
Authors: Pissuwan, D. - Cortie, C. H. - Valenzuela, S. M. - Cortie, M. B.
Journal: Trends Biotechnol

The increasing number of bacterial strains that are resistant to available pharmaceutical compounds is a vital issue for public health. Innovative approaches will be required to improve the methods for both diagnosis and destruction of these organisms. Here, we consider the possible role that can be played by technologies based on gold nanoparticles. Gold nanoparticles generally are considered to be biologically inert but can be engineered to possess chemical or photothermal functionality. A growing body of research is devoted to the potential use of these nanoparticles in the diagnosis and treatment of bacterial infections. The results are both promising and intriguing, and suggest a range of new strategies to identify, target or destroy pathogenic organisms.

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Musculoskeletal molecular imaging: a comprehensive overview.

Publication Date: 2010 Feb PMID: 20045210
Authors: Reumann, M. K. - Weiser, M. C. - Mayer-Kuckuk, P.
Journal: Trends Biotechnol

Molecular imaging permits non-invasive visualization and measurement of molecular and cell biology in living subjects, thereby complementing conventional anatomical imaging. Herein, we review the emerging application of molecular imaging for the study of musculoskeletal biology. Utilizing mainly bioluminescence and fluorescence techniques, molecular imaging has enabled in-vivo studies of (i) the activity of osteoblasts, osteoclasts, and hormones, (ii) the mechanisms of pathological cartilage and bone destruction, (iii) skeletal gene and cell therapy with and without biomaterial support, and (iv) the cellular processes in osteolysis and osteomyelitis. In these applications, musculoskeletal molecular imaging demonstrated feasibility for research in a myriad of musculoskeletal conditions ranging from bone fracture and arthritis to skeletal cancer. Importantly, these advances herald great potential for innovative clinical imaging in orthopedics, rheumatology, and oncology.

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Forisomes: calcium-powered protein complexes with potential as 'smart' biomaterials.

Publication Date: 2010 Feb PMID: 20004992
Authors: Tuteja, N. - Umate, P. - van Bel, A. J.
Journal: Trends Biotechnol

Sieve tubes in legumes contain forisomes, which are spindle-like bodies that are composed of ATP-independent, mechanically active proteins. Upon injury, forisomes occlude sieve tubes by dispersion and thus, help to prevent loss of nutrient-rich transport sap. Forisome enlargement by dispersion is brought about by Ca2+-induced conformational changes that confer radial expansion and longitudinal contraction. Forisomes recontract upon Ca2+ removal. In vitro, forisomes reversibly disperse and contract in the presence or absence of Ca2+, respectively, and at distinct pHs. Recently, forisomes have received renewed attention because of their unique capacity to convert chemical into mechanical energy independent of high-energy organic compounds. Forisome-based 'smart' materials can be used to produce self-powered monitoring and diagnostic systems. Here, we focus on physiological, chemical and physical aspects of forisomes and discuss their potential as biomimetic devices.

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Designer laccases: a vogue for high-potential fungal enzymes?

Publication Date: 2010 Feb PMID: 19963293
Authors: Rodgers, C. J. - Blanford, C. F. - Giddens, S. R. - Skamnioti, P. - Armstrong, F. A. - Gurr, S. J.
Journal: Trends Biotechnol

Laccases are blue multicopper oxidases that catalyse the four-electron reduction of O(2) to water coupled with the oxidation of small organic substrates. Secreted basidiomycete white-rot fungal laccases orchestrate this with high thermodynamic efficiency, making these enzymes excellent candidates for exploitation as industrial oxidants. However, these fungi are less tractable genetically than the ascomycetes, which predominantly produce lower-potential laccases. We address the state-of-play regarding expression of high reduction potential laccases in heterologous hosts, and issues regarding enzyme glycosylation status. We describe the synergistic role of structural biology, particularly in unmasking structure-function relationships following genetic modification and their collective impact on laccase yields. Such recent research draws closer the prospect of industrial quantities of designer, fit-for-purpose laccases.

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Nanofiber micelles from the self-assembly of block copolymers.

Publication Date: 2010 Feb PMID: 19962775
Authors: Qian, J. - Zhang, M. - Manners, I. - Winnik, M. A.
Journal: Trends Biotechnol

Micelles are formed when block copolymers are dissolved in solvents selective for one of the blocks. In contrast to micelles formed by surfactants, block copolymer micelles are generally more robust, and this opens the door to many applications. This article examines the formation and structure of fiber-like or filamentous micelles, with cross-sections of nanometer dimensions. These fascinating objects are currently under investigation for drug delivery applications, as impact modifiers for plastics, as templates for the deposition of metal nanoparticles and as precursors to nanoscale ceramics. Moreover, in some cases, studies of their formation and fragmentation are beginning to provide insight into the generation of protein fibers, such as actin or amyloid fibers, derived from soluble cytosolic protein precursors.

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Monitoring protein interactions and dynamics with solvatochromic fluorophores.

Publication Date: 2010 Feb PMID: 19962774
Authors: Loving, G. S. - Sainlos, M. - Imperiali, B.
Journal: Trends Biotechnol

Solvatochromic fluorophores possess emission properties that are sensitive to the nature of the local microenvironment. These dyes have been exploited in applications ranging from the study of protein structural dynamics to the detection of protein-binding interactions. Although the solvatochromic indole fluorophore of tryptophan has been utilized extensively for in vitro studies to advance our understanding of basic protein biochemistry, the emergence of new extrinsic synthetic dyes with improved properties, in conjunction with recent developments in site-selective methods to incorporate these chemical tools into proteins, now open the way for studies in more complex systems. Herein, we discuss recent technological advancements and their application in the design of powerful reporters, which serve critical roles in modern cell biology and assay development.

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Single cells as experimentation units in lab-on-a-chip devices.

Publication Date: 2010 Feb PMID: 19914725
Authors: Le Gac, S. - van den Berg, A.
Journal: Trends Biotechnol

'Lab-on-a-chip' technology (LOC) has now reached a mature state and is employed commonly in research in the life sciences. LOC devices make novel experimentation possible while providing a sophisticated environment for cellular investigation. As a next step, we introduce here the concept of a 'lab-in-a-cell': the use of a single cell as a minimal and highly confined experimental unit, or experimentation in the simple, but still unequalled, platform provided by nature itself. LOC provides the appropriate format and set of tools for LIC experimentation, and we discuss here three types of LIC investigation: the elucidation of signaling pathways; the creation of novel production units; and the use of microfluidics for assisted reproduction techniques.

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