Medical implants constitute an essential advancement in modern medicine, often restoring or replacing functionality to failed organs. Whether a medical implant is temporary or permanent, medical implants carry the risk of implant failure due to an infection. Implant-associated infections (IAI) are challenging to treat and often result in increased medical costs, prolonged hospital stays, implant failure, and, in some instances, severe infections that can lead to amputations, sepsis, or mortality. Eradicating an IAI can be challenging since bacteria can form biofilms on the implant’s surface. The biofilms comprise an extracellular matrix protecting the bacterial cells against systemic antibiotics and the host’s immune system. Treating an IAI usually entails a broad range of antibiotic treatment and surgical procedures for tissue debridement or implant replacement.
For the reasons stated above, scientists and engineers continue to develop technologies to protect the surface of medical implants against infections. Amongst the new technologies, Liquid-Infused Surfaces (LIS) are renowned for their repellent and anti-fouling properties created by tethering a stable liquid layer onto the surface. However, many challenges remain to adopt this technology for implantable devices. For instance, the high repellent properties can hinder implant-tissue interaction and discourage proper integration with the body. Furthermore, the stable liquid layer is contingent on the surface properties of the coated material. In other words, the long-term stability of these coatings may be compromised if the surface chemistry is covered by biological processes such as biofilm formation from adherent bacteria. This thesis aims to expand on the applications of LIS coatings and enhance their properties for implantable materials. This thesis reviews different types of antibiotic surface coatings and further examines LIS technologies as a viable antibacterial coating for medical implants. Then, three novel multifunctional LIS coatings are presented.
The first developed coating enhanced the antibacterial properties of the coating by adding bactericidal agents within the LIS coating. The developed antibiotic liquid-infused coating not only repelled bacteria but also lysed bacteria upon contact. The second coating was designed to promote tissue integration. This multifunctional coating promoted cell deposition and proliferation while remaining repellent toward bacteria, while the conventional LIS coating displayed poor cell availability. Lastly, a collagen-bacteriophage conjugated liquid-infused coating was developed to promote tissue integration while having a two-tier layer of antibacterial protection. This coating was tested in a mouse sepsis model and prevented mortality of all mice, with other groups as high as 90% mortality. These coatings constitute essential steppingstones to bring LIS technology to medical implants. / Dissertation / Doctor of Philosophy (PhD) / Implant-associated infections (IAI) remain a significant problem in modern medicine. IAIs are challenging to treat and often result in increased medical costs, prolonged hospital stays, implant failure, and, in some instances, severe infections that can lead to sepsis or mortality. For these reasons, new technologies have been developed to protect the surface of medical implants against infections. Amongst the new technologies, Liquid-Infused Surfaces (LIS) are renowned for their repellent and anti-fouling properties created by tethering a stable liquid layer onto the surface. This thesis aims to expand on the applications of LIS coatings and enhance their properties for implantable materials. This thesis reviews different types of antibiotic surface coatings, examines LIS technologies, and presents three novel multifunctional LIS coatings. The newly developed coatings enhance the LIS coatings through the addition of antibacterial properties and biomolecules to promote tissue integration.
| Identifer | oai:union.ndltd.org:mcmaster.ca/oai:macsphere.mcmaster.ca:11375/29147 |
| Date | January 2023 |
| Creators | Villegas, Martin |
| Contributors | Didar, Tohid, Biomedical Engineering |
| Source Sets | McMaster University |
| Language | English |
| Detected Language | English |
| Type | Thesis |
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