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RESEARCH ARTICLE

Recombinant Human Collagen-Based Bioinks for

the 3D Bioprinting of Full-thickness Human Skin

Equivalent

Yang Yang 1,2,3† , Runze Xu 1,2,3† , Chengjin Wang 1,2,3 , Yuzhi Guo 1,2,3 , Wei Sun 1,2,3,4 *, Liliang Ouyang 1,2,3 *

1 Department of Mechanical Engineering, Tsinghua University, Beijing 100084, China
2 Biomanufacturing and Rapid Forming Technology Key Laboratory of Beijing, Tsinghua University, Beijing 100084, China
3 Biomanufacturing and Engineering Living Systems – Innovation International Talents Base (111 Base), Tsinghua
University, Beijing 100084, China
4 Department of Mechanical Engineering and Mechanics, Drexel University, Philadelphia, PA 19104, USA
† These authors contribute equally to this work

Abstract: As a major extracellular matrix component within the skin, collagen has been widely used to engineer human
skin tissues. However, most collagen is extracted from animals. Here, we introduced recombinant human type III collagen
(rhCol3) as a bioactive component to formulate bioinks for the bioprinting of a full-thickness human skin equivalent. Human
dermal fibroblasts were encapsulated in the gelatin methacryloyl-rhCol3 composite bioinks and printed on a transwell to
form the dermis layer, on which human epidermal keratinocytes were seeded to perform an air-liquid interface culture for
6 weeks. After optimizing the bioink formulation and bioprinting process, we investigated the effect of rhCol3 on skin tissue
formation. The results suggest that a higher concentration of rhCol3 would enhance the growth of both cells, resulting in a
more confluent (~100%) spreading of the epidermal keratinocytes at an early stage (3 days), compared to the rhCol3-free
counterpart. Moreover, in an in vivo experiment, adding rhCol3 in the hydrogel formulation would contribute to the skin
wound healing process. Taken together, we conclude that rhCol3 could act as a functional bioink component to promote basic
skin cellular processes for skin tissue engineering.
Keywords: Recombinant human collagen; Skin constructs; 3D printing; Bioinks

*Correspondence to: Liliang Ouyang, Department of Mechanical Engineering, Tsinghua University, Beijing 100084, China; ouy@tsinghua.edu.
cn; Wei Sun, Department of Mechanical Engineering, Tsinghua University, Beijing 100084, China; weisun@tsinghua.edu.cn
Received: May 6, 2022; Accepted: June 5, 2022; Published Online: August 25, 2022
(This article belongs to the Special Issue: Composite/Multi-component Biomaterial Inks and Bioinks)

Citation: Yang Y, Xu R, Wang C, et al., 2022. Recombinant Human Collagen-Based Bioinks for the 3D Bioprinting of Full-thickness Human
Skin Equivalent. Int J Bioprint, 8(4): 611. Doi: http://doi.org/10.18063/ijb.v8i4.611

1. Introduction with epidermal keratinocytes through biochemical cues
(e.g., keratinocytes growth factor) and hence regulate
Skin is the largest organ of the human body that functions [3]
as a physical barrier to protect inner organs from physical epidermis growth .
contact, toxins, pathogens, and loss of heat and water . The skin extracellular matrix (ECM) is an another
[1]
The skin tissue is composed of the epidermis and its significant part of the skin stem cell niche that supports
underlying dermis. The maintenance of the epidermis the adhesion, migration, proliferation, and differentiation
integrity is regulated through a balance between of skin cells, which are fundamental cellular processes for
[4]
proliferation and differentiation of the residing epidermal skin tissue development and regeneration . Type I and
cells, mostly epidermal keratinocytes . The dermis, type III collagens are the major structural constituents of
[2]
primarily composed of dermal fibroblasts, could interact ECM in native skin . Particularly, type III collagen was
[5]
© 2022 Author(s). This is an Open-Access article distributed under the terms of the Creative Commons Attribution License, permitting distribution and
reproduction in any medium, provided the original work is properly cited.
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