Biophysicist, Soft Matter Enthusiast, Associate Professor at Georgia Tech. Views are my own.
Atlanta, GA
Joined December 2016
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We tested this against a bunch of microbes: prokaryotes and eukaryotes, gram positive and gram negative bacteria, anaerobic and aerobic species, different cell sizes and shapes, and differences in extracellular matrix production. It worked in every case we tested!
ALT Data showing that interface model works for nice different species / strains of microbes
But here, it allows us to construct a simple model of vertical growth that features a linear increase in growth rate up to a characteristic size, followed by a linear decrease in growth rate.
ALT Data demonstrating that interface model works best
Physics, that’s how! Diffusion limits how much nutrients can diffuse in. As a result, exponential growth can only occur up to a characteristic size. This diffusion limit is of course well known.
ALT Nutrient concentration at different distances from interface
Back to biofilms. We watched how biofilms grew over time.
These observations allowed us to compute how the growth rate depends on biofilm height
ALT Biofilm height vs time and change in height versus height.
For example, to see cells on the surface of a tomato, you:
1. Put tomato down.
2. Scan tomato. That’s it!
ALT Picture of tomato on interferometry and image of cells from interferometer scan
We overcome these barriers using white-light interferometry, which enables us to continuously measure the topography of developing biofilms with nanometer resolution out-of-plane.
ALT Biofilm profiles at different times
OK, really this work is studying how biofilms grow vertically. Here I’ll explain what the problems were, what we found, and how we can measure topography with nanometer resolution. (And in this case “we” really means @pabravoc who did incredible work here!)
ALT Biofilm topography at different times
Just in time for the start of the school year we have a new print studying how biofilms grow up:
biorxiv.org/content/10.1101/…
ALT Topographies of different microbes
