Influence of serum and polystyrene plate type on stability of Candida albicans biofilms.

Adhesion is a crucial initial step in microbial biofilm formation. Firm attachment to a target surface subsequently ensures successful colonization and survival despite turbulent conditions. In the laboratory, polystyrene plates are commonly used in biofilm experiments and the 'washing/rinse steps' before staining are critical for assaying biofilm viability. However, these rinse steps risk the removal (partially or entirely) of the formed biofilm, resulting in inconsistent results. The aim of the present study was to optimize conditions for firmer biofilms, less prone to disruption and thus significantly reducing well-to-well variability. Candida albicans SC5314 was used in five different polystyrene 96-well plates from four different manufacturers. Irrespective of how gently we performed the rinse, biofilms came off certain polystyrene plates more easily compared to others. Importantly, preconditioning the polystyrene surfaces with foetal bovine serum (FBS) had a negative impact on firm biofilm attachment. Costar® plates provided the most suitable surface for firm biofilm attachment, both in the presence and absence of FBS. Substratum properties even among seemingly identical synthetic materials may influence biofilm attachment and its subsequent sturdiness, affecting experimental results.