New chemical reactions are not discovered often. Chemistry, as a science, has had millennia to map the ways that atoms bond, break, and rearrange — and while the field is far from exhausted, genuine discoveries of entirely new reaction classes are rare events.
In March 2026, researchers at **Flinders University** in South Australia published one in ***Nature Chemistry***.
The **trisulfide metathesis reaction** — named for the three-sulfur chains it manipulates — is a chemical process that has never been described in the scientific literature before. And its implications span two of the most urgent material challenges of our time: the global plastic waste crisis and the development of more effective cancer drugs.
**What the Reaction Does**
Sulfur-sulfur bonds appear in peptides, proteins, antibody-drug conjugates, and many pharmaceuticals. The ability to selectively break and reform these bonds — without disturbing the rest of a complex molecule — is enormously valuable for drug developers.
Until now, controlling trisulfide bonds specifically (three sulfur atoms in a chain: S-S-S) has been extraordinarily difficult. The chemistry was messy, producing mixtures of products rather than the single clean compound chemists need.
Professor **Justin Chalker** and his team at the **Chalker Lab** at Flinders University discovered that trisulfide bonds can engage in **metathesis** — they spontaneously exchange sulfur atoms with each other at room temperature, with no heat, no light, and no external reagent required. The reaction runs itself.
More importantly, it runs with **exquisite selectivity**: trisulfide bonds react only with other trisulfide bonds, ignoring other sulfur configurations in the same molecule. This makes it possible to manipulate one specific part of a complex molecule — with surgical precision — without affecting anything else.
**Application One: Better Cancer Drugs**
The immediate pharmaceutical application is the modification of **calicheamicin** — a powerful anti-tumour compound that contains a trisulfide bond. Calicheamicin is already the active payload in **Mylotarg** and **Besylomab**, FDA-approved antibody-drug conjugates used in certain leukaemias.
The trisulfide metathesis reaction provides a route to manipulate the calicheamicin molecule cleanly — potentially enabling a new generation of antibody-drug conjugates with better targeting and fewer side effects.
**Application Two: Infinitely Recyclable Plastics**
Using the reaction, the Flinders team demonstrated the ability to create **polymers** that can be:
🔨 **Moulded** into a product ♻️ **"Unmade"** back into their original building blocks on demand 🔄 **Remoulded** into a new product 🔄 **Repeated indefinitely** — without the polymer degrading or losing properties
Conventional plastic recycling is plagued by **downcycling**: each cycle typically reduces quality, limiting applications. Most plastic can only be recycled a handful of times before it becomes unusable. A truly infinitely recyclable polymer doesn't have this problem — the reversibility is built into the chemical structure.
**Green Chemistry Built In**
Because the reaction runs spontaneously at room temperature — no external energy, no hazardous reagents — it is by definition a green chemistry tool. Its use in manufacturing reduces both cost and environmental footprint simultaneously.
The research was published in ***Nature Chemistry***, supported by an **Australian Research Council Discovery Grant** and international collaboration with researchers at the **University of Liverpool**.
"Our findings show a discovery that could spark rapid advances across multiple fields," said Professor Chalker — from biotechnology and protein science to materials science and pharmaceutical manufacturing.
When a new reaction is found, its full scope often takes years to reveal. The applications to cancer drugs and recyclable plastics are compelling. The applications not yet imagined may prove equally significant. 🧪⚗️♻️
*Sources: Nature Chemistry (March 2026) · Flinders University (news.flinders.edu.au, March 14, 2026) · ScienceAlert · BioEngineer.org · Devdiscourse · Australian Research Council*
