Across the world, scientists are still trying to answer one of medicine’s most difficult questions: how can we safely and effectively treat brain cancers such as glioma? Despite decades of effort, outcomes for people diagnosed with high-grade glioma remain bleak. Current treatments, including surgery, radiotherapy, and chemotherapy, can slow the disease, but rarely stop it. The GlioLighT consortium, a multidisciplinary European research team funded by the European Innovation Council, has come together to explore a novel approach based on direct light therapy. Being in a very early stage, the project doesn’t promise an immediate cure; instead, it sets out to answer a very fundamental question: can light itself trigger biological processes that might form the basis of a safe and targeted brain tumor therapy? More
At the heart of GlioLighT is a scientific curiosity about how certain wavelengths of light interact with living tissue. The project investigates a novel concept called Direct Light Therapy (or DLT for short). DLT uses infrared light, specifically at a wavelength of 1267 nanometres, to stimulate chemical reactions inside cells.
This is not the same as standard laser surgery or even existing photodynamic therapies that use drugs, so-called photo-sensitisers, to make tumours light-sensitive. DLT is distinctive because it aims to generate reactive oxygen species, especially singlet oxygen, directly within the treated cells, without adding any drugs at all.
The idea is to induce the controlled production of reactive oxygen species, which might trigger a response in cancer cells that lead to their destruction, without having significant negative effects on nearby healthy cells. But the real scientific questions lie in the details: how does this process occur, how deeply does the light penetrate tissue, and what happens to both cancerous and healthy brain cells when they are exposed to it?
GlioLighT’s goal is not to develop a therapy for patients right now, but to lay the scientific and technological groundwork that future researchers could build upon. Light-based medicine has been studied for decades. In conventional photodynamic therapy (or PDT for short), patients receive a photo-sensitiser drug, which, once inside the body, reacts when illuminated to produce reactive oxygen species that can damage cancer cells. PDT is used for some skin and internal cancers, but its usefulness in the brain is limited.
Photo-sensitising drugs are often toxic, difficult to handle, and unable to cross the blood–brain barrier, meaning the natural defence system that shields the brain from harmful substances. Furthermore, the wavelengths of light used in PDT do not travel very far through tissue, which restricts the treatment to small or exposed tumours.
By contrast, DLT uses longer-wavelength infrared light that can travel deeper into tissue, and its induced effects do not depend on a drug. This could, in theory, make it possible to target tumours in regions of the brain that are currently inaccessible to light-based treatments. However, this remains a hypothesis: one that GlioLighT intends to test rigorously from multiple scientific angles.
GlioLighT brings together experts in photonics, neuroscience, oncology, and biomedical engineering from institutions across Europe, each contributing specialised skills. The project unfolds across several main research objectives.
At Aston University in the UK, physicists are creating advanced ultra-short pulse lasers that can deliver extremely brief, precisely controlled bursts of 1267-nm light. These devices are designed to minimise heat and maximise control, allowing researchers to study biological effects without damaging tissue through temperature changes.
At the University of Mainz, in Germany, and the University of Barcelona, in Spain, biologists and neuroscientists are exposing tumour cells, immune cells, and healthy brain cells to different doses of light. They investigate what happens at the cellular level, such as whether singlet oxygen is produced, which kinds of cell death are triggered, whether energy production in mitochondria changes, and how immune cells respond.
Engineers at Ludwig-Maximilians University Munich, in Germany, and the Finnish company Modulight in Tampere are designing a preclinical GlioLighT delivery/sensing system, which is a prototype system that combines fibre-optic light delivery with sensors that can monitor tissue temperature, singlet oxygen levels, and light distribution in real time. This system will first be tested in artificial “phantom” models that mimic the optical properties of brain tissue.
Only after these laboratory and model experiments will the team proceed to preclinical studies in mice. These carefully controlled studies will help them understand how light travels through brain tissue, what biological effects occur, and how safety can be maintained. Mathematical and computational models will then be built to simulate how the technique might behave in human tissue, though no clinical use is planned within the project.
GlioLighT’s work sits firmly in the discovery phase of research. Their aim is to gather reliable, mechanistic knowledge, the kind that paves the way for future investigators to decide whether DLT is worth pursuing further toward clinical trials.
In many ways, this makes the project even more exciting: it’s not a race to a product, but an exploration of how light interacts with the living brain at a fundamental level. The questions being asked are as much about physics and physiology as they are about oncology.
Some intriguing questions that the project may shed light on include determining whether, and which type of, reactive oxygen species can be reliably generated in living tissue without drugs, establishing differences between the effects of DLT and conventional PDT, and assessing how various cell types found in the brain respond to repeated exposure to infrared light.
One critical output of the project is unravelling the respective potentials of DLT and PDT to strengthen the anti-tumour capacities of the immune cells that infiltrate brain tumours. Another valuable output will be the leaps in knowledge gained about neuronal functions and their reaction to DLT, which will have applications far beyond glioblastoma in a variety of neurodegenerative disease research.
The team is acutely aware of the ethical and social responsibility that comes with biomedical innovation. GlioLighT explicitly avoids overstating its potential clinical impact and focuses instead on building a foundation of understanding. Every experiment, from in-vitro cell tests to animal studies, follows strict ethical and welfare standards.
By the end of the project in December of 2026, GlioLighT aims to have achieved a working prototype of a safe, controllable 1267-nm laser system suitable for further biological research, along with a detailed understanding of how DLT affects tumour and healthy brain cells at the molecular and cellular levels. The consortium will also create an open repository of data and models that other researchers can use to advance the field.
What GlioLighT offers today is a disciplined, transparent exploration – one that could inform the next generation of photonic approaches to cancer treatment.
No one can say yet whether shining infrared light into the brain will become part of tomorrow’s cancer toolkit. But by methodically testing the idea, refining the technology, and sharing their findings openly, the GlioLighT consortium ensures that the conversation is guided by evidence, not speculation.
