Using luminescence to fight bacterial resistance

Yuning Hong has been developing photodynamic therapy - using light to kill bacteria or cancer cells.

Story by Rei Fortes.

Bacteria and other types of pathogens evolve rapidly, making medicines less effective at treating infections over time, and increasing the risk of spreading diseases. Antimicrobial resistance (AMR) is a growing health issue recognised by the World Health Organisation (WHO), which has listed AMR as one of the top 10 global public health threats.

Many nations around the world, including Australia, have developed antimicrobial resistance strategies in order to curb the growth of AMR bacteria. This allows for more research to discover new and efficient methods of reducing AMR bacterial infections such as photodynamic therapy (PDT) using fluorescence.

“Using photodynamic therapy allows you to control the way light is used to activate the process of killing the bacteria, making it more difficult for bacteria to develop a resistance to the light,” says Dr Yuning Hong, a  Senior Lecturer in Chemistry from the La Trobe Institute for Molecular Science (LIMS) at La Trobe University. “This provides more options for researchers to develop anti-bacterial drugs, or use these kinds of methods to treat clinical equipment and avoid bacterial infections.”

“My research focuses on fluorescence materials and how photodynamic therapy creates the possibility of using light to kill bacteria or cancer cells. By modifying the structures of chemical compounds, you can use light to selectively target cancer cells or certain types of bacteria.”

Dr Hong’s research has led her to work with several international institutions. One of her recent projects, in collaboration with a team of researchers from the Ming Wai Lau Centre for Reparative Medicine at the Karolinska Institutet in Hong Kong, focused on using fluorescence with PDT along with a metal complex to determine how to combat the bacteria’s resistance process.

“I wanted to combine these iridium metal complexes, which have a similar kind of PDT properties with other antimicrobial drugs or peptides,” says Dr Hong.

“Combining the molecules gives you a synergy effect to combat the anti-drug resistance. Using fluorescence, you will be able to see where the bacteria are and how much has accumulated on a surface. So, fluorescence is a multifunction method that allows you to see, check and kill bacteria.”

This project contributes to Dr Hong’s research using fluorescence materials in cells working with bacteria as she aims to further the application of the research to specialised medical research areas, such as helping develop stronger antimicrobial drugs.

“We design fluorescence dyes that can be used as a molecular tag which can label damaged proteins and trace where they are, study how they are accumulating, degrading and how they are causing a problem in the cells,” Dr Hong says.

Dr Hong is currently working on another international collaborative research project with colleagues from the China University of Geosciences in Wuhan to develop fluorescence dyes that can target misfolded and unfolded proteins in cancer cells.

“We hope to understand the mechanism in cancer cell deaths and also find a solution to kill cancer cells more specifically with fewer side effects,” says Dr Hong.