| AVS 63rd International Symposium & Exhibition | |
| Biomaterial Interfaces | Tuesday Sessions |
| Session BI+PB-TuP |
| Session: | Biomaterial Interfaces Poster Session (preceded by Oral Flash Presentations) |
| Presenter: | Daniel Barlow, US Naval Research Laboratory |
| Authors: | D.E. Barlow, US Naval Research Laboratory LJ. Nadeau, Air Force Research Laboratory C.S. Hung, Air Force Research Laboratory J.C. Biffinger, US Naval Research Laboratory A.L. Crouch, Air Force Research Laboratory J.N. Russell, US Naval Research Laboratory W.J. Crookes-Goodson, Air Force Research Laboratory |
| Correspondent: | Click to Email |
Two hydrolases secreted by Pseudomonas protegens Pf-5 bacteria, PueA and PueB, have been demonstrated to be active towards polyester - polyurethane (PU) hydrolysis. In this work, the impact of these enzymes towards PU degradation was directly compared at biofilm / PU interfaces through deletion of PueA and PueB genes. Unsaturated biofilm assays were used where biofilm growth took place on solid, hydrated PU discs in air. PU degradation was analyzed using confocal Raman microscopy of intact samples. Additionally, cross-sectional analysis of microtomed sections was done using FTIR microscopy and combined atomic force microscopy – infrared spectroscopy (AFM-IR). Results showed varying degrees of biofilm related permeation and polymer degradation within the ~300 um thick discs. Degradation took place through a pitting process involving preferential loss of the ester component. Wild type and PueB knockout mutants showed the highest levels of hydrolysis, measured by loss of carbonyl intensity in vibrational spectra, while the PueA and double knockout mutants showed lower hydrolysis levels. The apparent higher level of PueA activity is consistent with higher enzymatic activity for the hydrophobic lipase substrate, p-nitrophenyl palmitate. Relationships between biofilm morphology and PU degradation were also observed for the wild type and mutant biofilms.