Fabrication of selective anti-biofouling surface for micro/nanopatterning of proteins

Abstract

This paper reports a simple method for creating a functionalized surface for the efficient micro/nanopatterning of proteins by micromolding in capillaries (MIMIC) of poly(ethylene glycol)-poly(lactide) diblock copolymer (PEG-PLA) and self-assembled polyelectrolyte multilayers (PEL). The fabricated surface consisted of two distinct regions: a PEL region to promote protein immobilization and a PEG-PLA background as a biological barrier to prevent the nonspecific binding of proteins. When the ability of anti-biofouling of PEG-PLA was compared with the most widely used blocking agents, such as bovine serum albumin (BSA) and skim milk, the PEG-PLA prevents the nonspecific adsorption of several proteins. The properties of a functionalized surface were characterized by the water contact angle and atomic force microscopy (AFM). Topological analysis clearly indicated that the MIMIC method provides a reliable surface regardless of the micro- and nanopattern size. Two different functionalities of the fabricated surface produce uniform protein patterns from the micro- to nanoscale with a high signal to noise ratio. The proposed method allows for flexibility in forming shapes, such as lines, squares, circles, triangles and stars, and can control the pattern size from 400 nm to 90 μm. Finally, the antigen-antibody assay showed good linearity over the range of 10 ng/mL to 25 μg/mL, indicating its feasibility for a quantitative measurement of the concentration of target proteins in a sample.