Age-related mechanical properties of human skin: An in vivo study

Abstract

We have investigated in vivo how various viscoelastic parameters that describe the mechanical properties of the human skin may vary with age. Accordingly, we have used a mechanical device that records the torsional extensibility of the skin. When submitted to a low torque, the time-response curve of the skin affords the determination of the immediate extensibility (UE), the immediate recovery (UR), the viscoelastic part of the deformation (UV), the elastic recovery (UR/UE), and the creep relaxation time (tau). Because the skin thickness varies with age and primarily governs the mechanical properties, it was measured through an ultrasound technique at the same sites (forearm) where the torque was applied. The results show that the skin maintains its thickness and extensibility up to the seventh decade as opposed to its elasticity or recovery capacities, which decrease from an early age. The viscous part of the deformation is constant through life, whereas the creep relaxation time decreases linearily with age. Except for skin thickness, no differences in these parameters between men and women were detected. The significance of these results are discussed in terms of structure alterations. The determination of the elastic recovery (UR/UE) appears to be a parameter of choice for illustrating skin aging.

A micromechanical comparison of human and porcine skin before and after preservation by freezing for medical device development

“…The E FT, which was similar in magnitude to previously published results73233, was not significantly influenced by skin type, state, or RH. A strong statistical significance was observed for the interaction between skin source and state on the E FT ( P  < 0.0001).…”

Mechanical response of human female breast skin under uniaxial stretching

“…Such mechanical tests help to develop an understanding of the normal functional response of this organ and predict its response in cases of medical interventions such as surgery. Many experiments have been performed on skin to understand its complex mechanical behavior [see for example, porcine: Shergold et al, 2006 and Khatam et al, 2014; murine: Munoz et al, 2008; human: Abas and Barbenel, 1982, Dunn and Silver, 1983, Escoffier et al, 1989, Clark et al, 1996, Reihsner and Menzel, 1996, Bischoff et al, 2000, Silver et al, 2001, Hendriks et al, 2003, Kvistedal and Nielsen, 2009, Annaidh et al, 2012, and Tonge et al, 2013; and rabbit: Lanir and Fung, 1974]. Although it is generally accepted that uniaxial tension tests are insufficient to characterize skin completely, such tests are still typically performed on skin specimens in vitro (see for example, Moronkeji and Akhtar, 2015).…”

“…Although it is generally accepted that uniaxial tension tests are insufficient to characterize skin completely, such tests are still typically performed on skin specimens in vitro (see for example, Moronkeji and Akhtar, 2015). There are numerous in vivo tests on skin as well since this will provide important characterization under physiologically correct conditions (see for example, Abas and Barbenel, 1982; Manschott and Brakkee, 1986; Escoffier et al 1989, Kvistedal et al, 2009). …”

Mechanics of fragmentation of crocodile skin and other thin films

“…Flexible skins of other animals, such as mammal and bird, are hard to reach a stable fragmentation pattern in the skin under normal state. However, there are extreme conditions18, for example dehydration, oldness and illness19202122, which can alter the mechanics of the skin and make the stable fragmentation possible. From a different angle of view, the skin fragmentation of crocodile can be attributed to mechanical adaption23.…”