Many scientific studies have demonstrated the positive influence of both HAp microparticles (µHAp) and nanoparticles (nHAp) on the widely understood properties of PLA and PCL-based composites, particularly in the biological aspect. For example, Madheswaran Subramaniyan et al. prepared PLA-based materials with 0-50 wt% µHAp using extrusion and 3D printing techniques and demonstrated an increase in compressive mechanical properties and hardness in proportion to the added filler. In another publication, the authors demonstrated the potential to improve the thermal stability and surface wettability of extruded PLA composites by adding 5 wt% of fish-derived µHAp . In turn, in our previous work we proved that PLA-based composites with 10-30% HAp microwhiskers can maintain good mechanical properties while also achieving high biocompatibility with osteoblast and fibroblast cell lines. The improvement in mechanical properties with the addition of 10-30 wt% microfiller, together with increased osteoblast activity, has also been reported by Lin PL . The beneficial effect of HAp in the micrometric range has also been observed in PCL. An example of this is the research by Li Y et al. , who showed the improvement in hydrophilicity and surface texture of composites containing 20% and 40% wt% HAp, which was translated into enhanced differentiation of rat bone mesenchymal stem cells. Similarly, the efficacy of incorporating HAp nanoparticles into PLA and PCL has been revealed in numerous studies. Krokos et al. showed a positive effect of adding 10 wt% nHAp on the processability (dynamic flowability) of PLA/HAp microspherical powders used for laser sintering. In turn, Dong Yan's work highlighted the beneficial effect of such nanoparticle additions to PLA microspheres on the efficiency of osteogenic differentiation in rat mesenchymal stem cells. Another noteworthy study by Śmieszek et al. demonstrated improved adhesion and mitochondrial activity in adipose-derived mesenchymal stem cells after incorporation of 10 % nHAp into a PLA-based film. Improved proliferation capacity of MC3T3-E1 osteoblast cells was also observed on scaffolds fabricated by thermally induced phase separation with the addition of 0-75 % nHAp . In addition to the biological properties, some studies indicate improvements in mechanical and thermal stability after doping PLA with HAp nanoplates at levels of 10-30% . A similar role was played by nHAp in numerous studies on PCL/nHAp composites, influencing the improvement of both mechanical and biological properties .