Substrate-independent layer-by-layer assembly by using mussel-adhesive- inspired polymers

A study was conducted to demonstrate that a synthetic catecholamine polymer, influenced by by mussel adhesive protein absorbs to all surfaces and can serve as a platform for layer-by-layer (LbL) assembly in a surface-independent manner. Poly(ethylenimine) (PEI), a cationic polymer, was conjugated with 3-(3,4-dihydroxyphenyl)propionic acid, to make catechol-functionalized PEI (PEI-C). It was observed that the degree of catechol modification in PEI-C is 63%, as determined by the ninhydrin test, preserving the cationic character of the polymer for use in LbL, while mimicking the high catechol content of mussel adhesive proteins at the same time. The study also demonstrated that hyaluronic acid (HA), a linear polysaccharide, was selected for an anionic polymer.