[Gene Editing. Photo Credit to Pixabay] 

On September 28, 2026, Stanford University researchers announced a new CRISPR (Clustered Regularly Interspaced Short Palindromic Repeats) system that uses light and focused ultrasound to control gene editing in specific parts of the body.

In experiments with living mice, the researchers activated gene editing in selected muscle and brain regions.

The study, published in Cell, demonstrates a possible way to control not only which DNA sequence is edited, but also where and when the editing occurs.

CRISPR is often described as a pair of “molecular scissors” because it can be guided to a specific DNA sequence and change it.

However, choosing the correct DNA target is just one of the many challenges.

For treatments inside the body, scientists also want to make sure that CRISPR becomes active in the right tissue at the right time.

To give CRISPR this extra level of control, the researchers used a small CRISPR protein called Cas12f.

They modified Cas12f so that it would stay mostly inactive until it received a certain type of light.

The new version, called photoswitchable Cas12f, or psCas12f, functions as a gene-editing tool that can be turned on by light.

Because Cas12f is small, the researchers were able to package psCas12f and its guide RNA together inside a single adeno-associated virus, or AAV, commonly used to deliver genetic material into cells.

However, using light inside the body creates another problem.

Light cannot easily travel through deep tissues such as muscle or the brain.

To overcome this, the researchers combined psCas12f with focused ultrasound and special mechanoluminescent particles.

Focused ultrasound can be directed at a small area inside the body without surgery.

When the ultrasound reaches the mechanoluminescent particles, these particles produce light.

That light then activates the psCas12f in the same area.

The process works like a remotely-controlled genetic switch. 

Ultrasound does not directly edit DNA. Instead, it causes the particles to produce light, which activates psCas12f.

By directing ultrasound toward a specific area, researchers can control where and when gene editing takes place.

The researchers tested the system in living mice by delivering psCas12f using AAV.

The researchers first demonstrated that psCas12f could be activated by light in several mouse tissues, including skeletal muscle, the liver, and the brain.

They then tested whether focused ultrasound and mechanoluminescent particles could activate the gene editor in specific locations inside the body.

By directing ultrasound toward selected regions, the researchers successfully produced gene editing in targeted skeletal muscle and brain tissue.

These experiments demonstrated that focused ultrasound, together with light-producing particles, could activate gene editing in targeted regions of the body without directly shining light on those tissues.

To evaluate gene editing, the researchers employed targeted DNA sequencing to analyze changes at specific genetic sequences.

This type of analysis allows scientists to examine changes in DNA, providing direct evidence of gene-editing activity rather than simply showing that the system was activated.

One important finding was that the researchers addressed two challenges in CRISPR technology at the same time.

They developed a light-controlled gene editor small enough to fit with its guide RNA inside a single AAV. 

They also showed that focused ultrasound could activate this system in targeted tissues without requiring surgery to expose those tissues to light.

Previous approaches faced challenges in delivering controllable CRISPR systems using a single AAV and activating them deep inside the body without invasive procedures.

This study demonstrated that combining a compact gene editor with focused ultrasound could help overcome both challenges.

In the future, this added control could enable doctors to activate gene editing primarily in the tissue that needs treatment, rather than allowing the editor to remain active in other parts of the body.

However, the technology is still in an early developmental stage.

The experiments were performed in mice, not humans, so there is still a long way to go before the technique can be applied to humans.

The CRISPR system and the light-producing particles also had to be delivered into the animals before the researchers could control the editing from outside the body.

There are also important questions that still need to be addressed.

Researchers will need to study long-term safety, immune reactions, unintended gene editing, and whether focused ultrasound can provide the same precise control in larger human organs.

Delivery also remains a significant challenge.

A successful treatment would need to safely bring both the gene-editing system and the mechanoluminescent particles to the right places in the human body.

Despite these challenges, the successful gene editing in targeted mouse tissues represents an important step toward controlling CRISPR from outside the body.

Scientists have already developed powerful techniques to decide what DNA sequence to edit. 

This study suggests that researchers may also be able to control where and when the editing happens.

Although more research is needed before the technology can be tested in humans, the results raise an interesting question: Could gene editing one day be as precisely controlled as turning on a light?