Molecular interaction of Candida albicans with polymeric materials: Correlation of single cell adhesion forces, gene...

Candida albicans (C. albicans) is a commensal member of the oral microbiota that can form biofilms, contributing to denture stomatitis. Its initial adhesion to abiotic surfaces is a critical step in biofilm formation and is strongly influenced by the material's physicochemical properties. Surface roughness, surface free energy (SFE), and salivary components play key roles in mediating fungal-material interactions. Polymeric materials are components of denture materials, so understanding the interactions with C. albicans is essential to clarify the mechanisms underlying early fungal adhesion. However, the molecular and biophysical mechanisms that govern fungal adhesion to polymer materials are not well characterized. This study examined C. albicans adhesion behavior on polyvinyl chloride (PVC) and polytetrafluoroethylene (PTFE) surfaces with defined roughness levels Ra = 0.2 μm and 0.04 μm) with saliva. Surface properties were characterized using profilometry and contact angle measurements, while adhesion forces and cell-surface interactions were analyzed by single-cell force spectroscopy (SCFS) using atomic force microscopy (AFM) varying contact forces. The expression of the adhesion- and biofilm-associated genes ALS1, HWP1, and EFG1 was quantified by quantitative reverse transcription PCR (qRT-PCR). Rough surfaces resulted in stronger adhesion and more contact points. In contrast, higher SFE was associated with reduced adhesion. Saliva pretreatment modulated these interactions. Gene expression analyses revealed that early adhesion is primarily regulated by polymer-dependent surface signals, while hyphae- and biofilm-specific pathways exhibited minimal activation. In summary, the results demonstrate that the surface properties of polymeric materials significantly influence the early adhesion of C. albicans and its associated molecular responses.