Effect of hydroxyapatite sintering temperature on intracellular ionic concentrations of monocytes: A TEM-cryo-X-ray microanalysis study

Hydroxyapatite used as bone replacement can lead to particle release in the implantation site. These particles interact with monocytes, which are the first immune cells to colonize the implant and an inflammatory site. Thanks to cryo-X-ray microanalysis, we can observe cells in a state close to the physiological one and we have access to diffusible ions. We paid particular attention to the potassium-to-sodium ratio, which is one of the best viabi lity criteria. We used this method to study the interaction between three h ydroxyapatite particles treated at three different temperatures (not treate d, treated at 600 degreesC and 1180 degreesC), and monocytes, In the cultur e condition, the hydroxyapatite treated at 1180 degreesC underwent the leas t dissolution. We demonstrate that monocytes were altered by the three hydr oxyapatite particles. The hydroxyapatite particules treated at 600 degreesC were found to be more toxic. (C) 2001 John Wiley & Sons, Inc.