Nanocomposites and nanomaterials

Investigation of the rate of resorption hydroxyapatite-based composites modified by magnetite and chitosan for medical application

Sych O.1, Synytsia A.1, Babutina T.1

1 Department of Functional Materials for Medical Application, Frantsevich Institute for Problems of Materials Science of NAS of Ukraine.
Krzhyzhanovsky Str., 3, Kyiv-03142, Ukraine.
E-mail: synytsia.ann@gmail.com

Biogenic hydroxyapatite (BHA) and composite materials based on it are used in orthopedics and traumatology to replace bone defects of various origins due to its biocompatibility and chemical proximity to the mineral component of natural bone. In addition, materials based on BHA are bioresorption, ie in the process of "dissolution" of the implant is the mineralization of newly formed tissues. One of the most important parameters that in vitro allows to predict the behavior of the material in the body is the study of its behavior in the model physiological environment.
BHA / magnetite / chitosan composite powders based on magnetite obtained by chemical precipitation for 5 minutes and thermolysis in a nitrogen medium with different ratios of components (wt. % BHA / magnetite: 99/1, 95/5, 75/25 and 50/50 at a chitosan content of 0.1%) were used as test materials.
According to the results of the study of the resorption rate of the obtained BHA/ magnetite/chitosan composites under thermostatic conditions in physiological isotonic solution, it was found that not only the content but also the type of magnetite used significantly affects the resorption rate in physiological saline. The increase in the content of magnetite leads to an increase in the resorption of composites, and the use of magnetite obtained by chemical precipitation allows achieving a resorption rate of 2.5-5.3 wt. % / day, which is 3.5-7.5 times higher than "pure" biogenic hydroxyapatite and 1.2-2 times higher than composites based on magnetite obtained by thermolysis in nitrogen.
The obtained results are fully consistent and confirmed by the results of chemical analysis of physiological solutions after contact with composites for 2 days. The presence of such chemical elements as calcium, phosphorus and iron was detected in the filtrates. The presence of calcium and phosphorus is due to the resorption of hydroxyapatite, and iron - magnetite, which are part of the composites. The content of elements in physiological solution is directly related to the ratio of components in the materials of BHA / magnetite / chitosan.