PBS And PTFE Modified With PIII And Researched As Biomaterials

Poly(butylenes succinate)(PBS), which is a biodegradable aliphatic polyester developed in recent 20 years, provides excellent processability, superior mechanical properties, adjustable biodegradability and good biological safety. However, the insufficient biocompatibility limits its application in tissue engineering. In this study, plasma immersion ion implantation(PIII) has been utilized to conduct PBS surface modification with various gases(O₂, H₂O, N₂ and NH₃). The resultant changes of surface physical and chemical properties are systematically investigated. Furthermore, the seeded osteoblasts behaviors and the in vitro bioactivity are evaluated and discussed. The conventional PIII technique has been improved by adding filter. Consequentially, long pulse-high frequency PIII can be achieved on polymer surface. Medical polytetrafluoroethylene(PTFE) substrates have been oxygen-treated in 3 modes: (1) long pulse-high frequency PIII; (2) conventional short pulse-low frequency PIII and (3) plasma immersion. The influences of different treatments on PTFE surface properties were studied. The main results of the work are summarized as below:(1) PBS substrates were modified with various gas(O₂, H₂O, N₂ and NH₃) PIII. The results indicate that all the gas PIII induced corresponded chemical groups on PBS surfaces. Both the surface hydrophilicity and the surface roughness were evidently improved after gas PIII.(2) The osteoblast compatibility of PBS substrates before and after various gas PIII were systematically investigated. The fluorescence stained osteoblasts observations and the cell viability assay results jointly indicate that all gas PIII can significantly improve the osteoblasts adhesion and proliferation on PBS samples. And the adhered osteoblasts also spread better on the treated samples.(3) The proteins and gene expressions of seeded osteoblasts on PBS substrates before and after various gas PIII were investigated. When the incubation time 12 days adopted, both N₂ PIII and NH₃ PIII can promote the seeded osteoblasts differentiation and maturation, but O₂ PIII and H₂O PIII did not take similar effects. All the samples were soaked in a simulated body fluid(SBF) for 14 and 28 days to investigate the surface bioactivity, the results show that gas PIII can change PBS surface from bioinert to bioactive.(4) Medical PTFE samples were treated with 3 methods as long pulse-high frequency O₂ PIII, short pulse-low frequency O₂ PIII, and O₂ plasma immersion. The results show that, only the long pulse-high frequency O₂ PIII treatment can yield a super-hydrophobic surface with the water contact angle above 150°. All the 3 treatments can significantly improve the osteoblasts adhesion and proliferation on PTFE samples. However, long pulse-high frequency O₂ PIII is the most beneficial method to promote seeded osteoblasts differentiation and maturation. The inhibitory rate of long pulse-high frequency O₂ PIII PTFE to S. aureus is also higher than the other 2 treated samples.