17 2025 2025-03-03 10.48309/jmpcr.2025.484155.1469 The purpose of this work was to develop a synthesis technique and study the physico-chemical properties of copper carbonate nanoparticles (CC-NPs) stabilized with biopolymers to assess their biocompatibility and toxicity. For the synthesis of CC-NPs, Cu(CH3COO)2 and CuCl2 were used as Cu precursors, while K₂CO₃, (NH₄)₂CO₃ and (NH₄)₂CO₃ were used as precipitators. The following biopolymers were used as stabilizing agents: chitosan, methylcellulose, hydroxyethyl cellulose and hyaluronic acid. The experimental data showed that Cu(CH3COO)2 is the optimal precursor and (NH4)2CO3 is the optimal precipitator for the production of CC-NPs. The optimal sample consists of spherical aggregates with a diameter of 0.6 to 1.0 µm formed by nanoparticles with a diameter of 30 to 80 nm. This sample has a phase composition of Cu2(OH)2CO3. All considered biopolymers were appropriate for stabilization of CC-NPs, but hyaluronic acid was selected as the optimal stabilizing agent. Interestingly, 10 mg of CC-NPs+HA powder caused 100% mortality of chicken embryos. The structural and surface properties of CC-NPs+HA powder allowed it to be absorbed on the surface of CAM while preserving the implantation site throughout the experiment. It is worth noting that the implantation of the CC-NPs+HA sample was accompanied by a clearly identified degradation of small and large vessels. Thus, the results of CAM assay indicate pronounced toxic changes in CAM under the action of CC-NPs+HA. Surprisingly, despite the fact that Cu is an essential trace element, the developed CC-NPs+HA complex is characterized by low biocompatibility and high toxicity. © 2025 by SPC (Sami Publishing Company). https://repo.bashgmu.ru/publication/4853 https://repo.bashgmu.ru/files/5029