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Unformatted text preview: ORIGINAL RESEARCH PAPER A novel method for low load friction testing on living cells Jessica A. Cobb Alison C. Dunn Jiwoon Kwon Malisa Sarntinoranont W. Gregory Sawyer Roger Tran-Son-Tay Received: 11 July 2007 / Revised: 21 November 2007 / Accepted: 21 November 2007 / Published online: 11 December 2007 Springer Science+Business Media B.V. 2007 Abstract A low load tribology technique for study- ing the effects of friction on living cells was developed. Results show a direct relationship between the coef- ficient of friction (COF) and the extent of cell damage. The COF, l , for a glass pin on an intact layer of human corneal epithelial cells is determined to be on the order of l = 0.05 0.02 ( n = 16). The correlations between applied normal load and extent of cell damage, as well as between number of reciprocation cycles and cell damage, are reported. It is also found that cell damage can occur when a loading force as low as 0.5 mN is applied, although the cells appear to be intact. Keywords Cell Friction Human corneal epithelial cell Tribology Introduction Understanding the physical interaction between biomaterials and cells within the body is critical for the development of medical devices. Frictional forces between the two play a crucial role in the safety and life span of devices [e.g. bone cements (Frazier et al. 1997 ) and vascular stents (Ho et al. 2003 )] as well as in patient comfort [e.g. contact lenses (Nairn and Jiang 1995 )]. Therefore, a method is needed for quantifying contact friction between materials and living cells, and assessing the effects of friction not only at the cellular level but also at the sub-cellular level. This is critical because damage due to mechanical loading is not always apparent at the tissue level (Needham et al. 1991 ). Morita et al. ( 2006 ) previously reported a method for friction testing on living, engineered tissue (i.e. cartilage constructs). However, the effects of friction on viability at the cellular level were not evaluated in that study. In addition, the apparatus that was used was limited to minimum applied loads in the Newton range, making it difficult to mimic conditions in vivo. In the present work submerged friction testing was performed on monolayers of live human corneal epithelial (HCE-T) cells, and the effects of friction on cell viability were examined. The method reported here employs applied loads of two orders of magnitude less than those reported by Morita et al. ( 2006 ). J. A. Cobb M. Sarntinoranont R. Tran-Son-Tay ( & ) J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, P.O. Box 116131, Gainesville, FL, USA e-mail: email@example.com A. C. Dunn J. Kwon M. Sarntinoranont W. G. Sawyer R. Tran-Son-Tay Department of Mechanical and Aerospace Engineering, University of Florida, P.O. Box 116250, Gainesville, FL, USA 123 Biotechnol Lett (2008) 30:801806 DOI 10.1007/s10529-007-9623-z Materials and methods Cell culture...
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This note was uploaded on 08/22/2011 for the course EGM 4313 taught by Professor Mei during the Spring '08 term at University of Florida.
- Spring '08