Highly-ordered micro-patterned surfaces on different polymers such as poly(methyl metacrylate) (PMMA), poly(caprolactone) (PCL), and poly(styrene-co-maleic anhydride) (PSMA) were successfully fabricated by utilizing the single-step phase separation method which is a facile and less humidity-sensitive method for preparing micro-patterned polymer thin films. The effects of temperature, addition of surfactants, and the modulated concentrations of solvents and nonsolvent on the distribution and surface morphology of surface patterns were examined. It was found that the addition of surfactants facilitated the formation of highly ordered concave patterns, while the diameter of the concaves was crucially controlled by the amount of water added as nonsolvent into the polymer solutions. Various organic solvents such as tetrahydrofuran, acetone, acetonitrile, methyl acetate, methyl acetate, chloroform, and dichloromethane were selectively combined with the purpose of obtaining an ideal solvent for the creation of regularly ordered micro-concave patterns on different polymer surfaces. It was observed that the regularity of the patterns was mainly dictated by the solubility parameters (χ) and the density of solvents.
The created micro-patterned PMMA and PSMA surfaces with varied diameter of concave structures were further employed to investigate the L-929 fibroblast cell behaviors on the microstructure environments. Surface characterizations performed by atomic force microscopy and water contact angle measurements demonstrated that the roughness and hydrophobicity of the micro-concave patterned PMMA films increased as the concave diameter increased. Furthermore, several biomolecules (collagen, bovine serum albumin (BSA), and dopamine) were incorporated by immobilization onto or blending into the micro-patterned PMMA in order to study the interactions between biomolecules and mammalian cells. The cell density evaluated by lactate dehydrogenase (LDH) assay and imaged by confocal microscopy revealed that the adhesion and proliferation of L-929 fibroblasts were amplified by the size of the concaves. Furthermore, we found that the adhesion and morphology of cells were significantly affected by the participation of collagen and dopamine, while the addition of BSA suppressed the cell adhesion and growth. However, at large diameter of concave patterns (20 – 44 μm), the promotion of cell adhesion was governed mainly by the topography, regardless the addition of biomolecules.
Beside the coating and single-step addition methods to include the biofunctionalities, plasma technique was also employed to proceed surface modifications. Firstly, N2/H2 plasma was applied integrate amine groups on the concave-patterned PSMA surfaces where a significant increase of L-929 cell growth and proliferation was observed in comparison with the pristine PSMA. Moreover, CF4 plasma was used to treat concave and convex patterned polydimethylsiloxane (PDMS). The results indicated a clear increase of cell adhesion and proliferation on both the patterns with different diameter between 7 – 50 μm on the CF4 plasma treated samples when compared to the untreated ones.

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