Background

Gene-editing technology has been recognized as a tool to shift the paradigm of treating genetic diseases, but the problem of non-target tissue exposure after in vivo delivery remains a major obstacle. Existing CRISPR-Cas systems, when injected into the body via adeno-associated virus (AAV) or lipid nanoparticles (LNP), tend to accumulate first in major metabolic organs such as the liver or spleen. This process frequently led to side effects, such as unintended cleavage of intracellular DNA or the induction of immune responses.

While attempts have been made to deliver only to target cells by applying tissue-specific promoters or manipulating viral capsids, there were limitations in fully overcoming the complex in vivo microenvironment. This is because gene-editing molecules, once delivered into the body, often maintained activity even after leaving the target site. Therefore, there was an urgent need for spatiotemporal control technology that could precisely control the timing and location of activation when the gene scissors reach a specific organ or lesion.

Key Findings

The researchers devised a controllable gene-editing system that turns on only at the desired location, using two types of physical stimuli—light and sound waves—as mediators.

The light-regulated system consists of photosensitive protein complexes that respond to specific wavelengths of blue or near-infrared light, coupled to a split Cas protein system. The inactive Cas fragments, which do not bind under normal conditions, recover full cleavage activity when irradiated with light of a specific wavelength, causing them to bind. In tissues with high surface accessibility, such as the skin or eyes, localized gene editing was induced with only a few seconds of light irradiation.

To target deep tissues within the body, focused ultrasound technology, which possesses excellent tissue penetration, was introduced. The researchers designed and attached acoustic-sensitive peptide domains to the enzyme complex, which activate in response to micro-thermal stimulation or mechanical pressure induced by ultrasound. The researchers non-invasively focused ultrasound on deep internal body regions that are difficult for light to reach, such as the deep liver or deep brain, and confirmed that the enzyme structure converted to its active form only in the region where the acoustic focus was formed. In surrounding normal cells, the cleavage enzyme remained in an inactive state, resulting in a reduction of off-target cleavage frequency by more than 80 percent compared to existing constitutively active systems.

Significance and Outlook

This achievement marks a leap forward that could raise the safety standards for gene editing to a new level. Unlike methods that involve administering subsequent drug-degrading or inhibiting proteins to reduce the toxicity of gene editing tools, this technology can dramatically widen the therapeutic safety margin by controlling the activation stage itself from the outside. It also enables the implementation of precision medicine that selectively targets disease areas with clear spatial boundaries, such as cancer tissue or localized inflammatory lesions.

However, technical challenges remain before clinical application. Because the human body has much thicker and more complex tissues than those of small animals, integration with image-guided equipment must precede the accurate delivery of ultrasound foci to deep tissues. In the case of light, due to its shallow tissue penetration depth, minimally invasive procedures such as optical fiber insertion may be inevitable for reaching deep internal regions. Establishing safe output standards to ensure that repeated ultrasound stimulation does not cause micro-damage to surrounding cells is also a task for follow-up research.