Enzyme-responsive multifunctional surfaces for controlled uptake/release of (bio)molecules.

The current trend in the development of biomaterials is towards bioactive and biodegradable systems. In particular, enzyme-responsive structures are useful tools to realize biodegradable surfaces for the controlled delivery of biomolecules/drugs through a triggered surface erosion process. Up to now, enzyme-responsive structures have been designed by covalent linkage between synthetic polymers and biodegradable functionalities that are responsive to chemical and biological cues (i.e. proteases or pH) [1-4]. Here, we present a novel approach to achieve enzyme-responsive surface-attached networks by exploiting the non-covalent interaction between streptavidin and biotin. The functional component of this three-dimensional (3D) structure is a layer of biotinylated peptides that are degraded by the action of specific proteases. The system was stable under typical physiological conditions; however, it was efficiently degraded upon enzyme exposure. Further, the controlled release of biomolecules and drugs--previously entrapped into the surface-attached network--was demonstrated to occur as a consequence of the enzymatic cleavage. This versatile approach does not require complex chemical procedures. Interestingly, it can be easily adapted to different enzyme-peptide partners and therefore is very attractive for tissue replacement, drug delivery and biosensing.