Adhesive-inspired Polymers

The third and last section of our book deals with polymeric materials with bio-inspired functionality. The opening chapter by Waite gives a biological perspective of how mussels adhere to interfaces and emphasizes the importance of first understanding the biology before new, tmly bio-inspired materials can be achieved. The second chapter in this section, written by Lee, describes the synthetic achievements of mussel glue-inspired polymers, and depicts the polymer chemist s approach to mimic the mussel adhesion described by Waite in the previous chapter. Bruns and co-authors present a chapter on self-reporting polymeric materials with mechanochromic properties. Such materials mimic nature s ability to report, repair, and improve... 

Lee BP, Dalsin JL, Messersmith PB (2006) Biomimetic adhesive polymers based on mussel adhesive proteins. In Smith AM, Callow JA (eds) Biological adhesives. Springer, Berlin/Heidelberg, pp 257-278 Lee H, Lee BP, Messersmith PB (2007) A reversible wet/ dry adhesive inspired by mussels and geckos. Nature 448 338-341... 

Major new insights into the surface science of silicone materials were catalyzed by the work of deGennes, whose theories of polymer wetting and adhesion have inspired many to explore his provocative themes [7]. These explorations focused attention on the need for a polymeric material that is well characterized, liquid over a wide molecular weight range, with controlled molecular weight distribution and crosslinkable in a controlled fashion. Dimethylpolysiloxane is the best available candidate and has become central to a revolution in polymer surface physics. 

An alternative approach to immobilize organic compounds such as MPC to metal substrates is the use of mussel-inspired chemistry. Mussels can rapidly and permanently adhere to all types of inorganic and organic surfaces in aqueous environments. Such adhesive properties rely on repeats of the 3,4-dihydro)q7-L-phenylalanine (DOPA) motif found in the foot protein of mussels. Although the exact mechanism of adhesion is not fully understood, it has been widely speculated that the 3,4-dihydro)qq3henyl (DHP) group of DOPA is responsible for the adhesion. When a polymer with DHP groups was placed in contact with a metal substrate, a thin polymer film was observed to spontaneously deposit on the surface. Functionalization of such a polymer was then able to impart new characteristics to the metal substrate. 

Biomimetics is an important strategy for the fabrication of modern biomaterials that provides solutions which closely resemble those of living systems. In the area of biomimetic supramolecular chemistry, a surface-grafted PMOEP polymer has recently been found to impart mesoporous silica with switchable ion channel transport properties. This was enabled by the dual protonation and Ca chelation ability of the polymer phosphate groups. A series of studies made use of PMAEP-based copolymers in the fabrication of biomimetic adhesives which were inspired by the sandcastle worm that produces peptide polyelectrolytes rich in phosphorylated serine. These adhesives were aimed at providing molecular solutions to... 

A more recent example of a biotransformation of peptide-polymer conjugates combines biocombinatorial procedures with enzjonatic activation processes in order to realize mussel-glue inspired adhesion. Phage-display biopanning incorporating tyrosinase to transform L-tyrosine residues to L-dopa enabled the direct selection of enzymatically activable 12-mer peptide adhesion domains for aluminum oxide (Figure 1.21). 

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