title: Evaluation of a new CPC-to-gauge bonding technique with the use of in vitro fluid flow.
abstract: Strain gauging enables the measurement of bone deformation during physical activity, leading to a better understanding of the physiological effects of loading on bone growth and remodeling. Development of a technology that will withstand long-term in vivo exposure and bond securely to bone is imperative for accurate, consistent measurement collection. Polysulfone is currently used to attach calcium-phosphate ceramic (CPC) particles, which promote bone-to-gauge bonding, to polyimide-backed strain gauges. This study evaluated the use of an implant-grade epoxy as an alternative CPC-polyimide adhesive. Polyimide-epoxy-CPC interfaces were loaded to failure and shear strengths calculated. In vitro studies providing a constant flow of medium over test specimens were designed, and long-term in vitro fluid exposure studies of the epoxy's shear strength were conducted. Average shear strength of polysulfone-polyimide interfaces were reported to be 7 MPa. The average shear strength of the epoxy-polyimide interface before long-term in vitro exposure was 17 MPa, which is stronger than the shear strength of the bone-CPC interface. The strength of the epoxy-polyimide interface decreased to 6.8 MPa after 24 weeks in vitro and 3 MPa after 24 weeks in vivo.
authors.affiliation: Orthopaedic Research Laboratory, Department of Orthopaedic Surgery, University of Arizona, Tucson, Arizona, USA. markf@u.arizona.edu
authors.forename: Mark M
authors.initials: MM
authors.lastname: Fernandez
authors.forename: John A
authors.initials: JA
authors.lastname: Szivek
authors.forename: David S
authors.initials: DS
authors.lastname: Margolis
mesh_terms: D000818:Animals; D001672:Biocompatible Materials / Q000378:metabolism*; D001843:Bone Cements / Q000737:chemistry; D001842:Bone and Bones / Q000378:metabolism*; D002130:Calcium Phosphates / Q000737:chemistry / Q000378:metabolism*; D002516:Ceramics / Q000737:chemistry / Q000378:metabolism*; D004852:Epoxy Compounds / Q000737:chemistry / Q000378:metabolism*; D008297:Male; D008422:Materials Testing; D051381:Rats; D017207:Rats, Sprague-Dawley; D013314:Stress, Mechanical; D013718:Tensile Strength
chemical_list: D001672:Biocompatible Materials; D001843:Bone Cements; D002130:Calcium Phosphates; D004852:Epoxy Compounds