Seminar: We Stress Bacteria Out: Dynamic Responses of Bacteria Under Fluid, Nanoparticle and Antibiotic Stress

Andrew Jones, PhD, Northeastern University

All dates for this event occur in the past.

Scott Laboratory
Scott Laboratory
Room E001
201 W 19th Ave
Columbus, OH 43210
United States

Abstract

Engineered environments concentrate and put bacteria under a lot of stress. In microbial fuel cells (MFCs), corrosion-resistant metals uptake current from metal respiring bacteria such as Geobacter sulfurreducens, producing power from wastewater. While beneficial for engineering applications, corrosion resistant metals induce pH stress on the bacteria. To reduce pH stress, MFCs use forced convection to enhance mass transport of both nutrients and byproducts; however, biofilms’ small pore size limits convection, thus, limiting the effect on pH stress.  Understanding how convection is necessary but not sufficient for biofilm health requires decoupling mass transport from momentum transport (i.e. fluidic shear stress). The speaker uses a rotating disc electrode to decouple mass transport from shear stress. The increased shear stress is shown to reduce biofilm development time, while increasing its metabolic rate. Furthermore, biofilm health is negatively affected by higher metabolic rates over long-term growth due to the biofilm’s memory of the fluid flow conditions during the initial biofilm development phases.

When treating bacterial infections, nanoparticles and antibiotics can induce resistance or tolerance. Nanoparticles are easy to manufacture and act via physical disruption of the bacterial membrane and/or generation of locally high concentrations of reactive-oxygen species, quantified by free energy or enthalpy methods, respectively making them easy to design. However, no quantitative method describes dynamic induction of tolerance or resistance. The speaker applies machine learning to classify survival behavior across nanoparticle types and concentrations. During the presentation, 170 experimental interactions between Escherichia coli, Staphylococcus aureus, Staphylococcus epidermidis, Pseudomonas aeruginosa, Helicobacter pylori and concentrations of liposomal drug delivery systems, amphiphilic peptide and silver and selenium nanoparticles will be compared. Clustering reveals bacteria-nanoparticle separate resistance and tolerance development from stable growth. Furthermore, bacteria-generated nanoparticles do not induce growth dynamics associated with resistance.

These results can be used to improve bacteria viability or susceptibility, particularly in flowing systems like MFCs or blood infections.

 

About the speaker

Andrew Jones, a Future Faculty Fellow at Northeastern, focuses his research on bacterial dynamics, modeling bacterial growth in the presence of nanoparticles and using artificial microporous electrodes to generate chemicals for on-chip sterilization. His past research includes distinguishing the impact of mechanical and nutrient stress on biofilms, quantifying bacterial adhesion on opaque surfaces and modeling advection-diffusion in atomic layer deposition. His work has been recognized with the Center for Biofilm Engineering’s Young Investigator Award, a 2nd Place Poster award at the American Physical Society/Division of Fluid Dynamics Conference and a Sloan Foundation Fellowship. He received his PhD, MS and BS in mechanical engineering and a BS in mathematics from MIT with a focus on transport phenomena.

 

Hosted by Prof. Shaurya Prakash.