Surface Modification by Allylamine Plasma Polymerization Promotes Osteogenic Differentiation of Human Adipose-Derived Stem Cells Xujie Liu, † Qingling Feng,* ,†,‡ Akash Bachhuka, § and Krasimir Vasilev §,∥ † State Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, Beijing 100084, China ‡ Key Laboratory of Advanced Materials of Ministry of Education of China, School of Materials Science and Engineering, Tsinghua University, Beijing 100084, China § Mawson Institute, University of South Australia, Mawson Lakes 5095, Australia ∥ School of Advanced Manufacturing, University of South Australia, Mawson Lakes 5095, Australia * S Supporting Information ABSTRACT: Tuning the material properties in order to control the cellular behavior is an important issue in tissue engineering. It is now well-established that the surface chemistry can affect cell adhesion, proliferation, and differentiation. In this study, plasma polymerization, which is an appealing method for surface modification, was employed to generate surfaces with different chemical compositions. Allylamine (AAm), acrylic acid (AAc), 1,7-octadiene (OD), and ethanol (ET) were used as precursors for plasma polymerization in order to generate thin films rich in amine (−NH 2 ), carboxyl (−COOH), methyl (−CH 3 ), and hydroxyl (−OH) functional groups, respectively. The surface chemistry was characterized by X-ray photoelectron spectroscopy (XPS), the wettability was determined by measuring the water contact angles (WCA) and the surface topography was imaged by atomic force microscopy (AFM). The effects of surface chemical compositions on the behavior of human adipose-derive stem cells (hASCs) were evaluated in vitro: Cell Count Kit-8 (CCK-8) analysis for cell proliferation, F-actin staining for cell morphology, alkaline phosphatase (ALP) activity analysis, and Alizarin Red S staining for osteogenic differentiation. The results show that AAm-based plasma-polymerized coatings can promote the attachment, spreading, and, in turn, proliferation of hASCs, as well as promote the osteogenic differentiation of hASCs, suggesting that plasma polymerization is an appealing method for the surface modification of scaffolds used in bone tissue engineering. KEYWORDS: plasma polymerization, surface modification, osteogenic differentiation, human adipose-derived stem cell, bone tissue engineering 1. INTRODUCTION Bone tissue engineering has emerged as a promising route for the treatment of healing bone defects. 1 Tissue engineering aims to fabricate biologically inspired scaffolds capable of integrating with native tissue and/or stimulate the body’s innate repair mechanisms to regenerate damaged tissue and restore function. 2 Within the tissue-engineering paradigm, cells, scaffolds, and biological molecules are generally referred to the key components. 3 Thus, it is vital to understand the relationship between the cells and the materials used in bone tissue engineering. It has been demonstrated that the topography, 4,5 chemical compositions, 6 mechanical properties, 7 and architecture 8 of scaffolds are able to interact and influence cell behavior, including the attachment, proliferation, migration, and differentiation. In bone tissue engineering, the supplement of autologous osteocytes is limited. 9 Consequently, increasing attention has focused upon the use of stem cells, such as bone marrow Received: April 9, 2014 Accepted: June 3, 2014 Research Article www.acsami.org © XXXX American Chemical Society A dx.doi.org/10.1021/am502170s | ACS Appl. Mater. Interfaces XXXX, XXX, XXX−XXX