Optical Behavior of Human Skin Substitutes: Absorbance in the 200–400 nm UV Range

Abstract

The most recent generation of bioengineered human skin allows for the efficient treatment of patients with severe skin defects. Despite UV sunlight can seriously affect human skin, the optical behavior in the UV range of skin models is still unexplored. In the present study, absorbance and transmittance of the UGRSKIN bioartificial skin substitute generated with human skin cells combined with fibrin-agarose biomaterials were evaluated for: UV-C (200–280 nm), -B (280–315 nm), and -A (315–400 nm) spectral range after 7, 14, 21 and 28 days of ex vivo development. The epidermis of the bioartificial skin substitute was able to mature and differentiate in a time-dependent manner, expressing relevant molecules able to absorb most of the incoming UV radiation. Absorbance spectral behavior of the skin substitutes showed similar patterns to control native skin (VAF > 99.4%), with values 0.85–0.90 times lower than control values at 7 and 14- days and 1.05–1.10 times the control values at 21- and 28-days. UV absorbance increased, and UV transmission decreased with culture time, and comparable results to the control were found at 21 and 28 days. These findings support the use of samples corresponding to 21 or 28 days of development for clinical purposes due to their higher histological similarities with native skin, but also because of their absorbance of UV radiation.

Histological assessment of nanostructured fibrin‐agarose skin substitutes grafted in burnt patients. A time‐course study

“…Bioartificial tissues based on fibrin‐agarose biomaterials displayed an elastic behavior and its modulus of Young was comparable to native tissues, 11 and our previous time‐course analysis carried out for 4 weeks demonstrated that these properties remained stable upon the time in culture 9 . In addition, the optical characterization UGRSKIN model showed that the epidermal layer was able to mature and differentiate being able to absorb most of the incoming UV light, as it is the case of the native skin 10 . When grafted in vivo on immune‐deficient animal models, UGRSKIN demonstrated to be highly biocompatible and able to contribute to skin regeneration 8 .…”

“…This skin model was characterized ex vivo and in vivo in laboratory animals using several histological, histochemical, immunohistochemical, and other analysis methods able to demonstrate that the model was safe and efficient. [8][9][10] In fact, our preclinical studies demonstrated that the biochemical properties and histological structure of the UGRSKIN skin model were similar to the native human skin at both, the epidermal and the dermal layers. Ex vivo, UGRSKIN showed to be biomechanically comparable to the native human skin, with adequate properties as determined by compressive and shear tests.…”

“…In this regard, we developed a bioartificial model of human skin called UGRSKIN or NANOGSKIN, which combines highly biocompatible fibrin‐agarose biomaterials containing human dermal fibroblasts with human skin keratinocytes able to form a stratified epithelial layer on top. This skin model was characterized ex vivo and in vivo in laboratory animals using several histological, histochemical, immunohistochemical, and other analysis methods able to demonstrate that the model was safe and efficient 8–10 . In fact, our preclinical studies demonstrated that the biochemical properties and histological structure of the UGRSKIN skin model were similar to the native human skin at both, the epidermal and the dermal layers.…”

“…9 In addition, the optical characterization UGRSKIN model showed that the epidermal layer was able to mature and differentiate being able to absorb most of the incoming UV light, as it is the case of the native skin. 10 When grafted in vivo on immune-deficient animal models, UGRSKIN demonstrated to be highly biocompatible and able to contribute to skin regeneration. 8 One of our main findings was that the bioartificial skin substitute was able to remodel its structure and composition in a time-dependent manner, with a progressive process of extracellular matrix (ECM) remodeling and biosynthesis of crucial fibrillar and non-fibrillar components along with cell differentiation and maturation.…”

Histological characterization of the human masticatory oral mucosa. A histochemical and immunohistochemical study

“…Quantitative analyzes were performed using ImageJ software (version 1.53 k, National Institute of Health, Bethesda, MD) and following standardized protocols previously described (Carriel et al, 2014; Ortiz‐Arrabal et al, 2021; Rodriguez‐Pozo et al, 2020; Ruiz‐López et al, 2022; Chato‐Astrain et al, 2023; Ortiz‐Arrabal et al, 2023). Briefly, the histomorphological features of the POM and OOM was assessed measuring epithelial length, thickness, and cell area, as well as rete ridge/papillae dimensions.…”