2020 Virtual AIChE Annual Meeting
(543g) Diffusive Transport within Cellulose Biofilms
Bacterial biofilms are complex biological networks containing diverse forms of polymeric structures that drastically affect local rheology and transport within the film. Diffusion through biofilms is a function of the key length scales of the matrix components and their mesostructures, a critical determinant of the impact of therapeutic nanoparticles or competitive microorganisms on the film. A number of studies have examined diffusion of nanoparticles within molecular networks of polysaccharides, but here we examine diffusion through larger cellulose microfiber structures produced by Acetobacter xylinum. Knowledge of transport variations within bacterial cellulose networks could be used to guide design of therapeutic particles, understand evolutionary pressures guiding biofilm growth, and enhance use of nanocellulose networks in applications like wound dressing and bandages. We use optical microscopy and single particle tracking of multiple tracer particle sizes to explore the effect of biofilm structure on diffusive mobility and transport. The tracer particle sizes span the characteristic length scales of the heterogeneous interconnected cellulose fiber network, allowing us to map the regimes of nanoparticle mobility and confinement. We use mean squared displacement, particle displacement distribution, and non-Gaussian parameter to characterize tracer particle dynamics within the bacterial biofilms and characterize network heterogeneity.