Polymeric layer-by-layer films composed by natural polymers and based on the adhesive properties of mussels for biomedical applications

Some marine species, such as mussels, can strongly attach themselves to rocks in the diffficult conditions of the sea. In fact, marine mussels secrete adhesive proteins that show a high adhesion to both inorganic and organic surfaces in aqueous environments. These proteins have an amino acid designated as 3,4-dihydroxy-L-phenylalanine (DOPA) which in turn possesses catechol groups that are primarily responsible for these strong adhesive bonds. Inspired by this behaviour, layer-by- layer (LbL) films based on polymers that contain catechol groups were developed. It is expected that such materials will present an enhanced cell adhesion when they are applied in biomedical applications. Dopa- mine-modified hyaluronic acid (HA-DN), which possesses catechol groups, was prepared by carbodiimide chemistry. This conjugate was characterized by distinct techniques, such as nuclear magnetic reso- nance (NMR) and ultra-violet spectrophotometry (UV). Then films were developed based on chitosan (CHT) and HA-DN using the Layer- by-Layer (LbL) technique. The formation of these films was investi- gated in-situ by quartz crystal microbalance with dissipation monitoring (QCM-D). The adhesion properties of the coatings were also analyzed. In vitro tests using distinct cell sources revealed an enhanced cell adhe- sion, proliferation and viability for the films that contain catechol groups, which demonstrates their potential to be used in biomedical applications.