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International Journal of Bioprinting Bioprinted organ-on-a-chip with biomaterials

role in unraveling the complexities of the human body. For the fabrication of an in vitro model, it is imperative
Accordingly, this review highlights examples of organs- to mimic the multilayer structure of the skin. Several
on-a-chip that successfully mimic skin, blood vessels, and models reflecting this aspect have been developed over
kidneys, shedding light on their biological implications. the years. An in vitro skin model comprising dermal and
Moreover, a detailed exploration of disease-on-a-chip epidermal layers was developed in the 1980s, primarily
replicating organ-specific diseases is presented. To aiding research in the medical treatment of skin. Widely
99
provide a comprehensive overview, Table 3 summarizes adopted in clinical dermatology and wound healing
these examples. studies, this model has also proven to be a valuable
3.1. Skin alternative to animal experiments in the development
100
The skin, constituting the largest part of the human body, of cosmetics and pharmaceuticals. Efforts to precisely
serves as a vital barrier that separates internal and external mimic human skin have led to studies integrating various
body parts, safeguarding it from environmental factors. cells, multilayer structures, and appendages within a
The human skin comprises the epidermis and dermis. The single platform. 101,102 Recent advancements include the
epidermis acts as a barrier to protect the internal organs establishment of blood vessel channels within an in vitro
103
from external contaminants and provides waterproofing. skin model, serving application in angiogenesis research
90
It is primarily composed of keratinocytes. In contrast, and disease models. Moreover, active attempts have been
the dermis functions to position skin appendages and is made to establish connections with other organs using
a vascularized structure primarily comprising fibroblasts 3D bioprinting. 85,104 Unlike conventional manufacturing
that refine the ECM. 95-98 methods, 3D bioprinting enables precise layer-by-layer

Table 3. Various organs-on-a-chip
Target organ Biomaterials Cell type Printing method Main outcome Reference
Skin Collagen Murine fibroblasts (NIH- Laser-assisted bio- First multicellular 3D structure 85
3T3), human keratinocyte printing of skin using laser-assisted
(HaCaT) bioprinting
Skin Skin dECM, adipose Human dermal fibroblast, hu- Extrusion-based Creation of the vascularized 90
dECM, vascular dECM man epidermal keratinocyte, bioprinting skin model and application to
human subcutaneous pread- diabetes for the first time
ipocyte, human endothelial
cell (HUVEC)
Vasculature Gelatin HUVEC Stereolithography Development of new bioprint- 91
methacrylate (GelMA) ing technology to create a
double-ring structure
Vasculature Vascular dECM HUVEC, human smooth Extrusion-based Fabrication of the three-layer 92
muscle cell (HSMC) bioprinting structure of the artery using
triple-coaxial printing and
application to atherosclerosis for
the first time
Kidney Gelatin-fibrin extracel- Human renal proximal tubu- Extrusion-based Dual-channel fabrication of 93
lular matrix hydrogel lar epithelial cell (HRPTEC), bioprinting endothelialization and epithe-
human primary glomerular lialization; mimicking kidney
microvascular endothelial cell filtration function
(GMEC)
Kidney Kidney dECM, alginate Human bone marrow mesen- Extrusion-based Provides optimal simulation 94
chymal stem cell, HRPTEC, bioprinting of glomerular/proximal tubule
HUVEC cross-sections with dual chan-
nels via coaxial printing
Liver Liver dECM, gelatin Primary human hepatocyte, Extrusion-based Creation of 3D sinusoidal struc- 27
human stellate cell, HUVEC bioprinting ture using various primary liver
cells and application to fibrosis
Placenta GelMA, fibronectin Human mesenchymal stem Extrusion-based The first production of a multi- 157
cell, trophoblast bioprinting layer placenta model using 3D
bioprinting
Abbreviation: dECM: decellularized extracellular matrix.

Volume 10 Issue 1 (2024) 28 https://doi.org/10.36922/ijb.1972