Antimicrobial resistance (AMR) is currently one of the greatest threats to global health and could cause 10 million deaths per year by 2050 if no action is taken. A study from the University of Aveiro (UA) highlights the urgent need for new solutions, exploring an innovative approach to fighting bacteria through therapeutic alternatives to traditional methods. The research focuses on photodynamic inactivation, a technique that uses light, oxygen and specific molecules — known as photosensitizers (PS) — capable of generating cytotoxic species that destroy microorganisms. It is a non-invasive, safe method that can be repeated several times while maintaining its effectiveness.
Authored by researchers Sara Gamelas, Raquel Tavares, Inês Chaves, Amparo Faustino and Leandro Lourenço, from the Associated Laboratory for Green Chemistry (LAQV-REQUIMTE), and Adelaide Almeida, researcher at the Centre for Environmental and Marine Studies (CESAM) and professor at the Department of Biology of the University of Aveiro, the study developed two new molecules (H2Por and ZnPor), belonging to the porphyrin family. These stable molecules, which have been explored by the research group, maintain their antimicrobial performance when exposed to light.
When these molecules are exposed to white light, they temporarily generate new chemical species capable of damaging and destroying bacteria. In tests carried out with the bacterium Escherichia coli — responsible for numerous infections — the results were highly promising: even when low doses of PS were used, it was possible to effectively eliminate the bacteria present, reaching the detection limit of the method used to quantify the bacterium (99.999%).
The UA scientists also observed that adding a salt such as potassium iodide significantly increases the effectiveness of the process. With this combination, it is possible to reduce the time needed to eradicate this bacterium to just 15 minutes, lower the amount of energy required, or optimize the dose of the molecules used — all important factors for future practical applications.
Another relevant aspect, the researchers point out, is that this approach works with low doses of light and active compounds, which represents a significant advantage for potential clinical applications, making the process safer and more efficient.
According to criteria used by the international scientific community to define antibacterial agents, the results obtained place these molecules in the class of promising antibacterial agents, with high levels of effectiveness in eliminating bacteria. In addition, their preparation and properties reinforce their potential use not only in healthcare, but also in environmental contexts.
This study therefore opens up new perspectives in the fight against infections caused by resistant bacteria, pointing to alternatives to antibiotics at a time when their effectiveness is increasingly compromised.
Original news item: UA Notícias, 1 June 2026