Replacement of skin has been one of the most challenging aims for surgeons ever since the introduction of skin grafts in 1871. It took more than one century until the breakthrough of Rheinwald and Green in 1975 that opened new possibilities of skin replacement. The combination of cell culture and polymer chemistry finally led to the field of tissue engineering. Many researchers all over the world have been fascinated by the chance of creating a skin-like substitute ex vivo without any further harm to the patients, especially those with massive burns. Many different approaches to
Many researchers all over the world have been fascinated by the chance of creating a skin-like substitute ex vivo without any further harm to the patients, especially those with massive burns. Many different approaches to create new substitutes and further improvements in genetical and stem cell research led to today’s skin equivalents. But still, the “gold standard” for wound coverage is the autologous split-thickness skin graft. Future research will aim at originating biologically and physiologically equal skin substitutes for the treatment of severe burns and chronic ulcers.
A group of Korean and U.S. researchers have now developed a polymer designed to mimic the elastic and high-resolution sensory capabilities of real skin.
The polymer is infused with dense networks of sensors made of ultrathin gold and silicon. The normally brittle silicon is configured in serpentine shapes that can elongate to allow for stretchability.
Another such research in US created artificial skin in a lab that can “feel” similar to the way a fingertip senses pressure, and could one day let people feel sensation in their prosthetic limbs, researchers say.
The researchers were able to send the touching sensation as an electric pulse to the relevant “touch” brain cells in mice, the researchers noted in their new study.
The stretchy, flexible skin is made of a synthetic rubber that has been designed, to have micron-scale pyramid like structures that make it especially sensitive to pressure, sort of like mini internal mattress springs. The scientists sprinkled the pressure-sensitive rubber with carbon nanotubes— microscopic cylinders of carbon that are highly conductive to electricity — so that, when the material was touched, a series of pulses is generated from the sensor.
Similarly, Stanford engineers have created a plastic “skin” that can detect how hard it is being pressed and generate an electric signal to deliver this sensory input directly to a living brain cell.
Zhenan Bao, a professor of chemical engineering at Stanford, has spent a decade trying to develop a material that mimics skin’s ability to flex and heal, while also serving as the sensor net that sends touch, temperature and pain signals to the brain. Ultimately she wants to create a flexible electronic fabric embedded with sensors that could cover a prosthetic limb and replicate some of skin’s sensory functions.
The heart of the technique is a two-ply plastic construct: the top layer creates a sensing mechanism and the bottom layer acts as the circuit to transport electrical signals and translate them into biochemical stimuli compatible with nerve cells. The top layer in the new work featured a sensor that can detect pressure over the same range as human skin, from a light finger tap to a firm handshake.