Control of Human Osteoblast adhesion on polymers after ion beam irradiation

INTRODUCTION: when a biomaterial is inserted in the body, the biological responses are associated with their surface properties. Surface treatments are developed to create some mimetic polymer or biomaterials with high performances, preserving the bulk properties and creating some specific interaction between the designed surfaces and the bio molecules or the cells. Some applications require the control of the cell behaviour: protein adsorption, cell proliferation, cell differentiation, cell mobility, spreading etc. The field of polymers application is vast and the surface treatment must be adapted: biosensors, tissue engineering, tissue regeneration, neural probes, drug delivery, bio- actuators etc. METHODS: The surface treatment of organic materials by ion beam offers some advantages (1-3) : the depth of treatment is well controlled, the treatment could be local or total without mask (at the scale cell), surface modifications (scission, cross-linking, grafting, topography etc.) depend on the parameters of irradiation, and the treatment process is clean and realised in high vacuum. Polymers samples (PTFE, PMMA, PEEK, PET, HDPE, Parylene) are irradiated with a 900 keV Helium beam produced by a Van de Graaf Accelerator. The Polymers are cut out by a water jet at 13 mm diameter to be easily put in the cellular culture box. Three lines of irradiation are realized on each sample (line: 500 μm width, 6 mm length). Cell cultures are done with an Osteoblast hFOB 1.19 lines from ATCC. After the treatment, samples are sterilized. Then they are immerged in a PBS medium culture heated at 37 °C. 10 000 Osteoblast cells are introduced with a pipetman and let incubated during 96 hours at 37° C with 5% of CO2. The cells are fixed with formol and after rinsing the cells are coloured with a blue Toluidine solution, then they are cleaned and let dried. Observations were performed with an Olympus® microscope.