Rapid Mix Preparation of Bioinspired Nanoscale Hydroxyapatite for Biomedical Applications

The overall goal of this procedure is to rapidly, reliably, and conveniently prepare a high quality Bioinspired Hydroxyapatite Nanoparticle. This method is used to prepare Nanoscale Hydroxyapatite, a material of great scientific and commercial interest, to researchers developing innovative medical devices, and related healthcare technologies. Particularly for clinical applications.

The main advantage of this technique, is that it's much more convenient than traditional titration reactions. And it retains versatility and reproducibility of previously published methods. To begin the procedure, add 3.705 grams of calcium hydroxide to 500 milliliters of deionized water.

hydroxide to 500 milliliters of deionized water. Then combine 3.459 grams of 85%by weight aqueous phosphoric acid, with 250 milliliters of deionized water. Pour the phosphorous solution into the calcium hydroxide solution while stirring at a rate of approximately 100 milliliters per second.

When preparing the reagents, it's important to measure the calcium hydroxide and phosphoric acid as precisely as possible for optimum results. This is to obtain the starting calcium to phosphorous molar ratio as close to 1.67 as possible. Cover the mixture with laboratory film.

Stir the mixture for one hour at 400 rpm and then allow the nHA mixture to settle over night. To obtain approximately five grams of nanoscale hydroxyapatite. Next pour off the supernatant.

Add 500 milliliters of deionized water. Stir the nHA mixture for one minute at 400 rpm. And allow the mixture to settle for two hours.

Repeat this washing process at two hour intervals, three times in total. Allow the washed nHA suspension to settle over night. Then pour off the supernatant, and dry the suspension at 60 to 80 degrees celsius.

Once the nHA material has dried, grind the nHA to a fine powder with an agate mortar and pestle. Transfer 2.5 grams of the ground nHA powder to an alumina crucible. Retain the remaining powder for later characterization.

Sinter the nHA powder at 1000 degrees celsius for two hours with a ramp rate of 10 degrees celsius per minute. After sintering allow the nHA to cool in the furnace. Store the prepared nHA powders in a vacuum desiccator for characterization and further use.

Characterize the sintered and unsintered powders with x-ray diffraction, TEM, x-ray fluorescence, and FTIR. Using this method, nanoscale hydroxyapatite was prepared and characterized. Transmission electron microscopy showed the particle dimensions to be around 50 nanometers by 30 nanometers.

With an aspect ratio of 1.7. X-ray diffraction showed a pure hydroxyapatite phase with broad peaks, indicating a small crystallite size or amorphous nature. After sintering, the presence of Beta-Tricalcium Phosphate was detected, indicating partial thermal decomposition.

The sintered powder peaks were all sharper than those of the unsintered sample, suggesting an increase in crystallite size during sintering. The hydroxyapatite phase formation was confirmed by FTIR ATR. Water and carbonate bands were also observed in the unsintered powder.

After sintering the phosphate and hydroxyl bands appear sharper in the absorbance plot, indicating greater crystallinity. Quantitative chemical analysis was performed with x-ray fluorescence. The nHA product was highly pure, showing only trace amounts of other elements.

The calcium to phosphorous molar ratio was determined to be 1.63, which was slightly sub stoichiometric. This combined with the indication of thermal decomposition from the x-ray diffraction data, suggests that this method produces a calcium deficient hydroxyapatite species. After this process had been developed and optimized, it was used in a wide range of projects involving the manufacture of innovative biomaterials.

After watching this video, you should have a good understanding of how to apply our method, for the rapid production of bioinspired nanoscale hydroxyapatite in your laboratory. This new method marks a significant improvement, in terms of both speed and relative simplicity for the manufacture of nanoscale hydroxyapatite. We predict that this work will be adopted by industry for the manufacture of medical grade, bioinspired, nanoscale hydroxyapatite for a range of applications in medicine, dentistry and consumer health.