SINGLE PARTICLE TRACKING IN SIMULATED MICROGRAVITY-GROWN BIOFILMS

Bacterial biofilms are a community of bacteria encased in extracellular polymeric substances (EPS) which make eradication more difficult. This advantage makes biofilms a unique clinical threat on Earth. In space, biofilms also pose a threat to astronauts through potential biofilm-associated infections and equipment compromise. To evaluate the role of microgravity in biofilm structure, Streptococcus mutans, an opportunistic oral pathogen, was cultured under simulated microgravity conditions using a custom 2D clinostat. Single particle tracking (SPT) of PEGylated quantum dots (QDs) inside the biofilms post growth was utilized to quantitatively measure potential changes to diffusivity and particle confinement. Particle choice was made after a nanoparticle characterization study of particle size, shape, and zeta potential, and tracking of the QDs in a glycerol-water solution confirmed the QD hydrodynamic diameter. SPT metrics were also used to investigate the role of the growth substrate on biofilms cultured on physiologically and industrially relevant titanium and stainless-steel surfaces.