Light activated anti-infective biomaterials for healthcare

Abstract

Medical devices play a vital role in the therapeutic care of patients during illness but are often limited by microbial colonisation. Microbial adhesion to a medical device’s surface is the first step in the infection process and is crucial for the pathogenicity of device-associated infections. This research work investigated two common problems associated with medical device use and two alternative approaches that could be used to reduce microbial colonisation and prevent resistant microorganisms.

The first experimental chapter investigated if pathogens could be displaced during urinary catheterisation as a possible cause of catheter-associated urinary tract infections. Intermittent catheters were inserted into an in vitro urethral model to assess whether pathogens located around the urethral meatus could be displaced up the urethral canal towards the bladder.

The second experimental chapter investigated the effect different types of catheter surfaces had on catheter insertion and withdrawal forces. During catheterisation, lubricity needs to be maintained at the catheter’s surface to prevent friction from occurring between the catheter’s surface and urethral mucosa. The texture analyser and an in vitro urethral model were used to characterise and rank the lubricity of a range of intermittent catheters.

The third experimental chapter investigated the properties of two EGDPEA copolymers and assessed their potential for resisting bacterial attachment to their surface. Both copolymers’ surface properties were characterised using a range of spectroscopic and physical methods and their microbial properties were assessed by trying to grow biofilms of bacteria which typically cause infection.

The fourth experimental chapter investigated antimicrobial photodynamic therapy as an approach to eliminate pathogens and biofilm formation using specific wavelengths of light and exogenous photosensitisers to generate toxic levels of reactive oxygen molecules. The bactericidal effects of two photosensitisers were assessed by loading onto two EGDPEA copolymers and testing against S. aureus and E. coli.

Thesis is embargoed until 31 December 2028.

Date of Award	Dec 2023
Original language	English
Awarding Institution	Queen's University Belfast
Sponsors	Engineering & Physical Sciences Research Council
Supervisor	Colin McCoy (Supervisor) & Louise Carson (Supervisor)