Cellular Behaviors on Chemically/Physically Modified SiO 2 Surfaces Chung-Yao Yang 1 , Amarendra Kumar 1 , J. Andrew Yeh 1 Insitute of Engineering and Microsystems National Tsing Hua University Hsinchu, Taiwan d9535803@oz.nthu.edu.tw Yao-Joe Yang Department of Mechanical Engineering National Taiwan University Taipei, Taiwan Abstract—This paper describe an easy-to-handle approach to probe cellular behaviors via using silicon dioxide nanotextures with various functional groups. The silicon dioxide nanotextures were performed through using metal assisted chemical etching and wet oxidation. The pitch of nanotextures can be adjusted by controlling etching durations. The results showed that cells preferred to spread out on nanotextures with longer pitch rather than on nanotextures with shorter pitch. In addition, cells also preferred to adhere on planar surface rather than on nanotextured surface. We believe, this study can help us to get more insights of cell biology and biomedical-relevant researches. Keywords—nanostructures; glass; functional group; cellular behavior; cell morphology I. INTRODUCTION Cell behaviors such as growth, differentiation, migration and death can be influenced by the cell interaction with the surrounding environments. There are various pathways/mechanisms that regulate how a cell senses and replies to the surrounding environments. These include cell- based properties (e.g., integrin-ligand interactions), physical cues (e.g., topographical influences of the surface) and chemical cues (e.g., effects of surface chemistry). The ability to understand and, further, control or modulate cell-substrate interactions (or cell-material interfaces) through transmembrane receptors such as integrin has provided us a more comprehensive understanding of cellular responses associated with the physiologically/pathologically relevant microenvironment wherein single cells attach and spread, coherently linking to cell structural properties and responses. Furthermore, maintaining deregulation and homeostasis which can lead to disease are important under these microenvironmental conditions [1]. There is still a challenge to be solved which is the signaling pathway of focal adhesion based on single protein assembly in the research field of cell adhesion. In particular, the mechanism of cell adhesion and the size/shape of focal adhesion cluster are still mysteries in cell biology. Using micro-/nano-technology combined tools to manipulate these processes in focal adhesion would allow us to regulate cell adhesion in the future. Nano-textured substrates have been shown to significantly influence migration [2], cell adhesion and gene expression [3,4]. The ability of cells to respond to a variety of factors dictates ultimate cell behaviors including proliferation and apoptosis. Numerous researches show that cell-cell interaction in cancer cell lines may be correlated with the regulation of angiogenesis [5,6]. It is crucial to explain how the molecular pathways of angiogenesis resulting in cancer disease, and this knowledge can be used to design suitable drugs for more efficient therapies. Nano-fabricated surfaces with several nanometer scale textures have potentially provided physical-based biocompatible tools to manipulate the arrangement of various cells for studying cell-cell interaction. For investigating cell-substrate/cell-cell interactions of human cancer cells on nanometer scale textures, we provided an easy- to-handle and chemical-based etching to imitate the in vivo environment and functionalize the surfaces with different functional group chemicals with respect to cell-substrate interaction. The most common surface modification scheme for materials is reaction of alkylchlorosilanes with water and/or surface hydroxyl groups in a solution-based process to form a thin alkylsilane film. This process highly depends on reaction temperature, silanol species in solution, and nature of the solvent. Additionally, liquidbased coating process is a time- consuming process and may influence the topography of nano- scale features due to the unsolved molecules in solution. Vapor-phase coating processes via volatile fluorinated alkylsilanes has been demonstrated [7,8], which offers several advantages, compared to liquid-based approaches, which inherently have several major issues including (i) diffusion limited transport of reagents into specific areas, (ii) incomplete wetting of high-aspect ratio structures, (iii) control of dissolved water in non-aqueous solvents, (iv) uncertain reaction in solution, and (v) disposal of solvent waste. Vapor-phase process provides distinct advantages such as (i) efficient transport into high-aspect ratio structures, (ii) no solvent waste, (iii) good control of reagent, and (iv) provide convenient, in situ cleaning prior to deposition. According to these reasons, cell behavior on nanostructures with/without chemicals is unclear due to the liquid phase chemicals may change the topography of nanostructures. Recently, numerous studies have been carried out to fabricate nanostructures on quartz wafer through dry etching approach (i.e., reactive ion etching, inductively coupled plasma, 978-1-4799-4726-3/14/$31.00 © 2014 IEEE 655 Proceedings of the 9th IEEE International Conference on Nano/Micro Engineered and Molecular Systems April 13-16, 2014, Hawaii, USA