Skin!

December 20th, 2014| Topic: RaMbLeS | 0

Prosthetics has come a long way. You have prostheses for the face both inside and outside the mouth, prostheses of the neck including substitutes for the larynx, prostheses for limbs both upper and lower and to fit a variety of limb losses or amputations, and prostheses for other body parts.

And some have been around for a long time. Herodotus, the 5th-century BC Greek historian, mentions a guy named Hegesistratus who had a prosthetic foot. Of course, there’s the Olympic athlete Oscar Pistorius of our own time, who lost both his legs below the knees as an infant, fitted with blade-like artificial limbs.

These prostheses are becoming increasingly sophisticated, some even controllable by the patient’s mind. But one struggle with all these prostheses has been the development of artificial skin that can function and feel like the real thing. Until now …

“Stretchable Silicon Nanoribbon Electronics for Skin Prosthesis,” published recently in Nature Communications, details the work of researchers from South Korea and the US who designed “smart skin,” that can feel humidity or even a firm handshake.

Thus far, research on skin in prosthetics had focused on the aesthetic factor; now the thrust is on increased function—natural function.

The Korean-US collaboration’s skin looks like a see-through glove draping a prosthetic hand, and it is made of a soft polymer—“elastomer”—that contains an array of platinum gauges and sensors and electrodes that stimulate existing nerves. This remarkable organ—yup! the skin is the largest organ of the body, all 5.5 lbs of it on an average human—can discriminate between wet and dry and between cold and hot. It can accomplish complex operations—shaking hands, tapping keyboards, catching baseballs, etc. Heating devices on this artificial skin also make it warm to the touch, almost like normal skin, elastic and soft.

Said Kim Dae-Hyeong, one of the co-authors on the study:

Previously, these robots or prosthetic arms/legs did not have skins that enable high resolution/sensitivity sensing of pressure, strain, temperature, humidity. We focused on this point by developing high density/sensitivity sensor array that is similar with the real human skin.”

Many of the improvements owe their success to fancy sensors made of silicon ribbons that are flexible and can stretch: they are both sensitive and have a wider dynamic range capable of responding to a vast range of data. Of course, it will take a while to duplicate the 12 feet of nerves, 3 feet of blood vessels, 10 hair follicles, 100 sweat glands, and hundreds of nerve endings that are found in each square centimeter of real human skin.

One marvels at the creation of God!

Did You not … clothe me with skin and flesh ….
Job 10:10–11

And what’s more, God sent his Son to earth with skin!

Sending His own Son in the likeness of sinful flesh and as an offering for sin …
Romans 8:3

Yes, God took on flesh … and skin! (And nails, and toes, and hair, and a pancreas, and ears, ….) Jesus Christ, God Incarnate, …

… who, although He existed in the form of God, … emptied Himself,
taking the form of a bond-servant,
and being made in the likeness of men.
Philippians 2:6–7

And so the Nicene Creed of the third century declares:

We believe … in the one Lord Jesus Christ, … who for us men, and for our salvation, came down and was incarnate and was made man.”

Veiled in flesh the Godhead see;
Hail th’incarnate Deity,
Pleased as man with man to dwell,
Jesus, our Emmanuel.
Charles Wesley, 1739

Have a blessed Christmas!