What if a simple blood test could reveal not just whether you're sick, but exactly how your cells are struggling? That's the promise of a new method developed by researchers at Stockholm's Karolinska Institutet and SciLifeLab. Their technique, called spectral biophysical cytometry (SBC), uses tiny fluorescent sensors to measure the physical health of individual immune cells — and it can tell the difference between people with atherosclerosis and those without.
Atherosclerosis is a condition where fatty deposits build up in arteries, leading to heart attacks and strokes. The new test works by shining lasers through blood samples and watching how thousands of individual cells respond. The fluorescent nanosensors — essentially microscopic light-up reporters — change color based on the cells' physical properties, like how their outer membranes are structured or how well their mitochondria (the energy factories inside cells) are working.
The researchers tested their method on blood from 38 patients with atherosclerosis and 26 healthy people. The results, published in the journal Nature Nanotechnology, showed clear differences between the two groups. Specifically, the team found changes in how T cells — important immune cells that help coordinate the body's defenses — had altered membrane organization and mitochondrial function. These changes were linked to differences in the cells' lipid (fat) content and which genes were active.
"We show that immune cells in atherosclerosis have altered physical properties that can be measured directly in blood samples, without first needing to analyze genes or proteins," said researcher Erdinc Sezgin of SciLifeLab and Karolinska Institutet's Department of Women's and Children's Health. He described the method as a complement to more time-consuming and costly existing tests.
This matters because current methods for checking cell health often require expensive equipment, lots of time, or complex genetic analysis. SBC aims to be faster and simpler. The team found that the physical properties of cells can signal health status and may even play a role in how diseases develop — not just in atherosclerosis but possibly in other illnesses too.
The study is what's called a proof-of-concept, meaning it's an early step showing the idea works. Next, the researchers plan to test the method on larger groups of patients and explore whether it could help detect or understand other diseases.