The effect of the chemical composition and structure of polymer films made from resorbable polyhydroxyalkanoates on blood cell response.

Four PHA types were synthesized in the culture of Cupriavidus eutrophus B-10646 under special conditions, poly(3‑hydroxybutyrate) [P(3HB)] and of copolymers, which contained 3HB monomers and 4‑hydroxybutyrate (4HB), 3‑hydroxyvalerate (3HV), or 3‑hydroxyhexanoate (3HHx). All copolymers had the Mw of about 550-670 kDa, and the homopolymer P(3HB) had a significantly higher Mw - 920 kDa. P(3HB‑co‑4HB) and P(3HB‑co‑3HHx) had the lowest Cx (42 and 49%) while P(3HB‑co‑3HV) and P(3HB) exhibited higher Cx values (76%). Polymer films were prepared from different PHAs. Electron microscopy showed differences in the surface microstructure of the films. Films prepared from the P(3HB) were more hydrophobic and the arithmetic mean surface roughness of 71-75 nm, than the copolymer films, which were hydrophilic (57-60°) and had considerably higher roughness (158-177 nm). Blood parameters (hemoglobin and hemolysis) and response of the cells (erythrocytes, platelets, and monocytes) were studied in experiments with blood directly contacting the surface of the films of PHAs with different compositions. Cultivation of blood cells on polymer films did not cause any adverse effects on adhesion and morphology of all cell types. Results of studying blood cell response suggested that the films made from low-crystallinity copolymers containing 4‑hydroxybutyrate and 3‑hydroxyhexanoate were the best for contact with blood.