Small-scale mechanical testing: Applications to bone biomechanics and mechanobiology Marnie M Saunders, Assistant Professor Center for Biomedical Engineering, University of Kentucky, 205 Wenner-Gren Laboratory, Lexington, KY 40506-0070 marnie.saunders@uky.edu ABSTRACT Mechanical testing of biologic tissues requires flexible testing machines to accommodate a variety of testing needs. This paper will illustrate how a cost-effective testing platform was developed to accommodate a wide range of biomechanical testing applications including bone bending and torsion testing, soft tissue tensile testing and bone cell stimulation via fluid shear and substrate deformation. The goal is to demonstrate to the reader that unique issues arise when testing biologic tissues such as controlling for environment and maintaining specimen viability, but with proper care relatively reproducible and accurate testing results can be obtained with a simple, multi-purpose platform. The bone research field is a multidisciplinary field in which researchers from the life sciences and engineering work to understand the development, structure, function and pathologies of bone. It is hoped that knowledge gained from this basic science understanding will result in improved implants, engineered replacement tissues and therapies/strategies to counteract metabolic bone diseases, to name a few applications. As the field continues to evolve the role of the traditional biomechanical engineer is evolving and few biomechanical engineers find themselves in a pure mechanical testing environment. Rather they are collaborating with biologists to quantify mechanical properties of bone in genetically altered animals, they are collaborating with material scientists to characterize novel biomaterials, and they are collaborating with bioengineers to develop devices and approaches to study bone at the cellular level. As such, biomechanical engineers need testing platforms and skill sets that can accommodate this range of interests. And, given the novelty of many of the research projects, off- the-shelf, commercial fixtures are not always available or appropriate. Our lab has approached this need by developing a multi-purpose, small-scale testing platform. In this paper we discuss the basics of our system, demonstrate its applications and acknowledge its limitations. The goal is to illustrate to the reader that mechanical testing of biologic tissues is a unique field and the testing results are only as good as the devices and techniques used to obtain them. Mechanical testing machines have been a useful tool in the bone field for several decades. As such, there are several excellent papers and books available to the interested reader that detail appropriate mechanical testing procedures for bone [1-5]. The focus of this paper is on the development of a platform to cost-effectively deal with varied and sporadic biomechanical testing needs without sacrificing data accuracy. Furthermore, the goal is to show that this system can duplicate systems developed by other researchers to stimulate bone and bone cells, providing a powerful, multi-purpose testing frame. To begin the design and fabrication of our small-scale loading machine we looked to the types of commercial testing platforms available and considered the design against our current and likely future needs. Commercially, testing machines are uniaxial and biaxial with the latter comprising both torsional and rotational capabilities. Given that the vast majority of our testing needs are uniaxial we opted for the single axis design and determined that torsion capabilities using the single axis could be added at a later date. We set out initially to accommodate the most common types of testing needs in our lab: bend testing of bones, compression testing of hard tissues, tension testing of soft tissues, in vivo exercise loading, and fluid shear and substrate deformation of bone cells. While we have previously detailed the development of the loading platform [6], we will summarize briefly the major components and considerations of the machine. Generally single axis machines are on a fixed frame. While we will illustrate later in this article the advantages of using a movable frame, we found that an inexpensive way to create the two main components of the platform, the linear, vertical Proceedings of the SEM Annual Conference June 7-10, 2010 Indianapolis, Indiana USA ©2010 Society for Experimental Mechanics Inc. 345 for Experimental Mechanics Series 15, DOI 10.1007/978-1-4419-9794-4_48, © The Society for Experimental Mechanics, Inc. 2011 T. Proulx (ed.), Time Dependent Constitutive Behavior and Fracture/Failure Processes, Volume 3, Conference Proceedings of the Society