Biodegradable Metal-organic Frameworks Composites as Antifouling Coating
Typ
Examensarbete för masterexamen
Master's Thesis
Master's Thesis
Program
Materials engineering (MPAEM), MSc
Publicerad
2023
Författare
Kottan, Nihal
Modellbyggare
Tidskriftstitel
ISSN
Volymtitel
Utgivare
Sammanfattning
Biofilms created by bacteria can cause severe problems in healthcare facilities and
the marine industry. Biofilms impact the effectiveness of antibacterial strategies
and enhance the infectious capability of pathogenic bacteria. Growth cooperation
among marine organisms on biofilms leads to biofouling, resulting in increased fuel
expenditure and loss of function in marine structures. Several examples of mechanobactericidal
materials like vertically oriented graphene, nanorods, etc. have been reported
to reduce biofilm formation. These coatings are manufactured using methods
that are usually unsuitable and expensive for deployments on large surfaces. In this
thesis, we aim to explore the mechano-bactericidal capability of metal-organic frameworks
(MOFs) synthesized using solvothermal method, embedded in biodegradable
polymers, such as polycaprolactone and poly-3-hydroxybutyrate, to develop antibacterial
composites. MOFs like MIL-88B and UiO-66@MIL-88B possess highly defined
edges that can potentially rupture cell membranes. Both selected polymers are enzymatically
degraded by bacteria, show good resistance to hydrolytic degradation,
and are biocompatible. In theory, the degradation of the polymer would clean the
composite surface and expose incoming cells to a fresh layer of MOFs. Pseudomonas
aeruginosa (PA) and Staphylococcus epidermis (SE) were used to evaluate antibacterial
capability, as both bacteria are common pathogens that cause severe infections
in mammals. PA is commonly found in marine environments and is reported to degrade
both selected polymer matrices. Colony-forming unit experiments evaluating
antibacterial efficacy indicated that the tested MOFs could deactivate a large portion
of both Gram-positive and negative inoculum used to test the composite and
scanning electron microscope (SEM) images confirmed the physical penetration of
bacterial cell membranes by MOFs. PA biofilm-induced degradation was studied at
multiple time points using SEM to observe surface changes in the materials. The
results indicate that the MOF-polymer composites are good candidates to reduce
biofilm formation, and with refinement, could potentially be used as antifouling or
medical device coatings.
Beskrivning
Ämne/nyckelord
Metal-organic frameworks , antifouling , antibacterial coatings , biodegradable polymers , mechano-bactericidal , Pseudomonas aeruginosa