Innovations in Electronic Skin

A larger aging population and people afflicted by chronic diseases are driving the development of e-skin. Read more in this Frost & Sullivan analysis of what's in the works and what to expect down the road.

Once the stuff of science fiction, electronic skin has become a platform technology: an ultra-thin, flexible, wearable device that combines information and communication technologies with innovative materials, microelectronics and sensors. Health care in particular is expected to benefit from the development of what is known as e-skin, driven by a larger aging population and people afflicted by chronic diseases.

More Comfortable and Self-Healing Monitoring Systems

E-skin’s flexible and stretching characteristics facilitate miniaturized semiconductor components, including antennas, light-emitting diodes, nano-scale drug delivery systems and compact power sources. Sensors that measure strain, stress and temperature can be embedded into the flexible substrate—typically silicone-based materials with cross-linked polymers—and applied to different points on the patient’s body. Flexible displays can be printed onto the e-skin to eliminate the discomfort of wearing bulky external monitoring devices.

E-skin is in a nascent stage, with researchers intending to develop a synthetic skin that can heal itself as natural skin does. The key to this work is using a substrate made of elastic polymers, such as polydimethylsiloxane, that contain highly conductive electrodes, gold nanoparticles and microscopic particles of nickel. When the synthetic tissue is torn, hydrogen bonds in the polymer and the gold nanoparticles will heal the damage with the microscopic nickel particles adding strength.

Another trend is to increase the electrical properties of e-skin’s electrodes by using carbon nanotubes, their planar counterpart graphene, and metallic nanowires to provide high conductivity.

Giving Prostheses the Human Touch

There are four potential health care applications for e-skin: prosthetics that can mimic the sense of touch, monitors for life signs such as respiration rate and temperature, wound care, and drug delivery. Major academic institutions and technology firms are pursuing each.

For example, researchers at Stanford University in California have developed a highly sensitive sensor that can be integrated into an e-skin applied to a prosthetic limb. The Stanford team designed the sensor to detect the lightest pressure—as slight as that of a butterfly alighting on the prosthesis—and quickly transmit it to the limb’s wearer.

Across the Pacific, scientists at the Korea Institute of Machinery and Materials in Daejeon, South Korea, have developed an e-skin for a prosthetic hand. It senses the intensity of force, pressure or stress—and detects its direction—to help a person recognize an object’s shape and texture. 

Healthy Tattoos

Private firms developing e-skin technologies include Chaotic Moon, LLC, of Austin, Texas, whose electronic wearable “tattoos” use heart rate, hydration level and the composition of sweat to determine body temperature and detect stress in the wearer. The devices upload health data using Bluetooth Low Energy or low-frequency mesh networks. The military is interested in the device to monitor soldiers.

With skin cancer the most prevalent form of cancer in the United States, it is a prime market for the My UV Patch marketed by La Roche-Posay, a subsidiary of French cosmetics giant L’Oreal. The flexible, transparent e-skin uses light-sensitive dyes that change color upon exposure to ultraviolet rays. Excessive exposure to UV light contributes to skin cancer. The My UV Patch user scans the wearable device with a smartphone or tablet and tracks UV exposure using a mobile app that is compatible with both Android and iOS operating systems. The My UV Patch app can advise the wearer to apply sunscreen or move into shade. The device was jointly developed by L’Oreal, which licensed the stretchable electronics from MC10 of Lexington, Mass., and PCH International of Cork, Ireland, which produced the UV sensors.

Non-Invasive Wound Tracking

The University of Illinois at Urbana-Champaign is developing an e-skin to replace the tactile and visual methods of monitoring wounds with a non-invasive method. The e-skin uses thermal sensors and actuators to precisely map the temperature and thermal conductivity of the skin near a wound to prevent it from worsening or becoming infected.

Drug Delivery to Help Smokers Kick the Habit

Phase 2 clinical trials show the promise of an e-skin developed by Chrono Therapeutics of Hayward, Calif., to detect when smokers have the strongest desire for a cigarette. The transdermal patch will then deliver nicotine into the wearer’s bloodstream, stopping the craving. That craving that is particularly intense in the morning. Research shows that 75% of smokers light up their first cigarette within 30 minutes of awakening. Chrono differentiates its e-skin patch as being the first nicotine replacement therapy designed to address morning cigarette craving by providing the patient with support before the craving begins. The Chrono patch achieves this by being worn overnight and programmed to the wearer’s wake-up time so it can start delivering nicotine before the wearer awakens.

The Road Ahead

The rise of chronic and non-communicable diseases such as cancer, diabetes and heart disease will drive the need for health monitoring. As the Internet of Things makes home health care a possibility, e-skin will help remotely located clinicians manage chronic diseases and give patients more independence to monitor their own health and wellness. Greater familiarity with technologies used in temporary wearable patches will sharpen the focus on e-skin technologies.

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