Page 50 - IJB-3-2

RESEARCH ARTICLE

Hybrid three-dimensional (3D) bioprinting of retina

equivalent for ocular research

1
1
1*
Pujiang Shi , Tan Yong Sheng Edgar , Wai Yee Yeong and Augustinus Laude 2
1 Singapore Centre for 3D Printing, School of Mechanical and Aerospace Engineering, Nanyang Technological University,
50 Nanyang Avenue Singapore 639798
2 National Healthcare Group Eye Institute, Tan Tock Seng Hospital, Singapore 308433

Abstract: In this article, a hybrid retina construct was created via three-dimensional (3D) bioprinting technology. The
construct was composed of a PCL ultrathin membrane, ARPE-19 cell monolayer and Y79 cell-laden alginate/pluronic
bioink. 3D bioprinting technology was applied herein to deliver the ARPE-19 cells and Y79 cell-laden bioink to ensure
homogeneous ARPE-19 cell seeding; subsequently, two distinctive Y79 cell-seeding patterns were bioprinted on top of the
ARPE-19 cell monolayer. The bioprinted ARPE-19 cells were evaluated by prestoblue assay, F-actin, and hematoxylin/eosin
(HE) staining, and then the cells were observed under laser scanning and invert microscopy for 14 days. The Y79 cells in
alginate/pluronic bioink after bioprinting had been closely monitored for 7 days. Live/dead assay and scanning electrical
microscopy (SEM) were employed to investigate Y79 cell viability and morphology. Both the ARPE-19 and Y79 cells were
in excellent condition, and the successfully bioprinted retina model could be utilized in drug delivery, disease mechanism
and treatment method discoveries.
Keywords: retina, bioprinting, age-related macular degeneration, tissue engineering
*Correspondence to: Wai Yee Yeong, Singapore Centre for 3D Printing, School of Mechanical and Aerospace Engineering, Nanyang
Technological University, 50 Nanyang Avenue Singapore 639798, Singapore; Email: WYYeong@ntu.edu.sg
Received: June 26, 2017; Accepted: July 3, 2017; Published Online: July 10, 2017
Citation: Shi P, Edgar T Y S, Yeong W Y, et al., 2017, Hybrid three-dimensional (3D) bioprinting of retina equivalent for ocular research.
International Journal of Bioprinting, vol.3(2): 138–146. http://dx.doi.org/10.18063/IJB.2017.02.008.
1. Introduction outer retina deterioration, including photoreceptors
and the associated RPE cells. The degeneration leads
he retina is a complex multilayered tissue that to irreversible vision loss, and currently no effective
collects and decrypts information of light energy
Tand then transmits such information to brain to treatments exist to permanently stop the degeneration
reflect images of the visual environment. Retinal pig- and to restore normal retinal function from lost vision.
ment epithelium (RPE) is a highly specialized cell There were some reports regarding retinal regeneration,
monolayer with pigmented microvilli aligning the including application of mature photoreceptors, proge-
Bruch’s membrane located between the neural retina and nitor cells, retinal sheets and RPE cells, and these
[1]
the choroid in the eye . Mature RPE cells are mitotically trials demonstrate improved vision in animal studies.
quiescent under the physiological condition in the eyes; However, the mechanism of the visual improvement
however, the RPE cells start to proliferate when the is not clear, and the data from animal trial cannot be
[1]
neural retina suffers from traumatic injuries . Many translated into effective clinical treatments yet. During
retinal diseases may be linked to RPE degeneration. retinal regeneration, the cell organization/alignment,
The RPE is an essential supporting tissue for nutrient integration and differentiation into retinal cell types
transport, production of growth factors and phagocytosis are critical to its functionality. The photoreceptors/
[2]
of the photoreceptor outer segments . The photoreceptor RPE complex functional unit is vital for normal vision;
and associated retinal circuitry is a complex system, furthermore, their layered organization and correct orien-
and it is challenging to be repaired through regenerative tation are critical for normal function and survival of
medicine [1,2] . the retina. The implanted cells need to complete retinal
Several mechanisms of retina degeneration may cause integration and differentiate into mature retina cell

Hybrid three-dimensional (3D) bioprinting of retina equivalent for ocular research. © 2017 Pujiang Shi, et al. This is an Open Access article distributed
under the terms of the Creative Commons Attribution-NonCommercial 4.0 International License (http://creativecommons.org/licenses/by-nc/4.0/),
permitting all non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
138