Sept. 6, 2023 — You cut yourself. You put on a bandage. In a week or so, your wound heals.
Most people take this routine for granted. But for the more than 8.2 million Americans who have chronic wounds, it’s not so simple.
Traumatic injuries, post-surgical complications, advanced age, and chronic illnesses like diabetes and vascular disease can all disrupt the delicate healing process, leading to wounds that last months or years.
Left untreated, about 30% lead to amputation. And recent studies show the risk of dying from a chronic wound complication within 5 years rivals that of most cancers.
Yet until recently, medical technology had not kept up with what experts say is a snowballing threat to public health.
“Wound care — even with all of the billions of products that are sold — still exists on kind of a medieval level,” said Geoffrey Gurtner, MD, chair of the department of surgery and professor of biomedical engineering at the University of Arizona College of Medicine. “We’re still putting on poultices and salves … and when it comes to diagnosing infection, it’s really an art. I think we can do better.”
Old-School Bandage Meets AI
Gurtner is among dozens of clinicians and researchers reimagining the humble bandage — combining cutting-edge materials science with artificial intelligence, or AI, and patient data to develop “smart bandages” that do far more than shield a wound.
Someday soon, these paper-thin bandages embedded with miniaturized electronics could monitor the healing process in real time, alerting the patient — or a doctor— when things go wrong. With the press of a smartphone button, that bandage could deliver medicine to fight an infection or an electrical pulse to stimulate healing.
Some “closed-loop” designs need no prompting, instead monitoring the wound and automatically giving it what it needs.
Others in development could halt a battlefield wound from hemorrhaging or kick-start healing in a blast wound, preventing longer-term disability.
The same technologies could — if the price is right — speed up healing and reduce scarring in minor cuts and scrapes, too, said Gurtner.
And unlike many cutting-edge medical innovations, these next-generation bandages could be made relatively cheaply and benefit some of the most vulnerable populations, including older adults, people with low incomes, and those in developing countries.
They could also save the health care system money, as the U.S. spends more than $28 billion annually treating chronic wounds.
“This is a condition that many patients find shameful and embarrassing, so there hasn’t been a lot of advocacy,” said Gurtner, outgoing board president of the Wound Healing Society. “It’s a relatively ignored problem afflicting an underserved population that has a huge cost. It’s a perfect storm.”
How Wounds Heal, or Don’t
Wound healing is one of the most complex processes in the human body.
First platelets rush to the injury, prompting blood to clot. Then immune cells emit compounds called inflammatory cytokines, helping to fight off pathogens and keep infection at bay. Other compounds, including nitric oxide, spark the growth of new blood vessels and collagen to rebuild skin and connective tissue. As inflammation slows and stops, the flesh continues to reform.
But some conditions can stall the process, often in the inflammatory stage.
In people with diabetes, high glucose levels and poor circulation tend to sabotage the process. And people with nerve damage from spinal cord injuries, diabetes, or other ailments may not be able to feel it when a wound is getting worse or reinjured.
“We end up with patients going months with open wounds that are festering and infected,” said Roslyn Rivkah Isseroff, MD, professor of dermatology at the University of California Davis and head of the VA Northern California Health Care System’s wound healing clinic. “The patients are upset with the smell. These open ulcers put the patient at risk for systemic infection, like sepsis.” It can impact mental health, draining the patient’s ability to care for their wound.
“We see them once a week and send them home and say change your dressing every day, and they say, ‘I can barely move. I can’t do this,’” said Isseroff.
Checking for infection means removing bandages and culturing the wound. That can be painful, and results take time.
A lot can happen to a wound in a week.
“Sometimes, they come back and it’s a disaster and they have to be admitted to the ER or even get an amputation,” Gurtner said.
People who are housing insecure or lack access to health care are even more vulnerable to complications.
“If you had the ability to say ‘there is something bad happening,’ you could do a lot to prevent this cascade and downward spiral.”
Bandages 2.0
In 2019, the Defense Advanced Research Projects Agency (DARPA) — the research arm of the Department of Defense — launched the Bioelectronics for Tissue Regeneration (BETR) program to encourage scientists to develop a “closed-loop” bandage capable of both monitoring and hastening healing.
Tens of millions in funding has kick-started a flood of innovation since.
“It’s kind of a race to the finish,” said Marco Rolandi, PhD, associate professor of electrical and computer engineering at the University of California Santa Cruz and the principal investigator for a team including engineers, medical doctors, and computer scientists from UC Santa Cruz, UC Davis, and Tufts. “I’ve been amazed and impressed at all the work coming out.”
His team’s goal is to cut healing time in half by using (a) real-time monitoring of how a wound is healing – using indicators like temperature, pH level, oxygen, moisture, glucose, electrical activity, and certain proteins, and (b) appropriate stimulation.
“Every wound is different, so there is no one solution,” said Isseroff, the team’s clinical lead. “The idea is that it will be able to sense different parameters unique to the wound, use AI to figure out what stage it is in, and provide the right stimulus to kick it out of that stalled stage.”
The team has developed a proof-of-concept prototype: a bandage embedded with a tiny camera that takes pictures and transmits them to a computer algorithm to assess the wound’s progress. Miniaturized battery-powered actuators, or motors, automatically deliver medication.
Phase I trials in rodents went well, Rolandi said. The team is now testing the bandage on pigs.
Across the globe, other promising developments are underway.
In a scientific paper published in May, researchers at the University of Glasgow, Scotland, described a new “low-cost, environmentally friendly” bandage embedded with light-emitting diodes (LEDs) that use ultraviolet light to kill bacteria — no antibiotics needed. The fabric is stitched with a slim, flexible coil that powers the lights without a battery using wireless power transfer. In lab studies, it eradicated gram-negative bacteria (some of the nastiest bugs) in 6 hours.
Also in May, in the journal Bioactive Materials, a Penn State team detailed a bandage with medicine-injecting microneedles that can halt bleeding immediately after injury. In lab and animal tests, it reduced clotting time from 11.5 minutes to 1.3 minutes and bleeding by 90%.
“With hemorrhaging injuries, it is often the loss of blood — not the injury itself — that causes death,” said study author Amir Sheikhi, PhD, assistant professor of chemical and biomedical engineering at Penn State. “Those 10 minutes could be the difference between life and death.”
Another smart bandage, developed at Northwestern University, harmlessly dissolves — electrodes and all — into the body after it is no longer needed, eliminating what can be a painful removal.
Guillermo Ameer, DSc, a study author reporting on the technology in Science Advances, hopes it could be made cheaply and used in developing countries.
“We’d like to create something that you could use in your home, even in a very remote village,” said Ameer, professor of biomedical engineering at Northwestern.
Timeline for Clinical Use
These are early days for the smart bandage, scientists say. Most studies have been in rodents and more work is needed to develop human-scale bandages, reduce cost, solve long-term data storage, and ensure material adheres well without irritating the skin.
But Gurtner is hopeful that some iteration could be used in clinical practice within a few years.
In May, he and colleagues at Stanford University published a paper in Nature Biotechnology describing their smart bandage. It includes a microcontroller unit, a radio antenna, biosensors, and an electrical stimulator all affixed to a rubbery, skin-like polymer (or hydrogel) about the thickness of a single coat of latex paint.
The bandage senses changes in temperature and electrical conductivity as the wound heals. And it gives electrical stimulation to accelerate healing.
Animals treated with the bandage healed 25% faster, with 50% less scarring.
Electrical currents are already used for wound healing in clinical practice, Gurtner said. Because the stimulus is already approved and the cost to make the bandage could be low (as little as $10 to $50), he believes it could be ushered through the approval processes relatively quickly.
“Is this the ultimate embodiment of all the bells and whistles that are possible in a smart bandage? No. Not yet,” he said. “But we think it will help people. And right now, that’s good enough.”
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2023-09-06 21:33:00
