Assessing cytotoxicity : a comparative analysis of biodegradable and conventional 3D-printing materials post-steam sterilization for surgical guides

Abstract

Introduction. Ecological concerns and the depletion of petroleum resources have driven the exploration of biodegradable 3D-printing materials derived from bio-renewable sources, such as polylactic acid (PLA) and polyhydroxyalkanoates (PHA). This study aimed to compare the potential cytotoxic effects of a biodegradable PLA/PHA blend filament, a conventional photopolymer (MED610), and a combination of MED610 with a support material (SUP705) before and after steam sterilization in vitro, with a focus on their application in the production of surgical guides. Materials and Methods. PLA/PHA, MED610, and SUP705 (both in their pure and steam-sterilized forms; n = 6 per group) were assessed for their cytotoxic effects on human fibroblasts using the neutral red uptake assay. Positive controls included zinc diethyldithiocarbamate and zinc dibutyldithiocarbamate, while high-density polyethylene served as a negative control. A stock solution of the extraction medium was used as the vehicle control (VC). Results. Significant differences in cell viability were observed between pure PLA/PHA (1.2 ± 0.24) and MED610 (0.94 ± 0.08) (p = 0.005). However, both materials exhibited non-cytotoxicity, with cell viability exceeding 70% compared to VCs. SUP705 (0.58 ± 0.42) demonstrated significantly reduced cell viability compared to PLA/PHA (p = 0.001) and MED610 (p = 0.007). After steam sterilization, no significant difference in cell viability was noted between MED610 (1.0 ± 0.08) and PLA/PHA (1.2 ± 0.25) (p = 0.111). While both materials remained non-cytotoxic after sterilization, SUP705 (0.60 ± 0.45) exhibited cytotoxic effects compared to MED610 (p = 0.006) and PLA/PHA (p < 0.001). Steam sterilization did not induce significant cytotoxic effects in the investigated materials (p = 0.123). Conclusion. Pure and steam-sterilized PLA/PHA and MED610 were not cytotoxic, supporting their potential use in the production of surgical guides. However, the observed cytotoxicity of SUP705 suggests caution in scenarios requiring sterile conditions, as the removal of support material from complex printed parts may be challenging. The consideration of PLA/PHA is recommended in such settings to ensure biocompatibility.