This elasticity comes from the skin’s mechanical properties, including thickness and internal structure. Skin contains a network of microscopic fibres, mainly made from collagen and elastin. Collagen gives skin its strength and structure, while elastin allows for stretch and recoil. Skin is made up of three main layers, each with its own role. The outer protective layer (epidermis), varies in pigmentation. Dermis, the middle layer, contains connective tissue, hair follicles and blood vessels, responsible for strength and support. Subcutis, the deepest layer, provides insulation and protection against shock. Together, these layers give skin both its mechanical strength and flexibility.
“Skin might feel soft when you touch it, but mechanically it’s incredibly sophisticated,” says Fay Claybrook, a researcher in the Engineering Organ Support Technologies group at the University of Twente. “The way the layers work together to stretch and recover is something engineers still struggle to mimic.”
Why does skin change over time?
Skin is the most elastic during childhood and early adulthood. As we age, collagen production decreases, and elastin fibres begin to break down. The skin becomes thinner, and recovery after stretching takes longer. This is a normal part of ageing, but it can also be accelerated by factors such as smoking, dehydration and rapid weight change. Loss of elasticity is what causes wrinkling and sagging and, ultimately, slower recovery from deformation.
You can even feel this change yourself. A simple way to get a rough idea of your skin’s elasticity is the pinch test. Gently pinch the skin on the back of your hand, lift it slightly, hold for two seconds and then let go. If the skin has high elasticity, it returns to its normal position almost immediately, within one or two seconds. If it takes longer and stays raised for a short time, the elasticity is lower. However, this is only a general indication, and factors like hydration and temperature can influence the result, but it gives a useful sense of how well your skin recovers after deformation.
Although we often associate skin elasticity with appearance, think of wrinkles. But it is essential for protecting the body. Elastic skin helps absorb mechanical forces, accommodates movement and reduces the risk of tears or damage during daily activities. It also affects how the skin responds to medical procedures, including pressure and contact from tools or instruments.
Can you make artificial skin behave like the real thing?
In medical and engineering research, realistic artificial skin is essential. Students, researchers and medical professionals need to feel how real skin reacts when it’s pressed, stretched or punctured. But accurately reproducing skin elasticity is harder than it sounds. Most artificial skin-like materials are too stiff, too soft or respond to forces in an unrealistic way.
Real skin is layered and structured, while many simulators rely on a single slab of silicone. However, the materials used in simulators do not need to be safe for the human body, which allows us to focus on achieving realistic mechanical and tactile behaviour of real human tissue through the use of hyperelastic polymers.
Functional realistic artificial skin
At the University of Twente, researchers in the Engineering Organ Support Technologies group and the Cardiac Surgery Innovations Lab (CSIL), focus on creating realistic artificial skin, veins, and arteries that behave mechanically like real human tissue. Instead of copying the skin’s appearance, they focus on its mechanical behaviour. By using designed polymers and layered structures, we can create materials that can be pressed, stretched and compressed like real skin, not only at the surface but also internally. “Our goal isn’t perfect imitation,” Fay says, “but functional realism. We want to bridge the gap between lab models and real human tissue so trainees can learn with confidence.”
By mimicking the fibre networks and layered structures of human skin, we can improve the level of realism for medical training. This improves the training experience for medical professionals. They can practice procedures with more accurate anatomical, mechanical and tactile interactions between skin and deeper vascular structures. Bringing its behaviour into the lab requires both scientific insight and creative engineering. “Your skin may look simple, but mechanically, it is anything but,” says Fay.
