TY - JOUR
T1 - Uniaxial mechanical stretch properties correlated with three-dimensional microstructure of human dermal skin
AU - Zhou, Mengyao
AU - González, Patrick José
AU - van Haasterecht, Ludo
AU - Soylu, Alperen
AU - Mihailovski, Maria
AU - van Zuijlen, Paul
AU - Groot, Marie Louise
N1 - Publisher Copyright: © The Author(s) 2024.
PY - 2024/2/7
Y1 - 2024/2/7
N2 - The intact and healthy skin forms a barrier to the outside world and protects the body from mechanical impact. The skin is a complex structure with unique mechano-elastic properties. To better direct the design of biomimetic materials and induce skin regeneration in wounds with optimal outcome, more insight is required in how the mechano-elastic properties emerge from the skin’s main constituents, collagen and elastin fibers. Here, we employed two-photon excited autofluorescence and second harmonic generation microscopy to characterize collagen and elastin fibers in 3D in 24 human dermis skin samples. Through uniaxial stretching experiments, we derive uni-directional mechanical properties from resultant stress-strain curves, including the initial Young’s modulus, elastic Young’s modulus, maximal stress, and maximal and mid-strain values. The stress-strain curves show a large variation, with an average Young’s modules in the toe and linear regions of 0.1 MPa and 21 MPa. We performed a comprehensive analysis of the correlation between the key mechanical properties with age and with microstructural parameters, e.g., fiber density, thickness, and orientation. Age was found to correlate negatively with Young’s modulus and collagen density. Moreover, real-time monitoring during uniaxial stretching allowed us to observe changes in collagen and elastin alignment. Elastin fibers aligned significantly in both the heel and linear regions, and the collagen bundles engaged and oriented mainly in the linear region. This research advances our understanding of skin biomechanics and yields input for future first principles full modeling of skin tissue.
AB - The intact and healthy skin forms a barrier to the outside world and protects the body from mechanical impact. The skin is a complex structure with unique mechano-elastic properties. To better direct the design of biomimetic materials and induce skin regeneration in wounds with optimal outcome, more insight is required in how the mechano-elastic properties emerge from the skin’s main constituents, collagen and elastin fibers. Here, we employed two-photon excited autofluorescence and second harmonic generation microscopy to characterize collagen and elastin fibers in 3D in 24 human dermis skin samples. Through uniaxial stretching experiments, we derive uni-directional mechanical properties from resultant stress-strain curves, including the initial Young’s modulus, elastic Young’s modulus, maximal stress, and maximal and mid-strain values. The stress-strain curves show a large variation, with an average Young’s modules in the toe and linear regions of 0.1 MPa and 21 MPa. We performed a comprehensive analysis of the correlation between the key mechanical properties with age and with microstructural parameters, e.g., fiber density, thickness, and orientation. Age was found to correlate negatively with Young’s modulus and collagen density. Moreover, real-time monitoring during uniaxial stretching allowed us to observe changes in collagen and elastin alignment. Elastin fibers aligned significantly in both the heel and linear regions, and the collagen bundles engaged and oriented mainly in the linear region. This research advances our understanding of skin biomechanics and yields input for future first principles full modeling of skin tissue.
KW - Collagen fibers
KW - Elastin fibers
KW - Human skin
KW - Mechanical properties
KW - Second harmonic generation
KW - Uniaxial skin stretch
UR - http://www.scopus.com/inward/record.url?scp=85184235046&partnerID=8YFLogxK
UR - https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=85184235046&origin=inward
U2 - 10.1007/s10237-023-01813-3
DO - 10.1007/s10237-023-01813-3
M3 - Article
C2 - 38324073
SN - 1617-7959
JO - Biomechanics and modeling in mechanobiology
JF - Biomechanics and modeling in mechanobiology
ER -