Change in the morphology of hydroxyapatite nanocrystals in the presence of bioaffinitive polymeric species under the application of electrical field

Application of the external electrical field during the precipitation of hydroxyapatite (HAP) nanoparticles in the presence of bioaffinitive polymeric species, individual crystallites as well as their coherent agglomerates increases their anisotropy with the increasing aspect ratio of the crystallites, L-c/L-a or of aggregated particles, d(c)/d(a). The tendency was quite similar when we change the polymeric species between gelatin (GLT) and sodium salt of hyaluronic acid (HYA), although the extent of change is larger for GLT as compared to HYA, presumably due to stronger polymer-HAP interaction in case of HYA. External electrical field often causes severe agglomeration to fairly isotropic particles with substantial loss of the HAP crystallinity. This might be attributed to the strong ionic interaction between and COO- group of HYA, which is not the case with GLT. (c) 2006 Elsevier Ltd. All rights reserved.