Date of Award

5-2013

Degree Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Polymers and High Performance Materials

Committee Chair

Marek W. Urban

Committee Chair Department

Polymers and High Performance Materials

Committee Member 2

William L. Jarrett

Committee Member 2 Department

Polymers and High Performance Materials

Committee Member 3

Sarah E. Morgan

Committee Member 3 Department

Polymers and High Performance Materials

Committee Member 4

Sergei I. Nazarenko

Committee Member 4 Department

Polymers and High Performance Materials

Committee Member 5

Mohamed O. Elasri

Committee Member 5 Department

Biological Sciences

Abstract

This dissertation focuses on the design, synthesis, and development of antimicrobial and anticoagulant surfaces of polyethylene (PE), polypropylene (PP), and poly(tetrafluoroethylene) (PTFE) polymers. Aliphatic polymeric surfaces of PE and PP polymers functionalized using click chemistry reactions by the attachment of –COOH groups via microwave plasma reactions followed by functionalization with alkyne moieties. Azide containing ampicillin (AMP) was synthesized and subsequently clicked into the alkyne prepared PE and PP surfaces. Compared to non-functionalized PP and PE surfaces, the AMP clicked surfaces exhibited substantially enhanced antimicrobial activity against Staphylococcus aureus bacteria. To expand the biocompatibility of polymeric surface anticoagulant attributes, PE and PTFE surfaces were functionalized with pH-responsive poly(2-vinyl pyridine) (P2VP) and poly(acrylic acid) (PAA) polyelectrolyte tethers terminated with NH2 and COOH groups. The goal of these studies was to develop switchable stimuli-responsive polymeric surfaces that interact with biological environments and display simultaneous antimicrobial and anticoagulant properties. Antimicrobial AMP was covalently attached to –COOH terminal ends of protected PAA, while anticoagulant heparin (HEP) was attached to terminal –NH2 groups of P2VP. When pH < 2.3, the P2VP segments are protonated and extend, but for pH > 5.5, they collapse while the PAA segments extend. Such surfaces, when exposed to Staphylococcus aureus, inhibit bacterial growth due to the presence of AMP, as well as are effective anticoagulants due to the presence of covalently attached HEP. Comparison of these “dynamic” pH responsive surfaces with “static” surfaces terminated with AMP entities show significant enhancement of longevity and surface activity against microbial film formation. The last portion of this dissertation focuses on the covalent attachment of living T1 and Φ11 bacteriophages (phages) on PE and PTFE surface. This was accomplished by carbodiimide coupling between –COOH groups on PE and PTFE surfaces and –NH2 moieties present on T1 and Φ11 phages. These studies show that covalently attached T1 and Φ11 phages retain their antimicrobial activity manifested by the effective destruction of both Gram negative Escherichia coli (Φ11) phages and Gram positive Staphylococcus aureus bacteria (T1).

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