By April Garbuz, Wilton High School
I had the pleasure of speaking with Dr. John Rogers about his recent work in creating electronics that mimic the physical structure of skin. These epidermal electronic are applied to the body like a temporary tattoo. The medical possibilities for this non-invasive technology are seemingly limitless. Dr. Rogers, professor of materials science and engineering and professor of chemistry at University of Illinois, told us all about it.
How did you come up with the concept of epidermal electronics?
We’ve been interested in figuring out new ways to integrate electronics, in an intimate and seamless fashion with the human body. We started with the heart and brain, in the form of advanced surgical tools, and then more recently moved to the skin. Skin is interesting because it is the largest organ and our primary sensory mode of interaction; it also forms a very natural location to non-invasively integrate electronics with the body. Temporary tattoos provide a vision for what we wanted to accomplish, because they are removable and do not irritate skin or restrict motion. Electronics in that format would be ideal.
What were your goals when working on the design?
[My goal was to] create a form of electronics that has physical properties similar to skin -- particularly, elastic moduli, bending rigidities, and thicknesses designed to match the upper layer of the skin, the epidermis. The goal was to transform conventional, rigid integrated circuits into forms that are soft and elastic, just like biological tissues. In this form, electronics can integrate in a very natural way, both mechanically and electrically.
What is the electronic skin made of?
It is a hybrid system of extremely thin silicon, structured into filamentary serpentine shapes with devices built in that kind of geometry. Those devices are interconnected with wires that have the same shape in an open mesh format, similar to a spider web. That kind of a system bonded to a thin sheet of rubber-like material, such as silicon, creates a circuit that mimics the physical properties of skin.
Has this invention been attempted before?
People have been interested in flexible electronics, but nothing has been demonstrated with the type of mechanics that we were able to achieve. Traditional silicon integrated circuits are built on the surface of silicon wafers that have similar properties to glass. They are flat, brittle, rigid, and -- if you drop them -- they will break. That material is far removed, mechanically, from the soft elasticity of skin.
What proved to be the most challenging part of creating epidermal electronics?
It was challenging to manage the mechanics of brittle materials with the elastic properties we needed to mimic skin. We conducted systematic studies, both experimental and computational, to ensure the circuits could interact intimately with the skin.
How can this technology be applied in the medical field?
The nearest term opportunities are to use the epidermal electronics for physiological status monitoring. Current technologies have rigid point contact electrodes you tape onto the skin and bulk wires that connect to a separate box of rigid electronics. That works in certain clinical and research settings, but it’s uncomfortable, irritating to the skin, constrains motion, and the number of electrode interfaces you can have is limited by the bulk wiring. Our approach brings all of the electronics and a multitude of electrodes into contact with the skin in a very noninvasive, natural way, which is mechanically invisible to the person who is wearing the device because it’s not constraining the motion of the skin at all. In more advanced stimulation applications, the human-machine interface could measure processes in the body, and then react to those stimulations. The electronics could even assist with rehabilitation.
Check out this video of the electronics being applied like a temporary tattoo!
Dr. Rogers was on Science Friday earlier this month talking about his skin-like circuit. You can listen in the player below.
Electronic 'Skin' Monitors Brain, Heart Activity