Nature Biotechnology: Wireless Smart Bandages!

Some wounds just don't heal.

Diseases such as infections, diabetes, and a suppressed immune system often hinder healing
.
Chronic trauma can last for months and cause anxiety and depression
.
In the worst case, they can be life-threatening
.
The cost of treatment has soared to $25 billion
a year.

Until now, however, solutions to treat chronic wounds have been few, but researchers at Stanford University now report that they have developed a wireless smart bandage that shows promise
in accelerating tissue repair by monitoring the wound healing process and simultaneously treating wounds.
The researchers said the paper, published Nov.
^24th in Natural Biotechnology, their device promotes faster wound closure, increases new blood flow to damaged tissue, and promotes skin recovery
by significantly reducing scarring.

Smart bandages consist of a wireless circuit that uses an impedance/temperature sensor to monitor the progress of
wound healing.
If the wound heals poorly or an infection is detected, the sensor notifies the central processing unit to apply more electrical stimulation to the wound bed to accelerate tissue closure and reduce infection
.
The researchers were able to track sensor data in real time on a smartphone without the need for wires
.

Engineering marvel

The electronic layer, including the microcontroller unit (MCU), radio antenna, memory, electrical stimulator, biosensor and other components, is only 100 microns thick — about the thickness
of a layer of latex paint.

All of the circuitry runs on a cleverly designed hydrogel, a rubbery, skin-like polymer that is integrated to both provide healing electrical stimulation to injured tissue and collect real-time biosensor data
.

The polymers in the hydrogel are designed to safely attach to the wound surface when needed, and when heated to just a few degrees above body temperature (40°C/104°F), they can be pulled out cleanly and gently without causing injury
to the wound.

"When sealing wounds, smart bandages act as they heal," said K.
K.
K.
of the study's co-first author and Stanford School of Engineering.
Yuanwen Jiang, a postdoctoral scholar in the lab of Lee professor of chemical engineering, said
.
"But it's not a passive tool
.
It is an active healing device that can change the standard
of care for chronic wounds.
”

It has previously been reported that electrical stimulation, also known as electrostimulation, can accelerate the migration of keratinocytes to the wound site, limit bacterial infection, prevent the formation of biofilms on the wound surface, thereby actively promoting tissue growth and helping tissue repair
.
Researchers were able to take this well-studied technology and integrate it with real-time biosensor data, providing a new automated treatment modality
informed by biosensors.

The biosensing capabilities of smart bandages can monitor biophysical changes in the local environment, providing a real-time, fast, robust and extremely accurate way to measure wound conditions
.
Technically, smart bandages sense the skin's conductivity and temperature changes as they heal – an increase in electrical impedance as wounds heal and a drop
in local temperature when inflammation subsides.
"The combination of stimulation and perception of a smart bandage accelerates healing, but it can also track wound improvement
.
" Artem Trotsyuk, also one of the study's first authors, said he completed his graduate work in the lab of Geoffrey Gurtner, MD, a former Johnson & Johnson Distinguished Professor of Surgery (emeritus retirement) at the Stanford School of Medicine and currently chair of the Department of Surgery and professor of biomedical engineering at the University of
Arizona in Tucson.
"We believe that it represents a new paradigm that will enable new biological discoveries and the exploration of hypotheses about the healing process in humans that were previously difficult to verify
.
"

Gratifying results, new directions

The researchers took their research a step further, risking understanding why and how electrical stimulation heals wounds
faster.
They now believe electrical stimulation promotes the activation of pro-regenerative genes such as Selenop, an anti-inflammatory gene found to help clear pathogens and heal wounds, and it has been shown to promote muscle and soft tissue growth
.
Similarly, electrical stimulation increases the number of leukocytes, i.
e.
, monocytes and macrophages, by recruiting more M2 anti-inflammatory macrophages, which were previously reported to promote regeneration and play a key role
in the formation of the extracellular matrix required during the proliferative phase of wound healing.

The researchers caution that smart bandages are currently only a proof of concept, albeit promising
.
However, many challenges
remain.
These include increasing the size of equipment to fit human scale, reducing costs, and solving long-term data storage problems – all necessary for mass production if needed and opportunities arise
.
Similarly, new sensors that are not currently integrated, such as those that measure metabolites, biomarkers, and pH
, may be added.
There are also potential barriers in clinical applications, such as hydrogel rejection, where the skin may react to the device and produce a bad gel-skin combination, or biofouling of the sensor, which can lead to irritation
.

Despite these obstacles, researchers are moving forward and optimistic about the potential of their smart bandages to offer hope
to chronic trauma patients.