Plasma Processing of Polymeric Materials to Tune Antibacterial Properties for Environmental & Biomedical Applications

Research seminar abstract

Polymeric constructs are widely used in medical and environmental settings, such as scaffolds for wound healing and drug release, membranes for dialysis and water treatment, and tubing for blood transport.1 Polymers are often chosen for their desirable bulk properties, such as porosity, biodegradability, mechanical strength, and architecture; however, most are hydrophobic and suffer from bacterial attachment and proliferation.1 These limitations make such polymers unsuitable for interfacing with aqueous environments where microbes exist, such as in water treatment and biomedical applications. To combat bacterial proliferation, biocidal agents can be blended into the polymer to eradicate microbes, yet material hydrophobicity makes it difficult to ensure this action occurs at the material-biological interface. Plasma processing is well known to tailor surface properties and maintain bulk properties critical to the material performance, but I aim to further explore the utility of several plasma processes to create constructs with improved antibacterial properties.

This work will first demonstrate how H2O (v) plasma surface modification improves wettability and performance of ultrafiltration membranes used for water purification. Surface modification results are comprehensively assessed with various surface analysis techniques (e.g., contact angle goniometry, X-ray photoelectron spectroscopy, and scanning electron microscopy), combined with performance testing to evaluate membrane flux and recovery after protein fouling.2 The first approach to improving antibacterial properties translates H2O (v) plasma treatment to drug-releasing materials and establishes the capability to tune biocide release kinetics. Short (2-5 min) plasma treatments significantly enhance wettability and oxygen content of both Ag-loaded scaffolds and NO-releasing Tygon. Compared to the untreated polymer, treated NO-releasing Tygon had a delayed, but equally dramatic 8-log reduction in population of gram-negative E. coli and gram-positive S. aureus, without reducing total drug release.3 A second tactic to control bacterial growth utilizes plasma-enhanced chemical vapor deposition to deposit a coating from a novel essential oil-derived antibacterial precursor. Bacterial attachment and biofilm formation assays reveal drastically reduced bacterial growth on coated substrates. By correlating gas phase species (observed via optical emission spectroscopy) with surface characterization results, the antibacterial properties of the films can be further fine-tuned. These related strategies collectively illustrate plasma processing is advantageous towards both improving material compatibility in aqueous environments and achieving control over biocidal capabilities.

 

(1)           Bazaka, K.; Jacob, M.V.; Chrzanowski, W.; Ostrikov, K. RSC Adv. 2015, 5, 48739.

(2)           Pegalajar-Jurado, A.; Mann, M. N.; Maynard, M. R.; Fisher, E. R. Plasma Process. Polym. 2015, 598-610.

(3)           Mann, M.N.;Neufeld, B.H.; Hawker, M.J.; Pegalajar-Jurado, A.; Paricio, L.N.; Reynolds, M.M.; Fisher, E.R. Biointerphases 2016, 11, 031005.

Division(s): Materials

Speaker: Michelle Mann

Speaker Institution: Colorado State University

Event Date: 05-05-2017

Event Time: 4:00 PM

Event Location: Chemistry A101

Mixer Time: 3:45 PM

Mixer Location: Chemistry B101E

Host: E. Fisher