MIT scientists shone patterned light on starfish egg cells carrying a modified enzyme; the cells moved and changed shape, and some were stretched into squares

Scientists have found a way to physically reshape living cells using nothing but light. Researchers caused starfish egg cells containing a modified enzyme to move and change shape after exposing them to patterned light, according to MIT News. Some cells were even elongated into square shapes. This is based on a 2025 paper titled "Light-induced cortical excitability reveals programmable shape dynamics in starfish oocytes," published in the journal Nature Physics. Although quite a showy title, the study aims to understand how cells can be instructed to change shape and whether humans will one day be able to programme them.

How can light guide cells?

Scientists modified an enzyme known as GEF, responsible for activating a protein called Rho, which can help regulate cell mechanics. They engineered a light-sensitive version of this enzyme, extracted its mRNA, and injected that mRNA directly into starfish egg cells taken from one ovary. Once inside the cells, the mRNA caused the cells to start producing the light-sensitive enzyme themselves, per the MIT News article. it into starfish egg cells taken from one ovary, causing the cells to produce the enzyme, per the MIT News article.

When exposed to light, certain areas activated the enzyme, causing Rho to gather in certain areas. This caused muscle-like fibres to pull the cell into different shapes depending on where the light had been applied. These eggs came from the starfish Patiria miniata, according to a 2025 LMU Munich publication; LMU Munich was a partner in the research.

Using light to control biological systems isn’t a new concept

A 2005 paper titled “Millisecond-timescale, genetically-targeted optical control of neural activity,” by Boyden and colleagues, published in the journal Nature Neuroscience, showed how researchers could use a light-sensitive protein from algae, known as Channelrhodopsin-2, to control the firing of neurons in mammals on a millisecond scale. This type of research is known as optogenetics. The starfish egg cells take inspiration from this research, but instead of affecting the electrical signals in cells, the light is affecting the physical shape.

Square shapes aren’t the only shapes

The deformations observed ranged from localized pinching and squaring to traveling contraction waves and, in some cases, lysis (bursting) of the cell, as reported by LMU Munich and the arXiv preprint of the paper. A model was developed to distinguish between guided deformations (localized, shaped by where the light fell) and unguided ones. Using a single source of light, researchers found that contractions could be triggered across the whole cell once the enzyme reached a certain concentration. Nikta Fakhri, the paper's senior author, explains that this creates "a system where we can trigger a large all-or-nothing response using a small stimulus at just the right time."

The pitch and the fine print

The applications of this research are the part that will most likely go viral. The researchers suggest that this could be used to create cells that act like patches. When exposed to light, the cells contract, helping to seal wounds. Drug-containing cells could be created that only release their contents when exposed to light in certain areas of the body. “We have created a blueprint for designing programmable synthetic cells”, Fakhri explains.

However, this research suggests that the research “could” be used to help guide these ideas. LMU Munich noted that the research was carried out on egg cells from an individual organism, and describes the work's applications in synthetic biology as "potential" rather than demonstrated. The findings point toward future possibilities; they don't describe anything that has actually been built yet. There is a long way to go from a petri dish to living cells in the body, and none of the sources claim that step has been taken.

Why it still matters

Given how quickly health technology headlines tend to get overhyped, it's reasonable to approach this with some skepticism. Still, it's worth noting how this research, funded partly by the Sloan Foundation and the National Science Foundation, according to MIT News, was carried out. It's basic research, aimed at understanding how cells function, not at delivering a finished product.

On that front, it succeeds: the study shows that cells can be reshaped in real time using a light-activated switch. "This work demonstrates how we can use a light-activated switch to dynamically reshape cells and reveals basic design principles," Fakhri says. Whether this will ever help heal wounds or deliver drugs remains to be seen. But it does show just how flexible living cells can be, enough that a small egg cell was coaxed into becoming a square.