RAFT (reversible addition-fragmentation chain transfer) polymerization is an excellent tool for creating polymers. Over the years, we have generated hundreds of different polymer architectures using RAFT polymerization. Particularly attractive is the robustness of the process in the presence of many functional groups, but also the ability to adjust the length and nature of each block. Initially, the work was focused on the synthesis of block copolymers using the RAFT process. Understanding the underpinning mechanism of the RAFT process could determine the success of the block copolymer synthesis. Our main focus is to generate amphiphilic block copolymers, which can self-assemble into micelles, and also cylindrical micelles and vesicles. Crucial is also the design of new polymer structures for emerging applications. The combination of polymerization with click chemistry allows the design of architectures that have never been obtained before.  We also look into techniques to marry synthetic polymers with nature's building blocks such as cellulose, sugars, and proteins. 

Selected publications

• Fundamentals of RAFT polymerization

• When is a process living?

• Polydopamine as photoinitiator

• Making polymers with a hammer

Nature created some very interesting materials that we like to build into our synthetic polymers to achieve both, the flexibility of man-made polymers and the bioactivity and sustainability of nature's building blocks such as sugars, proteins, nanocellulose, and dopamine. Glycopolymers, polymers with attached sugars, are one of our core activities. This is due to the myriad of biological communication events, including cellular recognition, inflammation, signal transmission, and infection by pathogens displayed by them. In the treatment of diseases such as cancer, cytotoxic chemotherapy or radiotherapy can be life-threatening as the therapeutics used are normally not site-specific. Synthesis of glycopolymers has been one of our core activities over the last few years. Our work has two aspects: a theoretical understanding of the relationship between glycopolymer architecture and the rate of receptor binding, and also the practical use of glycopolymers to deliver vaccines or to treat cancer. 

Selected publications

• An introduction to glycopolymers

• Glycopolymers for drug delivery

• Albumin nanoparticles

• Polydopamine nanocapsules based on sugar self-assembly

The self-assembly process is ubiquitous in Nature and occurs in both living organisms (e.g., in cells and organelles to regulate cellular functions) and with innate materials (e.g., regular-shaped objects that organize themselves into a certain arrangement). In our lab, we design polymers comprised of two or more chemically distinct polymer units to impart amphiphilicity into their structure. Over the years, we have also developed an interest in more complicated self-assembly processes (e.g., crystallization-driven self-assembly (CDSA) and hierarchical self-assembly) to generate non-spherical structures such as 2-dimensional (2D) crystalline platelets and multicompartment patchy micelles. Recently, we have moved our activity onto flow-assembly to generate well-defined nanoparticles in a reproducible manner including the flow assembly of single-chain nanoparticles. Flow can be used in a modular setting and the nanoparticles can be further processed downstream and crosslinked with light. Flow analysis can also be attractive when trying to understand how nanoparticles behave in blood

Selected publications

• Polymersomes and stomatocytes in flow

• Charged polymersome in flow

• Non-spherical nanoparticles in flow

• Polymer platelets in blood

• Assembly of single chain nanoparticles in flow

The purpose of nanoparticles is to deliver drugs to specific targets such as a tumour site. There are many reasons to do this such as the insolubility of the drug in aqueous solution, but also to target the drugs to specific tumour sites. Our main aim is to understand how drug loading will influence the properties of nanoparticles. Using NMR and SAXS, we found very interesting relationships that showed how drug loading will change the properties of nanoparticles and therefore their ability to enter cancer cells.

Selected publications

• The Trojan Horse in drug delivery is not really stealth 

• NMR as a tool to show changes in nanoparticle properties

• SAXS to learn more about the inside of drug loaded nanoparticles

How nanoparticles behave in a biological environment is not only important for drug delivery, but also whenever we are in contact with nano-sized plastic, think for example of microplastics where we can find different-sized plastic particles. If nanoparticles enter cells depends on their properties such as the amount of loaded drugs. We therefore study nanoparticles in water but also in biological media where they for example form a protein corona. The nanoparticles are tested using cancer cells and spheroids. Here, we work closely with collaborators such as Prof Kris Kilian to establish new complex models to test nanoparticles, but also with medical experts such as Prof Josh McCarroll, Prof David Ziegler and Prof Orazio Vittorio. 

Selected publications

• Spheroids to evaluate nanoparticles

• Protein corona around nanoparticles

• Effect of drug loading on toxicity of cancer cells

• Effect of drug loading on biodistribution

Can we learn more about our polymers and start making new connections that we could not see before? Polymer discovery is accelerating as we have faster ways of making polymers, such as, for example, flow setups, but we can also analyse polymers quickly as we work hard on high-throughput systems. Hopefully, we can in future predict how much drugs can be loaded into nanoparticles and how large a nanoparticle will be. Ideally, we also like to predict the biological activity. Next to the development of new techniques, we also work with the UNSW AI Institute (Prof Scott Sission) and CSIRO Data 61 (Prof Yanan Fan) to learn more about our polymers.

Selected publications

• Polymer Science and Machine Learning