ИСТИНА

Liver cancer is one of the most dangerous oncologic diseases. Radioembolization is the most effective method of liver cancer treatment, involving the introduction of beads containing radionuclides (β-emitters) into the tumor artery, resulting in tumor local destruction [1]. Alginate hydrogels cross-linked with divalent and trivalent metal ions are promising materials for radionuclide carrier creation due to their radionuclide sorption properties, biocompatibility and biodegradability [2]. This work is devoted to the synthesis and modification of beads based on alginate hydrogels with the aim of creating radionuclide carriers for radioembolization (Figure 1). In this work, alginate beads cross-linked with various cations, including Ca2+, Y3+, Fe3+, and modified with calcium phosphate mineral inclusions were synthesized. The modification was carried out in two ways: 1) enzymatic synthesis of calcium phosphate particles in hydrogel medium; 2) immobilization of pre-synthesized hydroxyapatite in alginate beads. The obtained millimeter-sized beads were characterized by optical, electron microscopy and EDX methods. The structure features of the obtained beads were investigated by IR and Raman spectroscopy. The yttrium and phosphorus sorption kinetics and capacity of alginate beads with different composition were studied using spectrophotometry and radiotracers (90Y and 32P) in water solution. The sorption kinetics is described by an equation of pseudo-second order. The sorption values approach the limiting values in 4-5 hours. Mineralization has been demonstrated to enhance the sorption capacity of the material, with values reaching 3.1 mg/g for yttrium and 3.8 mg/g for phosphorus (phosphate ions). The beads display low desorption of 90Y and 32P in saline solution (0.7% desorbtion in 48 h) and moderate desorption in serum (2.2% desorbtion in 48 h). The kinetics of the 89Y - 90Y isotopic exchange between solution and alginate beads containing 89Y was studied. A high rate of this process was demonstrated. Consequently, the findings indicate the potential for the synthesis of radionuclide β-emitters carriers based on alginate beads and incorporation of radionuclides in these beads through the processes of isotope exchange and sorption for medical applications.