3D skin models along with skin-on-a-chip systems:A critical review

Skin is the largest organ in human body,and it plays an important role in regulating physiological microenvironments and acts as a barrier to protect human body from harmful intrusions.The demand for fully functional skin models(also called skin equivalents,SE)in an in-vivo mimicking culturing microenvironment has been increased dramatically due to the fast development in skin disease treatments and skin care products.Owing to the emerging of the concept and technology of organ-on-chips along with the three-dimensional(3D)bioprinting technology,3D skin models and their applications have been fast evolving.In this paper,the advances in the development of 3D skin models along with skin-on-a-chip(SOC)are reviewed and commented.One of the findings with this paper is that the SOC together with the 3D bioprinting technology is promising to construct fully functional 3D skin models in the field of pharmaceutical and cosmetic industries.

Landscape dynamic network biomarker analysis reveals the tipping point of transcriptome reprogramming to prevent skin photodamage

Skin,as the outmost layer of human body,is frequently exposed to environmental stressors including pollutants and ultraviolet(UV),which could lead to skin disorders.Generally,skin response process to ultraviolet B(UVB)irradiation is a nonlinear dynamic process,with unknown underlying molecular mechanism of critical transition.Here,the landscape dynamic network biomarker(lDNB)analysis of time series transcriptome data on 3D skin model was conducted to reveal the complicated process of skin response to UV irradiation at both molecular and network levels.The advanced l-DNB analysis approach showed that:(i)there was a tipping point before critical transition state during pigmentation process,validated by 3D skin model;(ii)13 core DNB genes were identified to detect the tipping point as a network biomarker,supported by computational assessment;(iii)core DNB genes such as COL7A1 and CTNNB1 can effectively predict skin lightening,validated by independent human skin data.Overall,this study provides new insights for skin response to repetitive UVB irradiation,including dynamic pathway pattern,biphasic response,and DNBs for skin lightening change,and enables us to further understand the skin resilience process after external stress.