As the population grows older and diabetes becomes more common, chronic wounds are affecting more people than ever. These slow healing injuries significantly raise the risk of infection, tissue damage, and amputation. Researchers at UC Riverside have developed a new oxygen delivering gel designed to help wounds heal before they progress to limb loss.
A wound that remains open for longer than a month is classified as chronic. Worldwide, about 12 million people experience chronic wounds each year, including roughly 4.5 million in the United States. Approximately one in five of these patients will ultimately face an amputation.
Oxygen Deprivation and Delayed Healing
The research team focused on what they see as a central cause of chronic wounds, a shortage of oxygen deep within damaged tissue. When oxygen levels are too low, wounds stay trapped in a prolonged inflammatory phase. This environment encourages bacterial growth and tissue breakdown instead of repair.
"Chronic wounds don't heal by themselves," said Iman Noshadi, UCR associate professor of bioengineering who led the research team.
"There are four stages to healing chronic wounds: inflammation, vascularization where tissue starts making blood vessels, remodeling, and regeneration or healing. In any of these stages, lack of a stable, consistent oxygen supply is a big problem," he said.
When oxygen from the bloodstream or surrounding air cannot reach the deeper layers of tissue, a condition called hypoxia develops. Hypoxia disrupts the body's normal healing process. The team described its oxygen targeting gel approach in Nature Communications Material.
How the Oxygen Generating Gel Works
The soft and flexible gel is made with water and a choline based liquid that is antibacterial, nontoxic, and biocompatible. When connected to a small battery similar to those found in hearing aids, the material acts like a miniature electrochemical device. It splits water molecules and steadily releases oxygen over time.
Unlike treatments that supply oxygen only at the surface, this gel adapts to the exact shape of a wound. Before it solidifies, it fills small gaps and uneven areas where oxygen levels tend to be lowest and infection risk highest.
Continuous oxygen delivery is critical. The formation of new blood vessels can take weeks, and short bursts of oxygen are not enough to support lasting repair. This system can maintain oxygen flow for up to a month, helping a stalled wound resume a more typical healing pattern.
Promising Results in Diabetic and Older Mice
To test the technology, researchers studied diabetic and older mice because their wounds resemble chronic wounds in older adults. In untreated animals, injuries failed to close and were often fatal. When the oxygen producing patch was applied and replaced weekly, wounds healed in about 23 days and the animals survived.
"We could make this patch as a product where the gel may need to be renewed periodically," said Prince David Okoro, UCR bioengineering doctoral candidate in Noshadi's lab and paper co author.
Balancing Inflammation and Immune Response
The gel may offer more than oxygen support. Choline, one of its main ingredients, helps regulate immune activity and reduce excessive inflammation. Chronic wounds often contain high levels of reactive oxygen species, unstable molecules that damage cells and extend inflammation. By supplying stable oxygen while calming this overactive response, the gel helps restore healthier conditions for tissue repair.
"There are bandages that absorb fluid, and some that release antimicrobial agents," said Okoro. "But none of them really address hypoxia, which is the fundamental problem. We're tackling that directly."
Beyond Wound Care
The potential applications extend past treating chronic wounds. Oxygen and nutrient shortages are major barriers in efforts to grow replacement tissues and organs, which is a long term goal of the Noshadi laboratory.
"When the thickness of a tissue increases, it's hard to diffuse that tissue with what it needs, so cells start dying," Noshadi said. "This project can be seen as a bridge to creating and sustaining larger organs for people in need of them."
Addressing a Growing Health Challenge
Some of the forces behind rising chronic wound rates cannot be solved with a medical device alone. Along with aging and diabetes, lifestyle factors also play a role.
"Our sedentary lifestyles are causing our immune responses to decrease," said UCR bioengineer and co author Baishali Kanjilal. "It's hard to get to societal roots of our problems. But this innovation represents a chance to reduce amputations, improve quality of life, and give the body what it needs to heal itself."
