Antibacterial elastomeric materials for biomedical applications

Licentiate thesis, 2022

An ageing population in combination with scientific and clinical advancements have led to
a steady increase in the use of medical devices. Elastomeric biomaterials – materials
displaying rubber-like mechanics – have found widespread applicability in the production
of both short- and long-term medical devices. Despite the prevalence of such devices, issues
with medical device-associated infections remain. By surface colonization of bacteria,
systemic infection can arise resulting in patient suffering and increased burden on the
healthcare system. Consequentially, development of antibacterial elastomers capable of
withstanding bacterial surface colonization has been proposed as an effective strategy for
prevention and mitigation of medical device-associated infections.
In this thesis, two alternative strategies to develop antibacterial polydimethylsiloxane
(PDMS) elastomers have been proposed and evaluated. In the first strategy, PDMS surface
modification with multifunctional hydrogel microparticle coating has been developed.
Using a coating of antimicrobial peptide (AMP) RRPRPRPRPWWWW-NH2
functionalized hydrogel particles, high antibacterial activity was reported against
Staphylococcus epidermidis and Staphylococcus aureus. As an additional functionality, the
ability of the coating to encapsulate and release therapeutic substances was investigated,
resulting in a sustained delivery of polar, amphiphilic, and nonpolar drugs.
In the second strategy, modification of bulk PDMS by synthesis of drug-eluting PDMShydrogel
blends was proposed. PDMS and triblock copolymer (diacrylated Pluronic F127,
DA-F127) hydrogel blends were prepared with varying ternary PDMS–DA-F127–H2O
compositions. The test compositions chosen resulted in stable elastomers with tailorable
mechanics and ordered self-assembled nanostructure. The variation in composition offered
potential for sustained delivery of polar and nonpolar drugs, demonstrating potential for
production of drug-eluting and antibacterial elastomeric devices with tailorable mechanics.