Dual surface activation of thermoplastic polyurethane (TPU) guided membranes

Thermoplastic polyurethane (TPU), which consisting of alternant hard- and soft segment is a kind of segmented block copolymer. Amazing elasticity, transparency, and strength at break have expanded the application of TPU in automotive, buildings, coatings, sealants, medicine, and rubber industries. Further, TPUs lack active group, they have high crystallinity, low surface energy, and chemical inertness. Therefore, its properties needed to restore. Recently, plasma or alkali treatment have been suggested to modify the surface properties of nanostructures. Especially, alkali treatment is also versatile one, and creates changes in dimensions, and fine structure without change the surface functional groups. The aim of this study was to evaluate the influence of surface treatment method on newly identified TPU membranes containing of phosphatidylcholine (PC) and polyethylene glycol (PEG). Raw TPU surface was modified by alkali treatment with different percentages of NaOH: 1M and 3 M without heating for a constant soaking time of 30 min. Surface morphology, roughness and wettability properties of treated TPU membranes were investigated. The experimental results showed that the all treated TPU membranes showed surface feature morphology with increasing roughness, i.e. Sa (areal average roughness) values of the TPU-PEG or TPU-PC after the submersion in 1 M solution of NaOH became about 2.51x102±15.6 and 2.79x102±17.3 nm while that of TPU was 6.24x101±6.9 nm. Furthermore, while the contact angle values of TPU-PEG after alkalization reduced from 40.6±0.5° to 21±0.2° and patterned TPU-PC showed significantly superior cell attachment to the MC3T3-E1 cells than the pristine TPU. The study’s findings indicate NaOH-treated composite TPU membranes could be a possible guided agent, which supported the bone induction, and differentiation.