Multimodal “barcode” enables detection of senescent cells

Some cells enter a state known as cellular senescence as they age. In this state, the cells stop dividing but do not die. These cells may be associated with inflammation, tissue damage and age-related diseases, but they also perform essential functions in the body, including contributing to embryonic development and tissue repair. Understanding where senescent cells emerge and what causes them to develop is therefore important.

A team of scientists at the Massachusetts Institute of Technology used Raman microscopy, a technique in which light scattered by cells reveals information about their chemical composition. The researchers compared these data with gene activity in skin and lung tissues from young and aged mice.

They found increased production and accumulation of lipids in senescent cells. However, the cellular signatures varied between organs. In the skin, for example, the changes were associated with processes involving collagen, while the lungs showed stronger signals linked to inflammation.

By combining chemical signals with gene activity data, the researchers identified a set of distinctive features of senescent cells, which they called a multimodal barcode.

The barcode is based on specific peaks in the Raman spectrum, each associated with particular chemical compounds or molecular types. This allows senescent cells to be distinguished from other cells.

Combining chemical and genetic signatures enabled the researchers to create the multimodal barcode for senescent cells. At present, analyzing a tissue sample measuring about 1 square millimeter can take up to 30 hours, but the researchers plan to accelerate the process and adapt the method for use in humans.

In the future, the multimodal barcode could potentially be integrated into an endoscope to detect senescent cells directly inside the human body.