Human Cartilage Tissue Fabrication Using Three-dimensional Inkjet Printing Technology

Summary

The methods described in this paper show how to convert a commercial inkjet printer into a bioprinter with simultaneous UV polymerization. The printer is capable of constructing 3D tissue structure with cells and biomaterials. The study demonstrated here constructed a 3D neocartilage.

Abstract

Bioprinting, which is based on thermal inkjet printing, is one of the most attractive enabling technologies in the field of tissue engineering and regenerative medicine. With digital control cells, scaffolds, and growth factors can be precisely deposited to the desired two-dimensional (2D) and three-dimensional (3D) locations rapidly. Therefore, this technology is an ideal approach to fabricate tissues mimicking their native anatomic structures. In order to engineer cartilage with native zonal organization, extracellular matrix composition (ECM), and mechanical properties, we developed a bioprinting platform using a commercial inkjet printer with simultaneous photopolymerization capable for 3D cartilage tissue engineering. Human chondrocytes suspended in poly(ethylene glycol) diacrylate (PEGDA) were printed for 3D neocartilage construction via layer-by-layer assembly. The printed cells were fixed at their original deposited positions, supported by the surrounding scaffold in simultaneous photopolymerization. The mechanical properties of the printed tissue were similar to the native cartilage. Compared to conventional tissue fabrication, which requires longer UV exposure, the viability of the printed cells with simultaneous photopolymerization was significantly higher. Printed neocartilage demonstrated excellent glycosaminoglycan (GAG) and collagen type II production, which was consistent with gene expression. Therefore, this platform is ideal for accurate cell distribution and arrangement for anatomic tissue engineering.

Introduction

Bioprinting based on thermal inkjet printing is one of the most promising enabling technologies in the field of tissue engineering and regenerative medicine. With digital control and high throughput printheads cells, scaffolds, and growth factors can be precisely deposited to the desired two-dimensional (2D) and three-dimensional (3D) positions rapidly. Many successful applications have been achieved using this technology in tissue engineering and regenerative medicine^1-9. In this paper, a bioprinting platform was established with a modified Hewlett-Packard (HP) Deskjet 500 thermal inkjet printer and a simultaneous photopolymerization system. Synthetic....

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Protocol

1. Bioprinting Platform Establishment

The printer modification was based on a HP Deskjet 500 thermal inkjet printer and HP 51626a black ink cartridge.

1. Remove the top plastic cover of the printer and carefully detach the control panel from the cover.
2. Detach the 3 cable connections between the printer top portion and base. Remove the printer top portion from the base.
3. On the printer top portion, remove the small plastic and rubber accessories (printhead cleaning system) at the right hand side under the ink cartridge.
4. Remove the base of the paper tray with springs.
5. Remove the metallic pl....

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Results

The modified thermal inkjet printer was capable for cell and scaffold deposition at high throughput and excellent cell viability. Combining with simultaneous photopolymerization and photosensitive biomaterials, this technology is able to fix the cells and other printed substances to the initially deposited locations. According to the properties of the modified thermal inkjet printer, the 2D printing resolution was 300 dpi with a single ink drop volume of 130 pl. There are 50 firing nozzles in each printhead with 3.6 kHz .......

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Discussion

This 3D bioprinting system with simultaneous photopolymerization capacity provides a significantly greater printing resolution than the best previously reported method of in situ printing of osteochondral defects using syringe extruded a cellular alginate hydrogel¹⁶. Higher printing resolution is particularly critical for cartilage tissue engineering to restore the anatomic cartilage zonal organization. Simultaneous photopolymerization during layer-by-layer assembly is crucial to maintain precise depo.......

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Materials

Name	Company	Catalog Number	Comments
HP Deskjet 500 thermal inkjet printer	Hewlett-Packard	C2106a	Discontinued. Purchased refurbished from internet vendor.
HP black ink cartridge	Hewlett-Packard	51626a
Ultraviolet lamp	UVP	B-100AP
UV light meter	General Tools	UV513AB
Zeiss LSM 510 laser scanning microscope	Carl Zeiss	LSM 510
Dulbeccos Modified Eagles Medium (DMEM)	Mediatech	10-013
Penicillin-streptomycin-glutamine (PSG)	Invitrogen	10378-016
Accutase cell dissociation reagent	Invitrogen	A11105-01
Phosphate buffered saline (PBS)	Invitrogen	10010-023
Live/Dead viability/cytotoxicity Kit	Invitrogen	L-3224
Poly(ethylene glycol) diacrylate (PEGDA)	Glycosan Biosystems	GS700
Irgacure 2959	Ciba Specialty Chemicals	I-2959
Human articular chondrocytes	Lonza	CC-2550