title: Stretching-induced nanostructures on shape memory polyurethane films and their regulation to osteoblasts morphology.
abstract: Programming such as stretching, compression and bending is indispensible to endow polyurethanes with shape memory effects. Despite extensive investigations on the contributions of programming processes to the shape memory effects of polyurethane, less attention has been paid to the nanostructures of shape memory polyurethanes surface during the programming process. Here we found that stretching could induce the reassembly of hard domains and thereby change the nanostructures on the film surfaces with dependence on the stretching ratios (0%, 50%, 100%, and 200%). In as-cast polyurethane films, hard segments sequentially assembled into nano-scale hard domains, round or fibrillar islands, and fibrillar apophyses. Upon stretching, the islands packed along the stretching axis to form reoriented fibrillar apophyses along the stretching direction. Stretching only changed the chemical patterns on polyurethane films without significantly altering surface roughness, with the primary composition of fibrillar apophyses being hydrophilic hard domains. Further analysis of osteoblasts morphology revealed that the focal adhesion formation and osteoblasts orientation were in accordance with the chemical patterns of the underlying stretched films, which corroborates the vital roles of stretching-induced nanostructures in regulating osteoblasts morphology. These novel findings suggest that programming might hold great potential for patterning polyurethane surfaces so as to direct cellular behavior. In addition, this work lays groundwork for guiding the programming of shape memory polyurethanes to produce appropriate nanostructures for predetermined medical applications.
authors.affiliation: Key Laboratory of Biorheological Science and Technology, Ministry of Education, and Research Center of Bioinspired Materials Science and Engineering, College of Bioengineering, Chongqing University, Chongqing 400030, China.
authors.forename: Juan
authors.initials: J
authors.lastname: Xing
authors.affiliation: Key Laboratory of Biorheological Science and Technology, Ministry of Education, and Research Center of Bioinspired Materials Science and Engineering, College of Bioengineering, Chongqing University, Chongqing 400030, China; Center for Human Tissue and Organs Degeneration, Institute Biomedical and Biotechnology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China.
authors.forename: Yufei
authors.initials: Y
authors.lastname: Ma
authors.affiliation: Key Laboratory of Biorheological Science and Technology, Ministry of Education, and Research Center of Bioinspired Materials Science and Engineering, College of Bioengineering, Chongqing University, Chongqing 400030, China.
authors.forename: Manping
authors.initials: M
authors.lastname: Lin
authors.affiliation: Key Laboratory of Biorheological Science and Technology, Ministry of Education, and Research Center of Bioinspired Materials Science and Engineering, College of Bioengineering, Chongqing University, Chongqing 400030, China.
authors.forename: Yuanliang
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Center for Human Tissue and Organs Degeneration, Institute Biomedical and Biotechnology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China.
authors.forename: Haobo
authors.initials: H
authors.lastname: Pan
authors.affiliation: Center for Human Tissue and Organs Degeneration, Institute Biomedical and Biotechnology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China. Electronic address: cs.ruan@siat.ac.cn.
authors.forename: Changshun
authors.initials: C
authors.lastname: Ruan
authors.affiliation: Key Laboratory of Biorheological Science and Technology, Ministry of Education, and Research Center of Bioinspired Materials Science and Engineering, College of Bioengineering, Chongqing University, Chongqing 400030, China. Electronic address: yfluo@cqu.edu.cn.
authors.forename: Yanfeng
authors.initials: Y
authors.lastname: Luo
mesh_terms: D001672:Biocompatible Materials / Q000737:chemistry*; D002478:Cells, Cultured; D005353:Fibronectins / Q000737:chemistry*; D006801:Humans; D057927:Hydrophobic and Hydrophilic Interactions; D008422:Materials Testing; D018625:Microscopy, Atomic Force; D049329:Nanostructures / Q000737:chemistry*; D010006:Osteoblasts / Q000166:cytology*; D011091:Polyesters / Q000737:chemistry; D011140:Polyurethanes / Q000737:chemistry*; D053838:Scattering, Small Angle; D014961:X-Ray Diffraction
chemical_list: D001672:Biocompatible Materials; D005353:Fibronectins; D011091:Polyesters; D011140:Polyurethanes; C033616:poly(lactide)
keywords: Chemical patterns; Nanostructures; Osteoblasts; Polyurethane film; Stretching