Presentation by Dr. Susan Kelleher on "Nanostructured Materials for Antibacterial Applications"

The Department of Physics, University of Limerick was delighted to welcome Dr Susan Kelleher, Assistant Professor of Polymer Chemistry at Dublin City University today for her enriching lecture on "Nanostructured Materials for Antibacterial Applications" at the Bernal Institute on 19th April 2023.

ABSTRACT

Resistance to antimicrobial agents has become a major source of morbidity and mortality worldwide and remains a global challenge, with the World Health Organisation launching a global action plan on antimicrobial resistance in 2015. One major issue is that resistance occurs on a molecular level, e.g., ribosomal mutation in the case of aminoglycosides, or the inhibition of enzymes as with sulfonamide analogues, and bacteria can quickly evolve to overcome the effects of antimicrobial agents, while maintaining their aggressiveness. In the case of biofilm-forming bacteria such as Pseudomonas aeruginosa, the inherent nature of the biofilm itself protects the bacteria from antimicrobial agents, enabling them to persist. In the past decade, work by surface scientists has discovered that nano and micron-scale surface topographies can produce antibacterial and antibiofouling effects on materials such as metal, glass, and polymers. With the antibacterial effect, the phenomenon is believed to be due to the physical interaction between the cell membrane and sub-micron topographies, such as pillars and needles. These findings have led to the idea that materials and surfaces which kill bacteria, without the use of chemical agents where resistance is a significant issue, could be a vital tool in the arsenal against bacterial proliferation. Dr Kelleher’s group has studied the topographies present on the wings of cicada insects and showed that the size and shape of the pillars on the surface plays a role in the level of antibacterial activity observed. Furthermore, the group use 2-photon polymerisation and both hard and soft lithography techniques to produce nano- and micro- structured silicon and soft polymeric materials, with a range of nanoscale sized pillars on the surface with excellent control. These surfaces have demonstrated antibacterial activity against Gram-negative and Gram-positive bacteria when compared to planer substrates and have applications for controlled surface-based drug delivery. The group’s work has led to insights into the role bacterial classification and motility play on the antibacterial effect of surface structures.

ABOUT DR KELLEHER

Dr Kelleher completed her degree in Medicinal Chemistry in Trinity College Dublin (2005), after which she carried out her PhD in Organic Chemistry with Dr Paul Evans (2009), as well as a short post-doc in biodegradable chewing gum with Dr Wilhelm Risse, in University College Dublin (UCD). In 2010, she moved to the Technical University Berlin, where she worked on the nano- and micro- surface patterning of biomaterials and investigated the ability of these surfaces to influence cell behaviour with Prof Dr. Marga Lensen. In 2012, Dr Kelleher joined Dublin City University (DCU), where she worked for 2 years on the functionalisation of surfaces and nanoparticles for use in point-of-care devices with Prof Stephen Daniels and in 2014, secured independent funding to begin her own research projects in the areas of bioresponsive materials, nanopatterning and biomimetic engineering. In October 2016, Dr Kelleher was appointed Assistant Professor of Soft Materials in UCD School of Chemistry
and set up the Nanostructured Polymers Group. In February 2021, the group moved to the School of Chemical Sciences in DCU.