Artificial Skin Advancements

In the 1970s, Massachusetts Institute of Technology professor Ioannia Yannas discovered a way to regenerate human skin cells, a critical innovation seeing as bandages alone are often incapable of sealing large, damaged areas of the skin. In the time since Yannas’s initial work, the development of skin-like electronics has improved dramatically, increasing a victim’s chance of survival as well as the rate at which healing can occur.1

Before designing artificial skin began development, surgeons were limited to using skin grafts from a patient’s own unburned skin. Most often, this skin came from the patient’s scalp, the area least likely to be burned. However, because skin grafts (and even cadavers) cannot fully replace lost skin, nor are they able to prevent viruses or bacteria from forming, artificial skin is now presented as the better, more useful alternative.

Importance of Elastin
Monitoring how tropelastin, the molecule that makes up much of the body’s elastic fibers, changes over time have been monumental in the creation of artificial skinThis is because tropelastin accommodates for the flexibility and self-assembly of the skin, as well as the method to confer elasticity on blood vessels, skin and lungs. According to research published in the February 2016 edition of the journal Science Advances,2 this information has been used to predict the behavior and biological performance of newly designed elastin sheets for skin regeneration.artifiical limb

A model hand with artificial mechanoreceptors shakes hands with a human. Photo courtesy Bao research group, Stanford University.

 

The report additionally notes that, when fully developed, these artificial elastin sheets can be used for an array of therapeutic purposes, made lighter to repair skin or denser to repair other forms of tissue. The sheets can also be placed over wounds to assist in healing deep lacerations, or even used to build tubes able to function as substitute arteries.

Elastin used as a synthetic (laboratory-produced) substitute for human skin has additionally helped scientists in Australia to create a product that doubles the speed at which the body can repair itself. Awarded a $1 million grant from global charity Wellcome, a team of researchers from Sydney University has used tropoelastin molded into long fibers, tubes and sponges to repair numerous tissues in the body, ranging from lungs to bones.3

Recreating Nerve Function
Also progressing the capabilities of synthetic skin, engineers with the Bao Research Group at Stanford University have made an impact by integrating an oscillator circuit into a specialized plastic skin-like material that is extremely sensitive to pressure. This electrical device converts the direct current from a power supply to an alternating current. It also allows for flexing, in addition to servings as a sensor for touch to the brain.4

This work, conducted by Stanford’s 17-person research team, makes increasingly possible the delivery of a newfound sense of touch through “skin” to both burn victims and people with prosthetic limbs. Acting in a way that simulates how the human brain encodes information from pressure, the more pressure applied to this material, the higher the electrical spike is generated, and therefore a stronger sensation is felt.5

The circuit integration, developed by Xerox, can be used to convert electrical signals detected by the sensor into signals that the brain can comprehend. This technology is what has allowed Stanford’s project to be able to print flexible circuits evenly across a large area, mimicking the nerve pathways in the skin.

SEE ALSO: Critical Burn Care

“The skin is made of several different materials that provide different functions. The main aspect of skin that we are trying to mimic is the way in which the device produces electrical signals,” explained researcher Alex Chortos, a doctoral candidate at Stanford University, in California who is leading the effort. “Information about stimuli in skin is encoded as the time between voltage pulses. We developed a device that mimics these biological receptors by coupling a pressure sensor with a flexible plastic circuit. The flexible circuit produces voltage pulses and the time between the pulses is determined by the pressure on the sensor.

The Next Steps
Chortos further explained that, since the mechanoreceptor outputs information that is encoded in the same way as real mechanoreceptors, his team expects that this technology will simplify the process of integrating touch information with the human neurological system. His team also expects to eventually be able to directly interface the sensors with nerves. As neural interfaces improve, these sensors could be used to produce prosthetic skin that is tough, durable, low-cost and feels more like real skin

Yet in order for this device to effectively work it will need to be able to stimulate nerves electrically, allowing the product to be applicable to real prosthetic devices. If this were the case, the artificial skin produced by Chortos and Benjamin Tee would have the potential to forever change the lives of burn victims and amputees.

Lindsey Nolen is a former ADVANCE staff writer.

References

1. Slate. The Virtue of Failed Experiments. http://goo.gl/r8XbDh

2. Science Advances. Subtle balance of tropoelastin molecular shape and flexibility regulates dynamics and hierarchical assembly.
http://goo.gl/pdCDps

3. Yahoo! News. Synthetic skin could help repair wounds twice as fast: study. https://goo.gl/ICH944

4. Standford News. Stanford engineers create artificial skin that can send pressure sensation to brain cell. http://goo.gl/7fg5vL

5. ABC 7 News. Stanford Researchers Create Artificial Skin That Senses Touch. http://goo.gl/LF2ns6

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