ARTICLE Effects of Vibration on Differentiation of Cultured PC12 Cells Yukiko Ito, 1 Tsuyoshi Kimura, 1 Kwangwoo Nam, 1 Ayako Katoh, 2,3 Toru Masuzawa, 3 Akio Kishida 1 1 Institute of Biomaterials and Bioengineering, Tokyo Medical and Dental University, Tokyo, 101-0062, Japan; telephone: þ81-3-5280-8028; fax: þ81-5280-8028; e-mail: kishida.fm@tmd.ac.jp 2 Japan Association for the Advancement of Medical Equipment, Japan 3 Faculty of Engineering, Ibaraki University, Ibaraki, Japan Received 1 June 2010; revision received 12 September 2010; accepted 14 September 2010 Published online 11 October 2010 in Wiley Online Library (wileyonlinelibrary.com). DOI 10.1002/bit.22961 ABSTRACT: Different types of physiological-mechanical stress, such as shear stress in vascular endothelial cells or hydrostatic pressure in chondrocytes are well known as regulators of cell function. In this study, the effects of vibration, a type of non-physiological mechanical stimula- tion, on differentiation of rat pheochromocytoma (PC12) cells are reported. A nano-vibration system was designed to produce nanometer-scale vibration. The frequency and amplitude of the nano-vibrations were monitored by a capacitance displacement sensor connected to an oscillo- scope. When PC12 cells exposed to nerve growth factor were subjected to vibration at 10 kHz, differentiation and elonga- tion of their neurites were promoted earlier in the culture. Vibration promoted differentiation of PC12 cells. This approach could therefore also be promising for determining of the effects of the physical environment on cell differentiation. Biotechnol. Bioeng. 2011;108: 592–599. ß 2010 Wiley Periodicals, Inc. KEYWORDS: nano-vibration; PC12 cell; morphological analysis; differentiation Introduction Cell engineering has become an important field and has enabled the manufacture of a wide variety of products, such as antibodies, proteins, cytokines, and cells themselves. The key factors in the advancement of cell engineering are knowledge of and the ability to control cell function. Many materials and technologies have been proposed to control the function of cells (Bao and Suresh, 2003; Vogel and Sheetz, 2006). Well-known methodologies include the use of chemical substances such as drugs, the use of biological materials such as cytokines, and the use of physical stimuli such as stretching. Among these, physical stimulation has attracted the interest of researchers because the progress in manufacturing technologies enables a wide variety of ideas to be realized. Many approaches, such as an oscillating electric magnetic field (Adey, 1993; Panagopoulos et al., 2002), hydrostatic pressuring (Furukawa et al., 2008; Mizuno et al., 2002), and gravity culturing (Boonstra, 1999; Moes et al., 2007) have been shown to successfully influence cellular functions. Physical stimulation has been shown to be a key stimulant affecting the functions of many types of cells (Albinsson et al., 2004; Albinsson and Hellstrand, 2007; Butler et al., 2009; Conway et al., 2009; Diamond et al., 1989; Furukawa et al., 2008; Mizuno et al., 2002; Obi et al., 2009; Yamamoto et al., 2003). Obi et al. (2009) and Yamamoto et al. (2003) reported that fluid shear stress from 0.1 to 2.5 dyn/cm 2 markedly augmented the increase in the kinase insert domain-containing receptor, fms-like tyrosine kinase-1, and vascular endothelial-cadherin expression in EPCs. Albinsson et al. (2004) and Albinsson and Hellstrand (2007) showed that stretching the vascular wall promoted actin polymer- ization and induced the synthesis of differentiation marker proteins such as SM22a. Furthermore, it has been reported that hydrostatic fluid pressure (HFP) of 0–3.5 MPa stimulated chondrogenesis in vivo during normal walking (Furukawa et al., 2008; Mizuno et al., 2002). The above studies showed that physical stimulation similar to physiological conditions could control and enhance cell function in vitro. There are also magnetic technologies that activate signaling pathways and control cell function, such as magnetic tweezers (Sniadecki, 2010), magnetic bead force application (Fass and Odde, 2003; Wang and Ingber, 1994), and magnetic twisting cytometry (Alenghat et al., 2009; Wang and Stamenovic ´, 2000). Cellular signal transduction Correspondence to: Akio Kishida Contract grant sponsor: Ministry of Health, Labor and Welfare (MHLW) Contract grant sponsor: Ministry of Education, Culture, Sports, Science and Technol- ogy (MEXT) Contract grant sponsor: Ministry of Economy, Trade and Industry (METI) Contract grant sponsor: Japan Society for Artificial Organs (JSAO) 592 Biotechnology and Bioengineering, Vol. 108, No. 3, March, 2011 ß 2010 Wiley Periodicals, Inc.