Engineering biofilm growth regimes in FDM-printed plastics through material selection

Biofilm formation on 3D-printed surfaces presents either a challenge to mitigate or an opportunity to exploit. While medical and industrial applications require suppressing microbial colonization, biofilm-based biotechnologies rely on rapid, stable establishment. Here, we demonstrate that FDM-printed plastics define tunable regimes of early biofilm formation through material selection. Ten polymers and composites, including PLA+, ABS, PC+, and glass-fiber reinforced variants, were evaluated against six microbial strains. SEM (Scanning Electron Microscopy) and machine-learning-assisted image analysis revealed distinct colonization patterns, ranging from minimal attachment to matrix-rich coverage. PA, PC+, and ABS/PA-GF8 were highly biofilm-prone, while HIPS, PP, and TPU showed significantly lower susceptibility. Surface topography and glass-fiber reinforcement were identified as key drivers of these differences. These results establish a framework for engineering biofilm growth on FDM plastics, enabling precise material selection to either suppress or promote colonization. These findings provide design guidance for additive manufacturing in biofouling-sensitive and biofilm-enabled applications.