Squishy Lasers Could Reveal Secrets of Cell Growth

Researchers at the University of St. Andrews and the University of Cologne have developed lasers that they have described as “squishy.” These devices could help solve the biological mysteries behind the development of embryos and cancerous tumors.

Fundamental biological processes driven by mechanical forces invisible to the naked eye are currently poorly understood by scientists. The squishy lasers developed by the researchers are able to precisely measure the forces exerted by biological cells.

“Embryos and tumors both start with just a few cells,” said professor Malte Gather from the University of St. Andrews. “It is still very challenging to understand how they expand, contract, squeeze, and fold as they develop. Being able to measure biological forces in real-time could be transformative. It could hold the key to understanding the exact mechanics behind how embryos develop, whether successfully or unsuccessfully, and how cancer grows.”

Researchers from the Universities of St. Andrews and Cologne have developed deformable microlasers capable of measuring force at the cellular level. The advance could lead to a greater understanding of the mechanisms behind cell growth. Courtesy of the University of St. Andrews.

These squishy microlasers can be injected directly into embryos or mixed into artificial tumors. According to Marcel Schubert, a professor at the University of Cologne, the microlasers are actually droplets of oil doped with fluorescent dye.

“As the biological forces get to work, the microlasers are squished and deformed by the cells around them. The laser light changes its color in response and reveals the force that’s acting upon it,” Schubert said.

The innovation allows researchers to measure and monitor biological forces in real time, Schubert said. Additionally, he said, it works in thick biological tissue, an area where other methods would require an almost transparent sample.

The oil and fluorescent dye used to create the microlasers are made from nontoxic, readily available materials, ensuring they do not interfere with biological processes. This aspect makes the technology not only effective but also commercially viable.

The researchers tested their method on fruit fly larvae, to see how they developed, as well as in artificial tumors made from brain tumor cells, so-called tumor spheroids.

“We measured the 3D distribution of forces within tumor spheroids and made high-resolution long-term force measurements within the fruit fly larvae,” Gather said.

The team is now seeking funding to adapt their method for clinical trials, aiming to extend its application to larger cell systems.

The research was published in Light: Science & Applications (www.doi.org/10.1038/s41377-024-01471-9).