biomimetic nanomaterials otherwise biomimetics; bioinspired materials (rus. наноматериалы, биомиметические otherwise биомиметики) — artificial nanomaterials imitating properties of biomaterials or designed using biological principles.

Description

Reference to biological models inspiring engineers to develop new materials and technologies is based on the assumption that nature, in many billion years of evolution, has created optimal living structures that are far more effective and endurable than any man-made structures. For example, the study of the “lotus effect” , i.e. the property of lotus leaves to resist wetting and dirt due to their micro- and nanostructured surface has led to the development of waterproof paints and textiles. Polymer nanofibres whose strength is comparable to that of steel were inspired by an example from biology, namely the cobweb whose threads can withstand three times greater strain than steel wire with equal diameter. Burdock fruit became a prototype for the synthetic adhesive material Velcro, the basis of widely used hook-and-loop fasteners.

Many biomolecules are capable of self-assembly in regular structures. For example, under polymerisation conditions the contractile protein actin forms filaments 7 nm thick, and tubulin forms microtubes 25 nm in diameter. Using this self-assembling mechanism and the biostructures as matrices , nanoconductors and nanotubes can be created through the deposition of metal monolayers onto biopolymers. Complementarity that underlies the double-stranded DNA assembly is used in the development of new DNA-based nanomaterials.

Knowing the structure and functions of biological molecules, we can synthesise hybrid molecules, including peptides, lipids and organic polymers, and develop biomimetic nanofibres, bioinorganic composites and nanoporous coatings for tissue engineering.

Biomimetic nanoparticles are under active development. For example, ferritin, a protein that transports and stores iron in an organism, forms nanocavities with an inner diameter of 8 nm. Magnetic nanoparticles of iron oxide and cobalt oxide with a mean size of 6 nm can be encapsulated in these nanocavities. Other approaches employ “growing” nanoparticles of specific sizes inside bacteria or the biomass of plants (oats, wheat or alfalfa). Metal salts are added to these biological objects, and after biocatalitic reduction to metals they form nanoparticles. Methods of growing metallic nanoparticles in plants by adding metal salts to the irrigation water have been described. Nanoparticles are formed in the stems and other parts of plants and can be extracted. Proteins involved in reducing reactions define the size of the formed nanoparticles. In some cases peptide sequences responsible for catalysis have been identified, which allowed them to be used as ring peptides for the in vitro development of nanoparticles. Nanoparticles can also be created using viral shells (capsids). Viral capsid proteins are assembled to form regular-shaped three-dimensional structures with a hollow space inside where the virus genome is packed. High regularity calibrated metallic nanoparticles and nanocomposites can be assembled both inside a capsid and on its surface. Biomimetic synthesis of nanoparticles has certain advantages; for example, it is carried out under milder conditions compared to the physical and chemical production of nanoparticles. In the large-scale production of nanoparticles this feature makes it possible to minimise adverse environmental effects.

Author

  • Shirinsky Vladimir P.

Sources

  1. Ma P. X. Biomimetic Materials for Tissue Engineering // Adv. Drug Deliv. Rev. 2008. V. 60. P. 184–198.
  2. Nanomaterials for the Life Sciences. V. 2: Nanostructured Oxides Ed. by Kumar, Challa S. S. R. — Weinheim: Wiley–VCH, 2009. — 507 p.

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