News: Faculty of Science

A new generation of nanosensors capable of detecting pH inside living cells with previously unseen sensitivity and stability has been developed by a team of scientists from CATRIN, Palacký University Olomouc, and VSB – Technical University of Ostrava, in cooperation with colleagues from Brno University of Technology. The Czech researchers presented the carbon-dot-based sensors, which offer great potential for medical diagnostics, in the journal Biosensors and Bioelectronics.

The pH value is one of the most frequently measured chemical parameters, but the development of nanometric sensors capable of accurately mapping the distribution and dynamics of pH with high spatial and temporal resolution remains a significant challenge. Such sensors are important for our understanding of numerous physiological and pathological processes. The pH value, among other things, has a fundamental effect on enzyme function and influences metabolic and signalling pathways as well as the transport of substances across membranes.

“We were looking for a way to monitor processes inside cells with much higher precision than current probes allow. We have developed a sensor that is small, brightly luminescent, highly stable, and capable of tracking pH changes over an exceptionally wide range. The sensor not only glows under the microscope but also detects pH changes based on fluorescence lifetime, which is a more accurate and reliable parameter than ordinary light intensity,” explained Sergii Kalytchuk, the first author of the study, from CATRIN and the Materials-Environmental Laboratory (MEL) at VSB–TUO.

In contrast to other fluorescent pH sensors, which suffer from gradual photobleaching, chemical degradation, and often require calibration, the new nanosensors maintain excellent performance even under demanding conditions. Their fluorescence lifetime predictably increases with rising pH, which enables direct measurement of cellular acidity – a key parameter closely related to pathological processes such as cancer and neurodegeneration.

“In an experiment with human skin cells, and using advanced microscopy based on fluorescence lifetime imaging (FLIM), the sensors enabled precise mapping of pH inside lysosomes, which are, simply put, the cell’s recycling and cleaning units. Moreover, it was possible to detect pH changes after the application of chemical inhibitors, which opens possibilities for drug testing and for monitoring cellular stress in real time,” said Tomáš Malina, another author of the study.

The development of the sensor took place at the interface of synthetic chemistry and physics, but its application in biomedicine gives the entire work practical significance.

“The study shows how basic materials chemistry can be linked with real biomedical challenges. Thanks to their exceptional photostability, biocompatibility, and extremely wide pH range, these sensors have great potential to become an effective tool for medical diagnostics, including clinical applications,” concluded Radek Zbořil, the corresponding author of the paper.

Over 500 visitors from more than 50 countries came together to meet, share and experience cultural activities, sample diverse cuisines, explore colourful cultural stands and celebrate the vibrant multicultural spirit of Palacký University Olomouc.

The beats of taiko drums blended with the aroma of Vietnamese cuisine, accompanied by children’s laughter and the rustling of Haná folk costumes. The International Haná Festival, jointly organized by the Archdiocesan Charity Olomouc and the Welcome Office at Palacký University Olomouc, became above all a lesson in closeness, in how to meet, listen and learn from one another.

Pavel Flekač, coordinator of the Welcome Office, added, “We wanted the international and domestic students at the university to feel welcome and not far from home, and I believe that this year, with the International Haná festival, we achieved that.”

On stage, European folklore alternated with rhythms and dances from distant lands, while the most engaging moments unfolded beyond the spotlight. At the calligraphy table, visitors patiently practiced their first strokes of Chinese characters; nearby, delicate origami figures took shape. Elsewhere, participants pieced together a map of the USA, guessed Italian regions and tried on traditional Asian garments. Between food stalls, language and children’s workshops thrived, while a photography exhibition quietly told stories of the charity’s projects abroad. Visitors could also mark their home countries on a world map, take pictures in a photo booth or leave a message on community boards.

“It’s great here. It’s a different country, different people, very calm. I’m really enjoying it. The beer is good; it tastes completely different from what I’m used to,” said a student from South Africa.

As the lights dimmed in the evening, one simple certainty remained. Olomouc has the strength to be a city of open exchange. The partnership between the academic and charitable worlds created a platform that connects art, education and civic engagement. Diversity here was a core value throughout the event. And the encounters, both small and large, became a dialogue that will resonate through the city’s streets for a long time to come.

“It is the moments when professional musicians from Czechia play African drums and students from Africa join them, dancing to the rhythms. This is why we do it, because these moments cannot be found anywhere else,” said Alena Vyskočilová, head of the Welcome Office.