Influence of Fiber Diameter and Surface Structure of Polycaprolactone Nanofibrous Materials on Yeast Retention and Biofilm Formation

Abstract

Understanding how microorganisms interact with nanofibrous materials (NMs) is essential for designing functional surfaces, yet morphology–yeast interactions remain far less studied than bacterial systems. Here, we investigated how fiber diameter and secondary surface structuring of poly-ε-caprolactone (PCL) NMs affect yeast retention, adhesion, biofilm development, and cell transfer. Five PCL NMs were prepared from two PCL molecular weights (PCL45, PCL80) as smooth fibers and as structured fibers generated by two distinct post-processing routes: polymer-spray-induced texturing (PCL45_80, PCL80_80) and enzymatic surface restructuring (PCL80_E). Interactions with model yeasts (Candida albicans ATCC 10231 and ATCC 90028; Saccharomyces cerevisiae ATCC 9763 and CCM 8381) were assessed by retention, biofilm biomass and metabolic activity during static growth (2 h, 24 h, 72 h), and SEM imaging; cell transfer from colonized agar to NMs was measured using an adapted agar-mesh assay. All tested PCL NMs exhibited high retention (84.7–100%), regardless of fiber diameter or secondary structures. Material-dependent differences were most pronounced during early adhesion, whereas biofilm formed on all NMs and its biomass was strongly strain-specific. Overall, NMs with larger fiber diameter (PCL80 series) supported denser yeast colonization than PCL45, while the secondary structures used here did not confer antifungal activity nor enhance biofilm formation. For cell transfer, PCL45_80 exhibited the highest attachment potential, yet ∼50 % of cells remained on the donor surface. Collectively, these results show that PCL nanofiber morphology modulates yeast–surface interactions primarily by tuning early attachment and colonization capacity.