title: Change in creep behavior of plexiform bone with phosphate ion treatment.
abstract: The effect of phosphate ions on the mechanical properties of plexiform bone in tension was investigated with an in-vitro model. Bone samples were treated with saline and phosphate ion solutions for three days at 25 degrees C and 37 degrees C and tested in tension. The mechanical properties of the bone samples treated with phosphate were not different than controls (saline treated). Electro kinetic measurements on plexiform bone particles treated with phosphate ions at 37 degrees C showed that phosphate ions alter electro kinetic potentials of bone particles by interacting with bone mineral as compare to saline treated particles near physiological pH. Because of the limited diffusion properties of intact plexiform bone tissue, the tension experiments indicate that, the effect of phosphate ions on the bone mineral-matrix interface is negligible after three days treatment. On the other hand, electro kinetic measurements demonstrated that in a short period of treatment time, phosphate ions diffuse through organic matrix barrier and interact with bone mineral when plexiform bone is in the particle form. As a final experiments bone samples were tested at 37 degrees C in three point bending configuration for three days in saline and phosphate buffer solution. The maximum tension stress generated in bending samples was about 75 percent of the tension yield stress of the samples. The creep experiments showed that the bending rigidity of bone samples tested in phosphate solution reduced in time hence the creep deformation increased compare to control samples tested in saline. This observation is attributed to the acceleration of phosphate ion diffusion into the bending samples due to micro cracks accumulation in bone tissue during the creep experiments which facilitated the phosphate ion interaction with bone mineral.
authors.affiliation: The University of Medicine and Dentistry of New Jersey-SOM, Biomechanics Laboratory, Tr.#4, 675 Hoes Lane, Piscataway, NJ 08854, USA.
authors.forename: R L
authors.initials: RL
authors.lastname: Regimbal
authors.forename: C Alex
authors.initials: CA
authors.lastname: DePaula
authors.forename: N
authors.initials: N
authors.lastname: Guzelsu
mesh_terms: D000818:Animals; D002417:Cattle; D002592:Cetomacrogol / Q000494:pharmacology; D004548:Elasticity; D004586:Electrophoresis / Q000379:methods; D005269:Femur / Q000187:drug effects* / Q000502:physiology*; D019791:Guanidine / Q000494:pharmacology*; D006801:Humans; D066298:In Vitro Techniques; D010710:Phosphates / Q000494:pharmacology*; D012016:Reference Values; D012680:Sensitivity and Specificity; D013314:Stress, Mechanical; D013718:Tensile Strength; D014783:Viscosity
chemical_list: D010710:Phosphates; D002592:Cetomacrogol; D019791:Guanidine; C018279:sodium phosphate