Fabrication of honeycomb films from highly functional dendritic structures: electrostatic force driven immobilization of biomolecules

Herein we report the preparation of honeycomb porous films for selective immobilization of biomolecules via the breath figure technique, a water-assisted micropatterning method. In particular, porous films are obtained from polymeric blends composed of high molecular weight polystyrene as the major component and an oligoglycerol based dendron covalently bonded to a hydrophobic polystyrene chain as the minor constituent. The multivalent dendritic architecture presents a well-defined molecular structure with controlled glycine arrays on their surfaces. Due to the mechanism of the breath figure formation, the resulting films exhibit an especial chemical distribution at the surfaces, in which the dendritic functional polymer is located preferentially in the interior of the pores while the rest of the polymer surface is mainly formed by the high molecular weight polystyrene. The high amount of amine functional groups inside the pores allowed the specific immobilization of biomolecules into the cavities by electrostatic interactions. In particular, the protein bovine serum albumin (BSA) and a DNA sequence were attached onto the films as a proof of concept. Besides, it was demonstrated that the density of biomolecules immobilized can be easily tuned by varying the content of the dendritic functional polymer in the film. These unique characteristics open new alternatives for the use of these platforms in biorelated applications including bio-recognition processes, or the understanding of cell–protein and even cell–DNA interactions on biofunctional microstructured polymeric supports.