You kill the bacteria and heal the wound at the same time’: Emerging nanotech could be the future of wound healing

Researchers are developing light-activated nanomaterials to treat antibiotic-resistant wound infections by converting light into localized heat or toxic molecules. According to studies involving mice and pigs, these materials can eradicate up to 99% of bacteria in specific scenarios, offering a potential alternative for treating chronic wounds like diabetic ulcers.

Chronic, non-healing wounds provide ideal conditions for resilient biofilms. According to the provided research, over 78% of these wounds contain these stubborn bacterial layers, which often resist standard antibiotics and increase the risk of amputation. Vitaliy Khutoryanskiy, a materials scientist at the University of Reading in the United Kingdom, notes that diabetic wounds are particularly difficult to heal, and some patients live with them for the rest of their lives.

Why are chronic wound infections difficult to treat?

The primary obstacle is the formation of biofilms that block traditional treatments. These layers of bacteria protect the infection from antibiotics, stalling the body’s natural repair process. Because these biofilms are persistent, they often lead to recurring infections, particularly on medical implants.

Zhenpeng Qin, a materials scientist at the University of Texas at Dallas, explains that while skin naturally absorbs small amounts of radiation, specially designed nanomaterials allow clinicians to heat tissue to higher temperatures. This heat weakens bacteria and assists in tissue repair. Qin coauthored an exploration of this technique in the 2024 Annual Review of Biomedical Engineering.

How do light-activated nanomaterials work?

These materials function by converting light into heat or reacting with oxygen in tissues to create toxic molecules. This process targets bacteria with minimal damage to surrounding healthy tissue. Different teams are testing different triggers and materials to achieve this.

Raffaele Mezzenga of ETH Zurich and his colleagues developed a gel using lysozyme, an antimicrobial protein extracted from egg whites, mixed with a light-absorbing dye. When exposed to near-infrared light, the dye heats up and melts the gel, releasing the active lysozyme. The protein reverts to an inactive form once the light is turned off and the material cools.

In a separate study, scientists from Gannan Medical University and Shanghai University in China used gold nanoparticles and graphene-oxide “quantum dots.” When irradiated with blue light, the gold particles create heat while the graphene oxide transfers electrons. This combination produces reactive oxygen species that destroy bacterial membranes.

What results have researchers seen in animal trials?

The ETH Zurich team found their lysozyme gel eradicated more than 95% of bacteria in mice and pigs. To speed up recovery, Mezzenga added magnesium ions to the gel, which prompt macrophages to shift from an inflammatory state to a healing state. Mezzenga stated that healing is faster because the treatment kills bacteria and heals the wound simultaneously.

This gel also showed success with medical implants. When injected around an infected implanted needle in mice and treated with near-infrared light, the gel cleared biofilms and killed about 99% of bacteria while preserving bone tissue.

The Chinese research team observed that after 10 minutes of blue light exposure, 97% of bacteria in a solution were killed. In mouse trials, treated wounds showed 99% healing after nine days, compared to about 70% healing in untreated mice.

What happens next for this technology?

These techniques have not yet been tested in humans. Lars Kaestner, a biologist at Saarland University in Germany, warns that there is still some way to go before clinical application. He notes that researchers may need to conduct extensive safety testing and find ways to lower the cost of the nanomaterials.

If safety and cost hurdles are cleared, this technology could provide a new option for patients in hospital and diabetic care settings where drug-resistant infections are increasingly common. Qin describes the concept as a welcome advance in the face of the “very big challenges” of wound healing and antibacterial resistance.

Frequently Asked Questions

What is lysozyme and where does it come from?
Lysozyme is a naturally occurring antimicrobial protein that is extracted from egg whites.

Have these light-activated treatments been used in humans?
No. While the approach has shown promise in experiments on mice and pigs, it has not yet been tested in people.

How does the blue light treatment from the Chinese study work?
It uses gold nanoparticles and graphene-oxide quantum dots. The blue light causes the gold to generate heat and the graphene oxide to help produce reactive oxygen species, which together destroy bacterial membranes.

Do you believe light-based therapies could eventually replace traditional antibiotics for wound care?