Biomimetic click assembled multilayer coatings exhibiting responsive properties

Abstract

Stimuli-responsive polymers are capable of changing their physico-chemical properties in a dynamic way, to respond to variations on the surrounding environment. These materials have gained increasingly importance for different areas, such as drug delivery, biosensors, microelectronic systems and also for the design and modification of biomaterials to apply on tissue engineering field. In the last years, different strategies have been envisaged for the development of stimuli-responsive biomaterials. Layer-by-layer (LbL) is a promising and versatile technique to modify biomaterials' surfaces, and has allowed tailoring interactions with cells. In this study, LbL is used to construct biomimetic stimuli-responsive coatings using elastin-like recombinamers (ELRs). The recombinant nature of ELRs provides the ability to introduce specific bioactive sequences and to tune their physicochemical properties, making them attractive for biomedical and biological applications. By using complementary clickable ELRs, we were able to construct multilayer coatings stabilized by covalent bonds, resulting from the Huisgen 1,3-dipolar cycloaddition of azides and alkynes. Herein, we exploited the switchable properties of the ELRs-based coatings which are dependent on lower critical solution temperature (LCST) transition. Above LCST, the polymers collapsed and nanostructured precipitates were observed on the surface's morphology, increasing the water contact angle. Also, the influence of pH on prompting reversible responses on coatings was evaluated. Finally, in vitro cell studies using a C2C12 myoblastic cell line were performed to perceive the importance of having bioactive domains within these coatings. The effect of RGD incorporation is clearly noted not only in terms of adhesion and proliferation but also in terms of myoblast differentiation.