Antibiofilm Function-Spacer-Lipid Coatings On Medical Surfaces

Date
2021
Authors
Raghuraman, Pavithra
Supervisor
Henry, Stephen
Williams, Eleanor
Seale, Brent
Item type
Thesis
Degree name
Doctor of Philosophy
Journal Title
Journal ISSN
Volume Title
Publisher
Auckland University of Technology
Abstract

The establishment of bacteria on surgical implants as a biofilm is a major problem and will significantly affect the morbidity and potentially the mortality of the patient. There are two basic approaches to prevent this from occurring being: (i) to prevent it from happening and/or (ii) to treat it afterwards. The first approach is the most desirable.

Surgical implant infections number in the range up to 4% of surgeries and new methods to prevent this are needed. The main objective of this research was to examine the potential of Kode FSL constructs to prevent the establishment of a biofilm. To determine this, FSL antimicrobials needed to be designed and constructed; the ability of the FSL constructs to modify surgical surfaces established and then their ability to prevent the establishment of biofilms evaluated. During the research it was discovered that the best results were obtained by using FSLs to secondarily capture antimicrobials and this new approach was extensively evaluated. It was found that a combined product of crystal violet with silver captured by a charged FSL was the best at exerting significant reduction in adhesion and proliferation of both gram positive (S. aureus and S. epidermidis) and gram negative bacteria (P. aeruginosa and E. coli). FSL captured Cv was effective against gram-positive bacteria and gram-negative E.coli and had no activity against P. aeruginosa. While FSL captured silver nanoparticles were effective against gram-negative P. aeruginosa. FSL captured crystal violet and silver nanoparticle were effective in killing a minimum of 6 log initial bacterial (gram-positive and gram-negative) loading applied to surfaces.

FSL constructs such as FSL-Selenium, FSL-Spermine and FSL-RIP designed for this research, where the antimicrobial agent was a covalent part of the construct were not as good as secondarily captured crystal violet and silver. Among the three FSL’s constructed, only FSL-Se on BAND AID® surfaces at 0.5 mM concentration could bring about an antimicrobial effect against 4.6 log of gram-positive bacterial loadings. While FSL-RIP was able to prevent S. aureus attachment on to surfaces. But no killing effect was observed. Among the three constructs FSL SPM unexpectedly showed enhancement bacterial growth (section 4.1.2.b) rather than inhibition of growth.

Further extension of the work has the potential to result in a novel antimicrobial coating suitable to commodity products such as bandage and surgical implants.

Description
Keywords
Antibiofilm coating , FSL , Crystal violet , Silver nitrate
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