Curiosity about how nature’s own molecules can be turned into useful tools has led scientists to develop new “smart” materials made from cinchona alkaloids — a family of plant compounds once prized for treating malaria and heart conditions. These tiny materials behave almost like chemical computers, lighting up or changing color to reveal the presence of certain substances.
The research was conducted by Nicola’ Agius and Professor David Magri of the University of Malta and Catherine Ashton and Dr. Helen Willcock of Loughborough University. Their work, published in the journal RSC Advances, shows how molecules inspired by nature can be redesigned into intelligent materials capable of detecting minerals essential to human health.
Professor Magri said that the team “demonstrated fluorescent natural product-based polymers as sustainably sourced intelligent materials,” highlighting their aim to create sensing technologies that are effective yet environmentally responsible.
Professor Magri’s team blended the cinchona alkaloids — quinidine, quinine, cinchonine, and cinchonidine — with the water-compatible chemical, acrylamide, to create four new polymers. Each polymer is unimaginably small, thousands of times thinner than a human hair, yet it shines with a vivid blue glow under ultraviolet light, a type of invisible radiation that makes fluorescent substances visible to humans. This glow shows that the natural sparkle of the alkaloids is preserved, even after being woven into a long polymer chain — a structure built by linking many small molecules together in sequence.
During laboratory tests, the polymers behaved like tiny logic circuits. They lit up in acidic conditions but went dark when salts such as chloride, bromide, or iodide were added. When both acid and iodide were present together in water, the material changed from colorless to yellow, effectively performing an “AND” operation — a logic term borrowed from computing that means both conditions must be met to produce a result. This visible transformation makes iodide detection as simple as watching a liquid change color.
Professor Magri explained that iodide is an essential mineral for human health, helping to prevent thyroid-related diseases like goiter. “Governmental health departments could find this technology useful for ensuring food and beverage producers adhere to the strict guidelines for iodide content in drinking water and foodstuffs,” he said.
The color change, the team discovered, comes from a delicate electrical attraction known as a pi–anion interaction. In simple terms, it is a weak but important pull between negatively charged iodide ions and positively charged regions within the polymer. This gentle tug shifts the way electrons move inside the macromolecule, making it absorb and reflect light differently — which our eyes see as yellow.
Interestingly, the cinchona-based polymers turned out to be more responsive than their simpler, single-molecule versions. They detected iodide even in trace amounts and did so quickly. This happens because the charged environment of the polymer boosts these subtle electrical effects, allowing the chemical response to become amplified and easier to observe.
Equally important, the researchers confirmed that the brightness of the quinidine and quinine polymers was just as intense as that of the original natural molecules. In other words, turning them into polymers did not dim their glow. Quinine’s distinctive blue fluorescence — long used as a reference in photochemistry to measure light emission — remains as bright in these new materials as it does in nature.
Beyond the laboratory, this work points to a broader idea: chemistry can be used to mimic the decision-making logic of computers. The concept, known as molecular logic, uses changes in light or color to signal a result, much like digital electronics use ones and zeros. By converting simple chemical inputs such as acidity or salt concentration into visible color outputs, these smart materials could form the basis of future sensors for medical testing, environmental monitoring, or even molecular-scale computing systems.
Looking ahead, Magri and his team hope to deepen their understanding of how these molecular interactions produce such clear visual effects. They also plan to adapt the same approach to detect other biologically or environmentally important ions. “Studies are currently underway to better understand this supramolecular interaction,” the researchers explained — referring to how molecules organize and communicate without forming direct chemical bonds. Their ongoing work reflects a growing movement in chemistry toward smart, sustainable materials that learn from nature yet serve modern needs.
Journal Reference
Agius, Nicola’; Ashton, Catherine J.; Willcock, Helen; and Magri, David C. “Cinchona alkaloid copolymers as fluorimetric INHIBIT and colorimetric AND logic gates for detection of iodide.” RSC Advances, 2025. DOI: https://doi.org/10.1039/d5ra01281c
About the Authors
Nicola’ Agius completed her undergraduate studies and Master’s in Chemistry by Research with Prof. David C. Magri studying fluorescent natural product-based polymeric logic gates. She has industry experience through placements at Trelleborg Sealing Solutions and Smart Materials Ltd., an auxetic foam start-up. She joined the Calvino Group as an intern investigating responsive polymer networks as reversible dual-stimuli smart materials. Her academic achievements include the Dean’s Award for Master’s Distinction, the Medichem Prize for Organic Chemistry and the Torrent Prize for Analytical Chemistry. Nicola’ is beginning her PhD in Metamaterials at the University of Malta developing shape morphing polymers.
Dr. Caty Ashton is a Senior Biochemistry Research Technician at Lancaster Environment Centre, Lancaster University. She completed her Master’s in Chemistry at Lancaster University, and her PhD in Chemistry and Materials Engineering at Loughborough University. Her PhD focussed on developing macromolecular MRI and optical imaging agents. After a change of discipline, Caty now works in Biochemistry, analysing proteins and enzymes which are key to the photosynthesis mechanism, to contribute towards making cowpea and soybean crops more productive and climate resistant.
Helen Willcock is a Senior Lecturer within Materials at Loughborough University, leading a diverse and multidisciplinary group focused on the control of polymer properties by tuning architecture and functionality. Helen’s research focusses on the development of polymer particles and nanocomposites, particularly for sensing and imaging applications. She has extensive experience in working with Industry and was part of the team that won the RSC Industry-Academia Collaboration Award in 2018. She is the chair of Macro Group UK – the Royal Society of Chemistry (RSC) & Society of Chemical Industry (SCI) Pure and Applied Macromolecular Chemistry Group.
David Magri is a Professor at the University of Malta leading a research team developing intelligent logic-based molecules and materials. He obtained his BSc Hons (4-year) and PhD at Western University in London, Ontario Canada and was a post-doctorate researcher at Queen’s University Belfast in Northern Ireland with Prof. A. P. de Silva. After teaching in Canada for four years at the University of Prince Edward Island, Ontario Tech University and Acadia University, he travelled to the archipelago Republic of Malta located in the Mediterranean Sea. He is a twice recipient of a Malta Science Innovation Award. At the 8th International Conference on Molecular Sensors and Molecular Logic Gates in Shanghai, China in October 2025, he was a recipient of the Czarnik Emerging Investigator Award.
