The power of polymers

Using cutting-edge techniques, UNSW Professor Cyrille Boyer and his team have developed a more sustainable method of building polymers – chains of small, repeating molecules. The application of this work has led to the design of innovative antimicrobial polymers, which the team are currently investigating. In doing so, they have already developed a process to prepare antimicrobial polymers capable of selectively targeting and eliminating bacteria and fungi. What’s more, the team are also applying their work within the programming of polymer structures to make functional 3D printed materials. These can be used across various applications including the energy and biomedical spaces.

Prof. Cyrille Boyer in his UNSW Chemical Lab.
Image credit: Shyani Seneviratna.

Inspired by the concept of photosynthesis, the process developed by Prof. Boyer leverages the power of visible light to enable the fabrication of new polymers. This allows for complete control over where and when to introduce the next link in a polymer chain, simply by using light. Not only is this an energy-efficient process but allows for the precise crafting and programming of functional polymers and materials.

More importantly, to avoid accumulation in the body or environment at the end of their life, these polymers can also be degraded or disassembled to reform their monomeric constituents.

This pioneering work has since led to the team’s creation of antimicrobial polymers that can target and eliminate bacteria and fungi. "This work started a long time ago and was inspired by natural polymers, such antimicrobial peptides, and our interest in mimicking these compounds using synthetic polymers," says Prof. Boyer. "By optimising the chemical structure of these antimicrobial polymers, such as the type of functional groups, molecular weight, and their hydrophilicity, we’ve been able to reduce the potential side effects, which can cause discomfort and potential problems for patients later in life."

Prof. Boyer believes understanding the connection between polymer structures and bioactivity is a crucial step towards making these polymers even more selective. Part of this includes research into designing polymers aimed at killing bacteria. “We’re trying to mimic antimicrobial peptides, which are natural peptides produced by our immune system that defends us against bacteria and fungi,” he explains. “You can find these peptides everywhere – in plants, animals and humans.”

The challenge is that peptides degrade very quickly if injected. They work very well however because they are produced locally in the body where they’re needed by the immune cells. “They can’t be administered like an antibiotic,” explains Prof. Boyer. “So, by using synthetic polymers as alternatives, we’re looking at whether we can produce them at large scale and improving their stability.”

The other challenge is ensuring that these polymers only target the fungi or bacteria and do not kill or affect the mammalian cells.

With limited drug options and more antibiotic resistance growing each day – not only could Prof. Boyer’s research pave the way for innovative therapeutic solutions, it has the potential to save lives. “In the case of fungi, there are less drugs available on the market and the life expectancy after an invasive infection by fungi is lower,” explains Prof. Boyer. “For example, 40 per cent of people will die from an invasive fungal infection in the blood because this infection typically occurs in patients who already have pre-existing conditions.”

Programming nanostructures in 3D printed materials

Through the ability to precisely prepare functional polymers, Prof. Boyer and his team have also developed a unique 3D printing process that enables them to program the microstructures of 3D polymeric printed materials. This allows for the creation of nanostructured materials with exact accuracy. “3D printing is an emerging technology, with a lot of potential to revolutionize the way we manufacture materials,” he explains. However, despite the ability to control the macrostructure, i.e., shape or size of the object, it can be difficult when using 3D printing to control the nanostructure of items and to create advanced materials. “We’re using functional polymers to make these items more controlled at the nanoscale – so for example you could create objects which have applications within batteries, drug delivery, catalysis, and others.”

Prof. Cyrille Boyer demonstrating the Xube volumetric 3D printer designed by Xolo.
Image credit: Shyani Seneviratna.

These materials have a broad spectrum of applications, including solid polymer electrolytes, drug delivery implants, and advanced ceramics.

“By controlling the nanostructure and the macrostructure at different length scales of the 3D printed materials, we will be able to make more functional objects,” adds Prof. Boyer.

One notable application is the fabrication of drug delivery implants, where the nanostructure of the 3D printed materials dictates the release of therapeutic agents.

Sharing expertise

From design to creation, the research conducted by Prof. Boyer and his team is interdisciplinary. “We partner with researchers in different fields, which allows us to test our solutions to help solve real-world problems,” says Prof. Boyer. This collaborative approach also includes working with researchers locally and overseas. “In our work on antimicrobial polymers targeting fungal infections, we’re working with microbiologists from UNSW (Dr. Megan Lenardon and her group from the School of Biotechnology and Biomolecular Sciences), and the Hans Knöll Institute in Germany (Dr Sascha Brunke and Professor Bernard Hube from the Leibniz Institute for Natural Product Research and Infection Biology)”.

Prof. Boyer hopes to soon develop a library of antimicrobial polymers but first needs to establish the design parameters to synthesise macromolecules necessary to do so.

“By figuring this out – we open a new area where it will be easier to make these compounds, control their functions and see them used in clinics to help patient outcomes.”

- Prof. Boyer