Micropatterned hydrogel surfaces for controlled cell adhesion

Spatially resolved radiation from a scanning electron microscope can be used to create micro- and nanoscopic hydrogels from poly(ethylene glycol) [PEG] with an approach similar to the electron-beam patterning of polymeric photoresists. We show that the patterned features generated by electron-beam cross-linking swell when exposed to water. The extent of swelling depends on the incident electron dose. Because of the significance of PEG in biomaterials applications, we examined the adsorption of fibronectin and laminin onto the PEG microhydrogels using immunofluorescence optical microscopy. Undetectable levels of protein are observed for low dose patterns. The amount of adsorbed protein increases with the dose and reaches a maximum at the highest doses where swelling is not observed. As part of ongoing research on patterning surfaces to control neurite growth in the context of the inflammatory environment of a spinal cord injury, we are interested in how these gel surfaces interact with macrophages. We show that the number of adhered macrophages can be also controlled by the irradiation conditions. By spatially patterning combinations of low and high swelling gels, we show that macrophage adhesion can be confined to specific locations on the surface.