Ultraviolet light degrades the mechanical and structural properties of human stratum corneum

Microneedle Arrays for Drug Delivery and Diagnostics: Toward an Optimized Design, Reliable Insertion, and Penetration

“…[134,135] Lapsky and German investigated the impact of varying UV dosage and range on mechanical properties of human SC where, by increasing dosage (up to 4000 J cm −2 ), notable increases in elastic modulus (E), along with decreases in fracture stress, strain, and fracture work were observed. [121] Results also indicated that varying UV types such as, UVA (365 nm), UVB (302 nm), and UVC (265 nm) had no significant effect on skin mechanics, while the amount of absorbed UV energy substantially influenced the SC mechanical properties. For instance, increasing dosage from 10 to 800 J cm −2 , increased the modulus (E) from about 40 to 70 MPa, while work of fracture (W f ) decreased as a function of absorbed dosage (φ) (W f = W 0 e cφ ).…”

“…For instance, human skin characterizations indicate variations of overall skin elastic modulus (E) between 4.5 kPa and 4 MPa, [102] SC elastic modulus (E) variation of 0.6 to 1000 MPa, [70,74] and Poisson ratio (ν) variations between 0.3 and 0.5. [74] These variations are primarily due to the effects of viscoelasticity, [72] anisotropic behavior, [118] skin site, [80,119] age, [93,120] humidity, [44,70,74] species variation (e.g., human skin vs pig skin), [44,112] post processing (e.g., ultraviolet light exposure), [121] ethnicity, [122] gender, [123] test type, and strain rate. [82] Skin behavior can also change over time chronologically and environmentally (e.g., due to UV dose, diet, pollution, atopic dermatitis, and acne), adding more complexity to skin mechanics.…”

The Effects of Ionising and Non-Ionising Electromagnetic Radiation on Extracellular Matrix Proteins

“…Radon gas [11] Diagnostic imaging [12], Radiotherapy [13] Fibrosis [14], Carcinogenesis [15] Non-ionising UVR Sunlight [16] UVR Phototherapy [17] Skin photoageing [18], Vitamin D synthesis [19] Visible light Sunlight [20] Photodynamic therapy [21] Ocular phototoxicity [20] Infrared Sunlight [22] Neural stimulation [22] Skin photoageing [23] Radiowaves Lightning [24] Hyperthermia [25] Brain activity [26] Most investigations into the detrimental side effects of radiation on biological tissues have largely focused on cellular damage, and in particular, the sensitivity of DNA [27,28]. Whilst acute high radiation exposure may kill cells, it has become increasingly clear that lower doses may have sub-lethal effects that are complex, difficult to eliminate and delayed (persisting over long periods of time) [2,7,29,30].…”

“…UVA (365 nm, 1.5 mw/cm 2 ), UV-B (302 nm, 1.6 mw/cm 2 ), UV-C (265 nm, 1.8 mw/cm 2 ), dosage: 10-4000 J/cm 2 Stratum corneum from breast skin tissue extracted [18] Reduced stiffness, fracture stress/strain, at >4000 J/cm 2 UVA and >400 J/cm 2 UVB. The energy required to fracture decreases in a dose-dependent manner.…”

ARTICLE: Alteration to the Skin Barrier Integrity Following Broad-Spectrum UV Exposure in an Ex Vivo Tissue Model

“…[11][12][13] UV exposure was reported to induce epidermal barrier damage by altering the tight junction protein expression, disruption to the basement membrane junctions, decrease in the level of covalently bound ceramides, increase stratum corneum (SC) thickness & increase stratum corneum (SC) thickness and TEWL, and induce degradation to the structural and mechanical integrity of the skin. 11,[13][14][15][16][17][18][19][20][21][22] While each of the studies has furthered the understanding on UV on barrier function, the connection between a physiologically relevant UV dose with the molecular changes to the barrier of the skin remains unclear. This study is the first of two parts that utilized a physiologically relevant, fresh ex vivo skin model to understand how broad-spectrum UV affects the composition of epidermal barrier and illustrate how the application of sunscreen can provide barrier protection.…”