title: Understanding Biofilms
title: Plasma Polymer Coatings to Prevent Biofilm Formation and Understanding the Chemical Pathway to Their Formation by Spectroscopy
titleType: Subtitle
Creators: name: Crisp, Amy
Publisher: name: Lancaster University
Year: 2024

description: Biofilm is the name of microbial communities, where microorganisms
 irreversibly adhere to each other and a surface, whilst encompassed by a
 complex extracellular matrix. Biofilms are ubiquitous throughout the
 world, but in the healthcare system they pose a significant threat,
 particularly in the infection risk of blood contacting materials. Once an
 infection progresses to
 
 a biofilm, there are limited effective treatment options to completely
 eradicate them. A substantial issue in clinical management is identifying
 when the microbes in an infection have switched from a planktonic to a
 biofilm phenotype. Despite efforts to develop new treatments, due to the
 adaptable nature of microorganisms and the mounting antimicrobial
 resistance crisis,
 
 prevention is the best option to combat biofilm infection mortality. A
 proposed solution is to treat all blood contacting materials with an
 anti-biofouling coating. In this research project, both biofilm
 diagnostics and coatings to prevent biofilm growth have been investigated.
 
 
 Vibrational spectroscopy can reveal the precise chemical composition of
 natural
 
 materials, whilst remaining non-destructive and requiring minimal sample
 preparation. FTIR has been successfully applied in this work to identify
 chemical markers of intact bacterial (S. epidermidis) and fungal (C.
 albicans) biofilms, and for the first time FTIR has chemically defined the
 timeframe for irreversible attachment to a substrate. This foundational
 study provides a baseline to support FTIR for implementation in clinical
 diagnosis to identify infection maturity, informing treatment options.
 
 
 Plasma polymerisation has been utilised to produce and initiate
 anti-biofouling coatings on a diverse range of clinically relevant
 materials. In this research, the aim was to maximise ethylene oxide
 content on a given surface, naturally increasing the hydrophilicity to
 reduce protein adsorption. Firstly, the γ-regime (high pressure and low
 power) was applied to crown ether monomer, to optimise the functional
 group retention and results show the new polymer
 
 coating approached the ethylene oxide retention observed in an industry
 standard coating. In an adjoining study, the ultra-thin industrial
 hyperbranched polyglycerol coating has been rigorously monitored across 7
 different materials, including clinically relevant nitinol stents.
 Vitally, results are presented for the novel application of ion-milling
 X-ray photoelectron spectroscopy, after a protein adsorption test,
 indicating HPG can prevent protein penetration within the coating
 structure. Further evidence for HPG having high non-biofouling capability
 was revealed in biofilm exposure testing that used vibrational
 spectroscopy to define the timepoint of biofilm initiation. While further
 work is required to produce an optimal crown ether plasma polymer coating,
 HPG should soon be suitable for clinical trial.