In situ rheology of Staphylococcus epidermidis bacterial biofilms

摘要: We developed a method to grow Staphylococcus epidermidis bacterial biofilms and characterize their rheological properties in situ continuously fed bioreactor incorporated into parallel plate rheometer. The temperature shear rates of growth modeled bloodstream conditions, common site S. infection. measured the linear elastic (G′) viscous moduli (G′′) material using small-amplitude oscillatory rheology yield stress non-linear creep rheology. found that biofilm were 11 ± 3 Pa 1.9 0.5 at frequency 1 Hz (6.283 rad per s) was approximately 20 Pa. response Jeffreys model has characteristic relaxation time 750 seconds viscosity 3000 s. effects on viscoelastic environmental stressors, such as NaCl concentration extremes temperature, also studied. non-monotonic relationship between concentrations, with stiffest human physiological concentrations (135 mM). Temperature dependent showed hysteresis when heated cooled 5 °C 60 °C. Through these experiments, we demonstrated are rheologically complex materials can be characterized by combination low modulus (∼10 Pa), long (∼103 seconds), finite (20 Pa). This suggests should viewed soft solids whose determined part local conditions. introduced here adapted wide range systems applied over broad spectrum conditions because technique minimizes risk irreversible, deformation microbial specimen before analysis.