Block Copolymers-Based Nanoporous Thin Films with Tailored Morphology for Biomolecules Adsorption

The adsorption of myoglobin (Mb) onto nanoporous thin films build up using block-copolymers (BCPs) is analyzed. The nanoporous thin films, fabricated by exploiting self-assembly of lamellar BCPs and the concept of sacrificial block, are characterized by a well-defined morphology containing nanochannels of width ≈20 nm delimited by polystyrene (PS) domains, decorated with pendant poly(ethylene oxide) (PEO) chains. The adsorption of Mb onto the nanoporous material is studied by means of UV–visible spectroscopy, quartz crystal microbalance, and neutron reflectometry measurements. In order to determine the role of nanopores, experiments are also conducted by using supports made of nonporous PS thin films and nude glass slides. The results indicate that the BCP-nanoporous material exhibits a remarkably higher adsorption capability than PS and glass. As PEO exhibits a low degree of protein adsorption, this result may be essentially attributed to the presence of the nanopores. The large surface area, the opened pore structure, and the trapping effect of the pores are the main factors determining the increased Mb adsorption capability of the BCP-based support. Yet, the presence of PEO chains decorating the PS walls at porous surface does not prevent Mb biomolecules to establish good interactions with the support.