Bioinspired adhesive

Biomimetic adhesives are synthetic adhesives designed to closely mimic the molecular structure and mechanisms of adhesion found in nature. Bioinspired adhesives are synthetic adhesives whose design is inspired in biological concepts, mechanisms, functions, and design features. The aim is not to emulate any particular biological architecture or system, but to use such knowledge as a source of guiding principles and ideas. 

Nature is indeed a school for materials science and its associated disciplines such as chemistry, biology, physics, or engineering. Biomimetic and bioinspired adhesives are being designed to take advantage of the many inspiring properties of materials found in nature, such as sophistication, miniaturization, hierarchical organizations, hybridation, resistance, and adaptability. 

The nanostructured surfaces resemble, at least to a certain degree, the architecture of physiological adhesion substrates, such as extracellular matrix, which is composed from nanoscale proteins, and in the case of bone, also hydroxyapatite and other inorganic nanocrystals [16,17,24-27]. From this point of view, carbon nanoparticles, such as fullerenes, nanotubes and nanodiamonds, may serve as important novel building blocks for creating artificial bioinspired nanostructured surfaces for bone tissue engineering. 

Sailaja GS, Sreenivasan K, Yokogawa Y, Kumary TV, Varma HK (2009) Bioinspired mineralization and cell adhesion on surface functionalized poly(vinyl alcohol) films. Acta Biomater 5 1647-1655... 

To avoid the limitations of native bonding agents, adhesives based on biomimetic approaches are being developed. These bioinspired molecules are generated either by recombinant protein production (Rodrigues et al., 2014) or by chemically... 

Alternatively, tree frogs could offer a valid solution for wet and reversible adhesion (Scholz et al., 2009). Their pads consist of regularly arrayed nanopillars of 300—400-pm diameters (Fig. 2.3(d)). Randomly distributed within the array are wide pores that secrete a mucus layer. To date, their properties and roles remain unclear. Wet adhesion is suggested to be attained by a combination of capillary, friction, and viscous forces. However, the entire mechanism by which the tree frog succeeds in adhesion under wet conditions remains uncertain. Therefore, reversible bioinspired wet adhesives are stiU much less advanced in their development than their dry adhesive counterpart. 

For tile fabrication of interfaces with precise control of cell adhesion, the NITEC conjugation protocol was combined with the resistance of poly(oligoethylene glycol methyl ether metiiacrylate) (poly(MeOEGMA)) brushes and the versatility of bioinspired PDA surfaces (see Figure 9.7). 

Greiner, C., del Campo, A., and Arzt, E. (2007) Adhesion of bioinspired micropattemed surfaces Effects of pillar radius, aspect ratio, and preload. Lar muir, 23, 3495—3502. 

Colloidal crystal polymers also have been used as templates for bioinspired materials. Geckos use closely packed arrays of hairs to create adhesion. The hairs can be scalably mimicked using colloidal crystal monolayers on silica substrates [149,150], The voids created by the PS colloid were etched to create nanotrenches in the substrate which, following dissolution of the polymer colloid, were filled with parylene. Subsequently the silica was removed, leaving a free-standing flexible parylene pillar array with enhanced adhesive properties. 

Hefer A, Little D (2005) Adhesion in bitumen-aggregate systems and quantifications of the effects of water on the adhesive bond, http //www.icar.utexas.edu/ reports/505 l.pdf, Texas A M University Jagota A, Hui CY, Glassmaker NJ, Tang T (2007) Mechanics of bioinspired and biomimetic fibrillar interfaces. MRS Bull 32 492-i95... 

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