Bioinspired superhydrophobic polystyrene surfaces for spatial control of cell attachment/proliferation

Introduction. In this work we propose a biomimetic and simple approach for spatial control of cells, correlating
the surface wettability in the range of superhydrophobic to superhydrophilic with SaOs-2 attachment and
proliferation.

Methods. Superhydrophobic polystyrene (PS) surfaces were produced by a phase separation method and the in vitro performance of SaOs-2, L929 and ATDC5 cell lines assessed in terms of cell morphology and dsDNA content, after 4 hours, 2 and 6 days in incubation. Smooth and rough PS surfaces were chemically modified with UVO irradiation during 6, 9 and 18 minutes to control surface wettability. MTS assay and dsDNA quantification were performed on rough and smooth PS surfaces with controlled wettability with SaOs-2 cells after 4 hours, 2 and 6 days in culture. Superhydrophilic patterns were made on the superhydrophobic PS surfaces using UVO irradiation and hollowed masks. Cellular suspension of SaOs-2 cells was dropped over whole surface or only on the wettable areas and surfaces observed by microscopy after 24 hours in incubation. The surfaces were characterized by contact angle measurements, XPS analysis, optical profilometry and SEM. 

Results. ATDC5 and SaOs-2 cell lines were not able to proliferate on PS superhydrophobic surfaces. After 4
hours in culture, the attachment of SaOs-2 cell line was higher on superhydrophilic PS surfaces whose serum
proteins effects seemed reduced, although the proliferation was higher in surfaces with water contact
angles ranging from 30 to 13°. SaOs-2 cells remained adhered after 24 hours in incubation on the patterned
superhydrophilic regions in both cases (Fig. 1).

Conclusions. This work suggests that the introduction of random micro/nano roughness and further chemical modification by UVO irradiation may be an elegant and easy method to control spatially the attachment/proliferation of cells in distinct materials with possible uses in high throughput, microfluidic or even in 3D systems.