Simple and robust 3D bioprinting of full-thickness human skin tissue

Abstract

Artificial skins have been used as skin substitutes for wound healing in the clinic, and as in vitro models for safety assessment in cosmetic and pharmaceutical industries. The three-dimensional (3D) bioprinting technique provides a promising strategy in the fabrication of artificial skins. Despite the technological advances, many challenges remain to be conquered, such as the complicated preparation conditions for bio-printed skin and the unavailability of stability and robustness of skin bioprinting. Here, we formulated a novel bio-ink composed of gelatin, sodium alginate and fibrinogen. By optimizing the ratio of components in the bio-ink, the design of the 3D model and the printing conditions, a fibroblasts-containing dermal layer construct was firstly fabricated, on the top of which laminin and keratinocytes were sequentially placed. Through air-liquid interface (ALI) culture by virtue of sterile wire mesh, a full-thickness skin tissue was thus prepared. HE and immunofluorescence staining showed that the bio-printed skin was not only morphologically representative of the human skin, but also expressed the specific markers related to epidermal differentiation and stratum corneum formation. The presented easy and robust preparation of full-thickness skin constructs provides a powerful tool for the establishment of artificial skins, holding critical academic significance and application value.

Full Skin Equivalent Models for Simulation of Burn Wound Healing, Exploring Skin Regeneration and Cytokine Response

“…Studies usually culture organotypic skin models up to 3 weeks [ 37 , 38 , 39 , 40 ], but in light of preclinical studies, culture times longer than 3 weeks could be required. In the development of 3D models, predominantly the histology, composition of the extracellular matrix, or cell survival is studied [ 41 , 42 ]. Our study not only showed that the FSEs were capable of forming a functional epidermis, but also showed that these models were able to regenerate after thermal injury.…”

Progress in Gelatin as Biomaterial for Tissue Engineering

“…As this natural polymer provides a suitable environment for cell growth, inks composed of such material have been employed to design several tissue-like systems or models (tumor, skin, muscle) [112][113][114]. A noteworthy example developed a heterogeneous tumor system based on a composite ink consisting of gelatin, alginate and cellulose.…”

3D Bioprinting in Tissue and Organ Regeneration

“…The majority of the top layer of the epidermis is composed of keratinocytes organised into the keratinised stratified squamous epithelium [33]. This basement membrane also separates the epidermis from the dermis [62]. In the stratum corneum, proliferative cells undergo differentiation sequentially, with newly undifferentiated cells at the bottom and terminally differentiated cells at the surface [11].…”

“…The papillary area is rich in type III collagen, whereas the reticular region has more type I collagen [63]. This variation in the ratio of collagen in the extracellular matrix of the dermis is responsible for the skin's elasticity and mechanical strength [62]. Due to the numerous cell types, it contains, including vasculature, neurons, and hair follicles, the dermis links the rest of the body and the skin [62,63].…”