2024 AIChE Annual Meeting

(562e) Kinetics of Capture of Gram-Positive Bacteria By Polydopamine-Coated Magnetic Nanoparticles

Authors

Pitt, W., Brigham Young University
Camacho, A. N., Brigham Young University
Bryner, C. A., Brigham Young University
Okonkwo, T. P., Brigham Young University
Harrison, R. G., Brigham Young University
Chesnel, K., Brigham Young University
In this study, we explored the rapid capture of pathogenic bacteria using polydopamine (pDA)-coated magnetic nanoclusters (MNCs). While pDA is typically reported as anti-bacterial and anti-biofilm-forming in other publications, we observed strong attractive interactions between pDA-MNCs and several Gram-positive bacteria species—including the pathogenic bacteria Streptococcus mutans, usually seen in dental caries, and the opportunistic pathogens Staphylococcus epidermis and Staphylococcus aureus.

The MNCs were synthesized using a solvothermal process consistent with previous publications, producing clusters of nanoparticles that are about 120 nm in diameter as measured by scanning electron microscopy. A pDA coating was synthesized upon the surface of the MNCs and estimated to be 5 nm thick with transmission electron microscopy.

The kinetics of bacterial capture were measured by mixing pDA-coated MNCs with a bacterial suspension, collecting the MNCs with a strong magnet after various incubation times, and then measuring how many bacteria remained in suspension (not collected by MNCs) after each incubation time. When fit to a mathematical model, the kinetic data for S. mutans suggests there is first-order capture with respect to both bacteria and MNC concentration at short times. Further research is being conducted on the kinetics of S. epidermidis and S. aureus.

These kinetic details can be used to scale processes for bacterial capture in applications in biomedical diagnostics, and in food and water quality assessment.