A 2D surface morphology–composition gradient panel for protein-binding assays

We designed a two-dimensional (2D) morphology–composition gradient panel, which has a gradient in surface morphology at constant chemical composition along its length and a gradient in surface chemical composition without change of surface morphology in the orthogonal direction. The panels, which exhibit a 2D gradient in surface wettability, were fabricated by thermolysis of parylene-C followed by oxygen-plasma treatment for various times. As a demonstration study, binding of three different biotinylated serum proteins (B-IgG, B-A, and B-TF) to the 2D panel was investigated. The 2D gradient panels will facilitate development of optimized binding surfaces for various biotechnological applications.