Plenary speakers

  1. Managing Director

Interfacial Fluid Mechanics and Rheology to the Rescue: Applications in Human Health

Gerald G. Fuller
Fletcher Jones II Professor
Department of Chemical Engineering, Stanford University
Shriram Center, 443 Via Ortega, Room 086, Stanford, CA 94305-4125
Abstract :
Biofilms are multicellular communities consisting of microorganisms enmeshed in an extracellular matrix of biopolymers. The matrix provides the community structure and cohesiveness and allows it to adhere to a variety of interfaces. These factors allow biofilms to persist in a variety of settings, ranging from large-scale industrial equipment to medical implants in the human host. In fact, many infections are now appreciated to be biofilm-related and are difficult to treat by traditional means such as antibiotics.
To combat unwanted biofilms, a current strategy is to take a biophysical approach and interfere with the biofilm structure by disrupting the extracellular matrix. This strategy could revoke the survival advantages provided to the microorganisms by existing in the biofilm community. It also avoids the life-or-death pressure placed on microorganisms by traditional antibiotic treatment that gives rise to drug resistant mutations. However, to achieve this goal of targeting the extracellular matrix, we require an improved understanding of the underlying mechanical properties of the biofilm structure.
In this lecture, I describe the use of modified rheological methods to quantify mechanical interactions relevant at all stages of the biofilm lifecycle, including: initial microbial adhesion to interfaces, maturation of the biofilm structure, and microbial dispersal. A Live Cell Monolayer Rheometer (LCMR) was used to study adhesion of uropathogenic Escherichia coli to bladder epithelial cells, the initial step in bladder infection. In a separate study, interfacial shear rheology was used to study the maturation of biofilms formed at the air-liquid interface by Vibrio cholerae, the causative agent of cholera. It was discovered that out of several known extracellular matrix components in the V. cholerae biofilm, a specific matrix protein called Bap1 contributed significantly to maintenance of biofilm elasticity, biofilm hydrophobicity, and development of a mature biofilm structure.