For most people, minor cuts or scrapes are no big deal – the body heals itself quickly, and antibiotics can deal with any infection. But some wounds, such as severe burns and diabetic ulcers, are prone to bacterial infections that may be resistant to antibiotics.
“Diabetes wounds are very difficult to heal and people live with these wounds almost their entire lives,” says Dr. Vitaly KhutorianskyA materials scientist at the University of Reading in the United Kingdom.
To address this problem, scientists are developing new ways to treat infected wounds using specially designed nanomaterials that are activated by light and provide precise antimicrobial action. This approach has shown promise in reducing infection and speeding wound healing in experiments on mice and pigs but has not yet been tested in people.
Chronic, non-healing wounds provide ideal conditions for the formation of resilient biofilms, which delay healing and significantly increase the risk of amputation. The majority of such lesions – more than 78 percent – contain these stubborn layers of bacteria, which are often antibiotic-resistant.
New light-activated nanomaterials offer a different way to eliminate bacterial infections, by converting light into local heat, or by reacting with oxygen present in tissues to produce toxic molecules that kill bacteria with minimal damage to surrounding tissues.
Say, our skin can naturally absorb small amounts of radiation, but with the help of specially designed nanomaterials zhenpeng qin“You can heat the tissue to a higher temperature,” says Richards, a materials scientist at the University of Texas at Dallas. Heat weakens bacteria and helps repair tissues. Kin, who co-wrote it exploration of technology The Annual Review of Biomedical Engineering in 2024 states that similar, light-induced therapy These have been used to deliver toxins to target some skin and esophageal cancers, but have not been applied extensively to wound care.
In a promising study with wounds, rafael mezengaA materials scientist at ETH Zurich and his colleagues started naturally occurring antimicrobial protein It is called lysozyme, which is extracted from egg white. They transformed the protein into a gel mixed with a light-absorbing dye. In the presence of near-infrared light, the dye heats up, melting the gel and releasing the active lysozyme. When the light is turned off and the material is cooled, the lysozyme returns to its inactive form.
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When the team applied the gel to the wounds of rats and pigs, they found that it killed more than 95 percent of the bacteria present. Wounds also healed more quickly, because lysozyme – which is toxic even to healthy cells – was activated in the wound only when exposed to light, saving the skin from overexposure. To further promote healing, the team added magnesium ions to the gel, which induce immune cells called macrophages to shift from an inflammatory state to a healing-promoting state. “Healing will happen much faster because you’ll kill the bacteria and also let the wound heal,” says Mezenga.
Light-activated nanomaterials that release harmful compounds only when and where they are needed could help eliminate wound infections while preventing damage to unaffected tissues. Here, mice with antibiotic-resistant wound infections were treated with a hydrogel that releases lysozyme, an antibacterial protein, only when activated by light. Their wounds healed more quickly than those of mice left untreated or treated with lysozyme alone.
(Image credit: Adapted from Q. Juan et al/Nature Communications and Knoebel Magazine)
Since bacterial biofilms particularly persist on the surfaces of medical implants – where they can cause recurrent infections and sometimes require repeated surgeries or even amputations – the team also tested their gel on infected artificial joints in mice. They injected gel around the infected implanted needle and shone near-infrared light through the skin. The treatment cleared the biofilm and eliminated about 99 percent of the bacteria around the implant while preserving the bone tissue.
In another recent study, scientists from Gannan Medical University and Shanghai University China Wounds are treated using Nanomaterial made of gold nanoparticles and graphene-oxide “quantum dots”,“Which are tiny, carbon-based semiconductor particles. When irradiated with blue light, the gold particles absorb the light energy and convert it to heat, while the graphene oxide helps transfer electrons into the material. This promotes reactions that produce toxic, unstable molecules called reactive oxygen species that react with structures on the bacterial membrane and destroy them.
When scientists added this material to a bacterial solution and shone blue light on it for 10 minutes, the mild heat and reactive oxygen species combined to disintegrate the bacterial membrane. Using a stain that distinguished dead bacteria from live bacteria, the researchers confirmed that the treatment had killed 97 percent of the bacteria.
Testing of the nanomaterial in mice showed that after nine days, wounds on treated mice were 99 percent healed, while wounds on untreated mice were only 70 percent healed.
Although these techniques have shown promise in the laboratory, more work will be needed before they can be applied to people. “There’s still some way to go,” says lars castnerA biologist at Saarland University in Germany. To be useful in a clinical setting, researchers will need to conduct extensive safety testing and lower the cost of nanomaterials, he said.
Still, the idea offers hope for patients with chronic wounds that fail to heal with traditional antibiotics, especially as drug-resistant infections become more common in hospitals and diabetes care.
“It’s a good concept,” says Kin. “Wound healing and antibacterial resistance are huge challenges. And I think any progress we can make in these areas will be welcomed.”
This article was originally published in worth knowing magazine, A non-profit publication dedicated to making scientific knowledge accessible to all. Sign up for Knoebel Magazine’s newsletter.