What is the current state of nanoscience And nanotechnology?

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  • #1175514
    Meric
    Katılımcı

      What is the current state of nanoscience and
      nanotechnology?
      Current knowledge in nanoscience comes from developments in
      chemistry, physics, life sciences, medicine, and engineering. Nanotechnology is
      under active development or already in practical use in several areas:
      In materials science, nanoparticles allow for the making of
      products with new mechanical properties, including surface friction, wear
      resistance, and adhesion.
      The smallest components of a computer chip are on a
      nanoscale.
      The smallest components of a computer chip are on a
      nanoscale.
      Credit: NanoPrism Technologies, Inc.In biology and medicine, nanomaterials are used to improve
      drug design and targeting. Others are being developed for analytical and
      instrumental applications.
      Consumer products such as cosmetics, sunscreens, fibres,
      textiles, dyes, and paints already contain nanoparticles.
      In electronic engineering, nanotechnologies are used for
      instance to design smaller, faster, and less consuming data storage devices.
      Optical devices such as microscopes have also benefited from
      nanotechnology.
      Current knowledge of science at the nanoscale comes from
      developments in disciplines such as chemistry, physics, life sciences, medicine
      and engineering. There are several areas in which nanoscale structures are
      under active development or already in practical use:
      In materials science, nanoparticles allow for the making of
      products with mechanical properties very different from those of conventional
      materials and can also improve surfaces by adding new friction, wear or
      adhesion properties.
      In biology and medicine, a greater understanding of the
      functioning of molecules and of the origin of diseases on the nanometre scale
      has lead to improvements in drug design and targeting. Nanomaterials are also
      being developed for analytical and instrumental applications, including tissue
      engineering and imaging.
      A wide variety of nanoscale materials and coatings are
      already in use in consumer products such as cosmetics and sunscreens, fibres
      and textiles, dyes, and paints.
      The smallest components of a computer chip are on a
      nanoscale.
      The smallest components of a computer chip are on a
      nanoscale.
      Credit: NanoPrism Technologies, Inc.The constant drive towards miniaturization in electronic
      engineering has led to devices that are well within the nanometre range. Data
      storage devices based on nanostructures provide smaller, faster, and lower
      consumption systems.
      Optical devices have also benefited from this trend and new
      types of microscopes have been invented, that can produce images of atomic and
      molecular processes at surfaces. More…
      3.3 Nanoscience
      and Nanotechnology
      3.3.1 Introduction Current knowledge
      of science at the nanometre scale is derived from many disciplines, originating
      with the atomic and molecular concepts in chemistry and physics, and then
      incorporating molecular life sciences, medicine and engineering. The
      observation and understanding of atomic and molecular behaviour from first
      principles was followed by the increasing ability to control and selectively
      modify properties of ever smaller pieces of matter in a functional way. Early
      examples here are the discoveries in self assembly (Bain et al 1989) which
      culminated in current synthetic and supra-molecular chemistry (Lehn 1988, Gomez
      –Lopez et al 1996), the increasing knowledge about life’s replication processes
      and the co-evolution of physical (Perutz et al 1960, Aue et al 1976, Wuthrich
      1995) and chemical methodologies. These have resulted in the portfolio of
      current molecular life sciences such as molecular motors and other functional
      entities (Mavroidis et al 2004, Clark et al 2004), including biomolecular and
      medical engineering and the emerging area of systems biology. On the other
      hand, man made micro and nanoscale sensing devices originate from other domains
      in microscopy and device engineering but relate to biomedical applications
      (Ziegler 2004, Emerich and Thanos 2003).
      The deviation of
      surface and interface properties from the bulk properties of larger amounts of
      materials led to the sometimes unexpected significance of surface effects,
      including catalytic activity and wetting behaviour in material composed of
      nanosized entities, such as nanoparticles, composites and colloids (Kamat 2002,
      Schwerdtfeger 2003). Quantum mechanical principles manifest themselves in the
      properties of surfaces of clusters of very small particles, especially those of
      the order of 1000 atoms or molecules and less. Composite materials (Komarneni
      1992, Schmidt 2000, Hadjipanayis 1999), with increasingly smaller
      characteristic sizes of the domains or phases, allowed for the design of
      materials with new and optimised physical and / or chemical properties. In
      electronic engineering, the miniaturization of devices has progressed well into
      the nanometre range with gate oxides in devices being routinely 25 nm thick.
      The recently increased public awareness of nanoscience is closely related to
      the availability of first real space images of atomic and molecular processes
      at surfaces through the invention of Scanning Probe Microscopies (Binnig and
      Rohrer 1985).
      With the
      continuous development of nanotechnology, the possibility for the bottom-up
      production of nanoscale materials may result in some kind of self assembly of
      structures similar to the self assembly of phospholipid bilayers that resembles
      cellular membranes.
      On the basis of
      current knowledge however, the spontaneous formation of artificial living
      systems through self assembly and related processes, suggested by some
      prominent commentators, is considered highly improbable. The combination of
      self replication with self perpetuation in an engineered nanosystem is
      extremely difficult to realize on the basis of current scientific knowledge.
      3.3.2 Examples of
      Engineered Nanostructures and Materials and Their Applications
      There are several
      areas of science and technology in which nanoscale structures are under active
      development or already in practical use.

      #1740426
      Meric
      Katılımcı

        In materials
        science, nanocomposites with nanoscale dispersed phases and nanocrystalline
        materials in which the very fine grain size affords quite different mechanical
        properties to conventional microstructures are already in use. In surface
        science and surface engineering, nanotopographies offer substantially different
        properties related to adhesion, tribology, optics and electronic behaviour.
        Supramolecular chemistry and catalysis have led to novel surface and size
        dependent chemistry, such as enantioselective catalysis at surfaces. In
        biological sciences, fundamental understanding of molecular motors and
        molecular functional entities on the nanometre scale has been responsible for
        advances in drug design and targeting. Nanoscale functionalised entities and
        devices are in development for analytical and instrumental applications in
        biology and medicine, including tissue engineering and imaging.
        The application
        areas in which these advances in nanoscience are making their biggest impact
        include electronic, electro-optic and optical devices. The transition from
        semiconductor (conventional and organic) technology to nanoscale devices has
        anticipated improved properties and resolution, e.g. fluorescence labelling,
        scanning probe microscopy and confocal microscopy. Data storage devices based
        on nanostructures provide smaller, faster, and lower consumption systems.
        In medicine,
        greater understanding of the origin of diseases on the nanometre scale is being
        derived, and drug delivery through functionalised nanostructures may result in
        improved pharmacokinetic and targeting properties.
        A wide variety of
        functional nanoscale materials and functional nanoscale surfaces are in use in
        consumer products, including cosmetics and sunscreens, fibres and textiles,
        dyes, fillers, paints, emulsions and colloids.
        Source & ©: SCENIHR
        The appropriateness of existing methodologies to assess the potential
        risks associated with engineered and adventitious products of nanotechnologies
        (2006),
        3.3 Nanoscience and Nanotechnology, p. 11 3.3.4 Nanoscale
        materials properties
        Material
        properties depend on structure and composition, and can typically be engineered
        or modified by changing the relative influence of interfacial or interphase
        properties and the macroscopic bulk properties through the characteristic size
        or dimension of components and domains. This approach had already emerged
        centuries ago with steel alloys and has been so powerful that many engineering
        materials today are composites with micro to nanoscale domain sizes. Depending
        on the physical or chemical character of each domain, there is a complex
        interrelation between the structure and the composition of the material, which
        may relate to the bulk and surface properties of each ingredient and newly
        emerging properties localized at the interface. selective chemical reactivity
        is quite common with nanocomposites, which gives the potential for
        disintegration of the material into one or the other component. Complex
        processes govern this behaviour, which clearly relates to nanoparticle release
        into the environment.
        3.3.5 Conclusions. The exploitation
        of the properties associated with the nanoscale is based on a small number of
        discrete differences between features of the nanoscale and those of more
        conventional sizes, namely the markedly increased surface area of nanoparticles
        compared to larger particles of the same volume or mass, and also quantum
        effects. Questions naturally arise as to whether these features pose any
        inherent threats to humans and the environment. Bearing in mind that naturally
        occurring processes, such as volcanoes and fires, in the environment have been
        generating nanoparticles and other nanostructures for a very long time, it
        would appear that there is no intrinsic risk associated with the nanoscale per
        se for the population as a whole. As noted above, there is also no reason to
        believe that processes of self assembly, which are scientifically very
        important for the generation of nanoscale structures, could lead to
        uncontrolled self perpetuation. The real issues facing the assessment of risks
        associated with the nanoscale are largely concerned with the increased exposure
        levels, of both humans and environmental species, now that engineered
        nanostructures are being manufactured and generated in larger and larger
        amounts, in the new materials that are being so generated, and the potentially
        new routes by which exposure may occur with the current and anticipated
        applications.

        #1742751
        semra
        Katılımcı

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