Immobilization of polymeric nano-assemblies for antibacterial applications

Rigo, Serena. Immobilization of polymeric nano-assemblies for antibacterial applications. 2020, Doctoral Thesis, University of Basel, Faculty of Science.

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Official URL: https://edoc.unibas.ch/79027/

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With conventional antibiotic therapies being increasingly ineffective, bacterial infections with subsequent biofilm formation represent a global threat to human health and therefore,new strategies to fight bacteria colonization need to be found. Coimmobilization of functional, nanosized assemblies broadens the possibility to engineer dually functionalized active surfaces with a nanostructured texture. Surfaces decorated with different nanoassemblies, such as micelles, polymersomes, or nanoparticles are in high demand for various applications ranging from catalysis, biosensing up to antimicrobial surfaces. In this thesis, I present a combination of bio-orthogonal and catalyst-free strain-promoted azide-alkyne click (SPAAC) and thiol-ene reactions to simultaneously coimmobilize various nanoassemblies; polymersome-polymersome and polymersome-micelle assemblies were selected. For the first time, the immobilization method using SPAAC reaction was studied in detail to attach soft, polymeric assemblies on a solid support. Together, the SPAAC and thiol-ene reactions successfully coimmobilized two unique self-assembled structures on the surfaces. Additionally, poly-(dimethylsiloxane) (PDMS)-based polymersomes were used as "ink" for direct immobilization from a PDMS-based microstamp onto a surface creating locally defined patterns. Furthermore, an active and a passive strategy based on polymeric micelles were combined to fight bacterial growth. The passive strategy involved covalent immobilization of polymeric micelles through Michael addition between maleimide exposed micelles and thiol functionalized surfaces. Compared to the bare surface, micelle-decorated surfaces showed reduced adherence and survival of bacteria. To extend this passive defense against bacteria with an active strategy, the immobilized micelles were equipped with the antimicrobial peptide KYE28 (KYEITTIHNLFRKLTHRLFRRNFGYTLR). The peptide interacted nonspecifically with the immobilized micelles where it retained its antimicrobial property. The successful surface decoration with KYE28 was demonstrated by a combination of X-ray photoelectron spectroscopy and quartz crystal microbalance with dissipation monitoring. The initial antimicrobial activity of the nanostructured surfaces against Escherichia coli (E. coli) was found to be increased by the presence of KYE28.
Combining immobilization reactions has the advantage to attach any kind of nanoassembly pairs, resulting in surfaces with desired interfacial properties. Different nanoassemblies that encapsulate multiple active compounds coimmobilized on a surface will pave the way for the development of multifunctional surfaces with controlled properties and effciency. Additionally, the combination of our active and a passive strategy represents a straightforward modular approach that can easily be adapted, for example, by exchanging the antimicrobial peptide to optimize potency against challenging bacterial strains, and/or to simultaneously achieve antimicrobial and anti-infection properties.
Advisors:Palivan, Cornelia G
Committee Members:Textor, Markus
Faculties and Departments:05 Faculty of Science > Departement Chemie > Chemie > Physikalische Chemie (Palivan)
UniBasel Contributors:Palivan, Cornelia G
Item Type:Thesis
Thesis Subtype:Doctoral Thesis
Thesis no:13776
Thesis status:Complete
Number of Pages:112
Identification Number:
  • urn: urn:nbn:ch:bel-bau-diss137763
edoc DOI:
Last Modified:15 Feb 2021 13:04
Deposited On:27 Jan 2021 15:06

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