Authors: Camille Bryner, Alyson Camacho, Bowen J Houser
Mentors: William G Pitt
Insitution: Brigham Young University
In an attempt to combat a growing number of nosocomial infections related to medical devices, many studies have investigated the effect of polydopamine (pDA) coated surfaces on biofilm formation and found them to have antibacterial and anti-adhesive properties. However, we discovered that pDA coated magnetic nanoparticles (MNPs) display strong attractive interactions with many, but not all, species of bacteria. Fe3O4 MNPs were prepared using sodium acetate, ethylene glycol, and iron (III) chloride hexahydrate solutions and characterized by a variety of methods. XRD data confirmed a magnetite pattern characteristic of Fe3O4, then TEM characterization of MNP samples showed successful pDA coating onto iron oxide particles. Bacterial capture efficiencies (CE) by pDA-MNPs for 8 strains of bacteria were measured by optical turbidity and plate counts. We have found that CE is a function of exposure time to and concentration of MNPS; thus some experiments were done with constant exposure time and variable MNP concentration and others were done at variable exposure times and constant MNP concentrations. Additionally, these pDA-MNPs exhibit extremely efficient adhesion to some bacteria such as Staphylococcus epidermidis (S. epidermidis) while being ineffective at capturing some strains of Esherichia coli (E. coli). We propose that such capture ability of pDA-coated MNPs can be employed for detection and identification of bacteria in hospitals and for food science quality control.