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While the detrimental health effects of prolonged ultraviolet (UV) irradiation on skin health have been widely accepted, the biomechanical process by which photoaging occurs and the relative effects of irradiation with different UV ranges on skin biomechanics have remained relatively unexplored. In this study, the effects of UV-induced photoageing are explored by quantifying the changes in the mechanical properties of full-thickness human skin irradiated with UVA and UVB light for incident dosages up to 1600 J/cm2. Mechanical testing of skin samples excised parallel and perpendicular to the predominant collagen fiber orientation show a rise in the fractional relative difference of elastic modulus, fracture stress, and toughness with increased UV irradiation. These changes become significant with UVA incident dosages of 1200 J/cm^2 for samples excised both parallel and perpendicular to the dominant collagen fiber orientation. However, while mechanical changes occur in samples aligned with the collagen orientation at UVB dosages of 1200 J/cm^2, statistical differences in samples perpendicular to the collagen orientation emerge only for UVB dosages of 1600 J/cm^2. No notable or consistent trend is observed for the fracture strain. Analyses of toughness changes with maximum absorbed dosage reveals that no one UV range is more impactful in inducing mechanical property changes, but rather these changes scale with maximum absorbed energy. Evaluation of the structural characteristics of collagen further reveals an increase in collagen fiber bundle density with UV irradiation, but not collagen tortuosity, potentially linking mechanical changes to altered microstructure. 

The field of soft wearable bioelectronics requires materials that are flexible, stretchable, biocompatible, and capable of being used over long durations. Although polydimethylsiloxane (PDMS) is one of the most commonly used substrates for these devices due to its biomimetic properties compared to biological tissues, its intrinsic hydrophobicity causes it to underperform in biological environments. In this work, a hydrophilic, stretchable PDMS electrospun fibrous mat is developed to overcome this limitation by incorporating the amphiphilic polymer polyethylene glycol block copolymer (PEG‐BCP) into the porous PDMS matrix. The nonwoven hydrophilic silicone mat shows apparent improvement in stable hydrophilicity, indicated by a significant decrease in water contact angle (from 125° to 51°) for 7 days, along with improved cellular adhesion and enhanced breathability. The PDMS‐PEG fibers show higher cell proliferation than unmodified PDMS fibers, suggesting potential for long‐term biological applications. The fibrous mat also maintains its structural integrity under mechanical stress, demonstrated by a stretchability of up to 308.8% strain with reduced adhesion forces. This novel material surpasses previous PDMS fibrous substrates and enables electroless gold plating, providing a promising future for wearable fibrous electronics and biomedical devices featuring hydrophilic, stretchable, conductive, and biointegrated materials.