Papers by Author: K.E. Tanner

Abstract: A fixed microelectrode device for cell stimulation has been designed and fabricated using micro-electromechanical systems (MEMS) technology. Dielectrophoretic forces obtained from non-uniform electric fields were used for manipulating and positioning osteoblasts. The experiments show that the osteoblasts experience positive dielectrophoresis (p-DEP) when suspended in iso-osmotic culture medium and exposed to AC fields at 5 MHz frequency. This work will help to investigate the mechanisms underlying Wolff’s law of bone growth dynamics at the cellular level. The methods used can also be developed to control osteoblast metabolism and ultimately enhance bone repair processes.

Abstract: Injectable bone substitutes (IBS) based on calcium phosphate (CaP) and/or calcium sulphate (CaS) are used as fillers in bone defects to stimulate bone integration and allow mechanical loading. Two types of IBS, IBS-1 is CaP+20%CaS and IBS-2 is CaS+40% hydroxyapatite, were investigated. The materials were injected into holes in the femur and tibia in rabbits. After 10 weeks the femora were subjected to indentation testing and tibiae were prepared for histology evaluation. IBS-1 lead to an higher indentation load compared to control, that is no material inserted, while IBS-2 showed no significant difference between material and control. Histology showed that with IBS-1, the bone penetrated into and integrated with the material in the defect. With IBS-2, new bone grew into the outer 0.5-1.0 mm. The materials could be used for different indications, such as to support fracture healing or in contained cavities.