guidelines. L929 cells (passages 9-11) were cultured in growth media consisting of DMEM, 10% FBS, 2 mM L-glutamine, 100 U/ml penicillin, and 100 µg/ml streptomycin in T25 flasks. For the experiments, sub-confluent T25 flask cultures of L929 cells were trypsinized, and 1 × 10 4 cells were seeded per well in a 96-well plate. Simultaneously, 100 µm-thick films of PBF-DLF copolyester and a reference material (polycaprolactone PCL CAPA® 6430) were cut into three 6 cm 2 samples, which were then sterilized under UV-C light for 15 minutes on each side. Subsequently, the material samples (n=3) were sectioned into smaller pieces and placed in a 24-well plate, with 1 ml of medium added to each well. The plates were incubated for 24 hours at 37 °C in a 5% CO2 environment to allow the cells to adhere and spread. After this incubation, the media were aspirated, and 100 µl of growth media containing extracts from the tested materials were added to the wells (with 6 technical replicates performed for each material). A sham control was prepared by adding 100 µl of pure growth media. The plate was incubated for an additional 24 hours, after which cell viability was evaluated using an inverted light microscope (Delta Optical IB-100) and a resazurin viability assay . The assay was conducted with a fluorescent plate reader (Biotek Synergy HTX) at an excitation wavelength of 540 nm and an emission wavelength of 590 nm. During the resazurin viability assay, complete growth media were added to an empty well without cells, serving as the blank. The results obtained were expressed as the percentage of normalized cell viability (CV%), calculated using Equation (2) :