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Difficult-to-treat bone damage resulting from metabolic bone diseases, mechanical in-
juries, or tumor resection requires support in the form of biomaterials. The aim of this research
was to optimize the concentration of individual components of polymer–ceramic nanocomposite
granules (nanofilled polymer composites) for application in orthopedics and maxillofacial surgery
to fill small bone defects and stimulate the regeneration process. Two types of granules were
made using nanohydroxyapatite (nanoHA) and chitosan-based matrix (agarose/chitosan or curd-
lan/chitosan), which served as binder for ceramic nanopowder. Different concentrations of the
components (nanoHA and curdlan), foaming agent (sodium bicarbonate—NaHCO3), and chitosan
solvent (acetic acid—CH3COOH) were tested during the production process. Agarose and chitosan
concentrations were fixed to be 5% w/v and 2% w/v, respectively, based on our previous research.
Subsequently, the produced granules were subjected to cytotoxicity testing (indirect and direct con-
tact methods), microhardness testing (Young’s modulus evaluation), and microstructure analysis
(porosity, specific surface area, and surface roughness) in order to identify the biomaterial with the
most favorable properties. The results demonstrated only slight differences among the resultant
granules with respect to their microstructural, mechanical, and biological properties. All variants
of the biomaterials were non-toxic to a mouse preosteoblast cell line (MC3T3-E1), supported cell
growth on their surface, had high porosity (46–51%), and showed relatively high specific surface area
(25–33 m2/g) and Young’s modulus values (2–10 GPa). Apart from biomaterials containing 8% w/v
curdlan, all samples were predominantly characterized by mesoporosity. Nevertheless, materials
with the greatest biomedical potential were obtained using 5% w/v agarose, 2% w/v chitosan, and
50% or 70% w/v nanoHA when the chitosan solvent/foaming agent ratio was equal to 2:2. In the case
of the granules containing curdlan/chitosan matrix, the most optimal composition was as follows:
2% w/v chitosan, 4% w/v curdlan, and 30% w/v nanoHA. The obtained test results indicate that both
manufactured types of granules are promising implantable biomaterials for filling small bone defects
that can be used in maxillofacial surgery.
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