Polymer surface micropatterning by plasma and VUV-photochemical modification for controlled cell culture

Surface chemical micropatterns have been created by both low-pressure ‘‘cold’’ plasma, and by vacuum ultraviolet (VUV) photochemical modification of biaxially oriented polypropylene (BOPP). Oxygen, nitrogen and ammonia plasma, and ammonia- VUV treatments have been performed, including through metal masks with micrometer-sized openings. Surface analysis by X-ray photoelectron spectroscopy (XPS) has been used to characterise the modified surfaces. Imaging time-of-flight secondary ion mass spectrometry (ToF-SIMS) of partially masked regions has demonstrated the ability to produce micrometer scale chemical patterns of oxygen and nitrogen-containing functionalities, for example, hydroxyl and amine groups, contrasted with untreated hydrocarbon regions. Nitrogen and ammonia plasma patterned surfaces, and ammonia-VUV patterned surfaces have been used to control the immobilisation and growth of foetal bovine cerebellar neurons and growth plate chondrocytes cells in culture.