Ageing affects both the structure and the function of the skin. This results in degradation of physiological functions and biophysical properties of organs and tissues putting an alarming economic and social burden on governments and healthcare services. Any significant alteration of skin’s mechanical properties that could affect its structural integrity and barrier function has the potential to cause health effects. With age, the collagen and elastin fibre networks in the dermis become compacted leading to reduction in dermis thickness. Skin photoaging leads to solar elastosis or disintegration of elastic fibers and accumulation of amorphous, thick ended, fragmented elastic fibers. The skin aging process is not yet fully understood.
KEYWORDS: Collagen, Microscopy, Skin, Acoustics, Atomic force microscopy, Ultrasonics, Signal attenuation, In vitro testing, Diagnostics, Atomic force microscope
Skin aging is a complex process accompanied by alterations in skin structure and function. We have investigated the age-related changes in collagen on dermal collagen’s physical properties. Nanomechanical properties of collagen fibrils studied using atomic force microscope nano-indentation and viscoelasticity of the collagen fibers assessed by the acoustic microscopy was investigated. The increase in Young’s modulus with increased age correlated with the increase in sound speed and attenuation is probably due to a change in the density of the fibrils caused by water retention within the fibrils and cross-linkage between fibrils.
KEYWORDS: Collagen, Microscopy, Skin, Acoustics, Atomic force microscopy, Ultrasonics, Signal attenuation, In vitro testing, Diagnostics, Atomic force microscope
Intense pulsed light (IPL) is a high-intensity treatment for skin disorders and ageing. As this treatment regime is often poorly regulated and inadequately studied, we investigate IPL as a cosmetic device and its effects on dermal collagen components of the skin. Biopsies from the back-neck folds of a 4-week-old, 25 kg large white pig were irradiated with intense pulsed light (IPL) (l= 584 nm) at an increased radiation dose of 40 J/cm2 once, thrice and ten times. Samples were cryo-sectioned (10 μm) and stained with picro sirrus red. Ex-vivo biopsies were assessed with polarized light microscopy (PLM), atomic force microscopy (AFM) and scanning acoustic microscopy. Customized software was used to map the sound speed and attenuation on the ultrasonic images Differences in collagen structure were observed between all three levels of irradiation progressing depth-wise into the epidermis. Ex-vivo porcine tissue demonstrated loss of D-banding and gelatinization with increasing dermal depth with higher intensities. Acoustic microscopy demonstrated a significant decrease in sound speed and attenuation that relates to the number of exposures. Sound speed decreases at much faster rates than attenuation.
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