Jet‐based methods to print living cells

Abstract

Cell printing has been popularized over the past few years as a revolutionary advance in tissue engineering has potentially enabled heterogeneous 3-D scaffolds to be built cell-by-cell. This review article summarizes the state-of-the-art cell printing techniques that utilize fluid jetting phenomena to deposit 2- and 3-D patterns of living eukaryotic cells. There are four distinct categories of jetbased approaches to printing cells. Laser guidance direct write (LG DW) was the first reported technique to print viable cells by forming patterns of embryonic-chick spinal-cord cells on a glass slide (1999). Shortly after this, modified laser-induced forward transfer techniques (LIFT) and modified ink jet printers were also used to print viable cells, followed by the most recent demonstration using an electrohydrodynamic jetting (EHDJ) method. The low cost of some of these printing technologies has spurred debate as to whether they could be used on a large scale to manufacture tissue and possibly even whole organs. This review summarizes the published results of these cell printers (cell viability, retained genotype and phenotype), and also includes a physical description of the various jetting processes with a discussion of the stresses and forces that may be encountered by cells during printing. We conclude the review by comparing and contrasting the different jet-based techniques, while providing a map for future experiments that could lead to significant advances in the field of tissue engineering.

Creating Transient Cell Membrane Pores Using a Standard Inkjet Printer

“…The printer can be useful in analysis in many fields, including but not limited to: single cell mechanics, tissue engineering, gene transfection, biosensor micropatterning, and direct cell therapies. [1][2][3][4][5][6][7][8][9][10][16][17][18][19][20][21][22] In this example, an HP Deskjet 500 printer and HP 26 series ink cartridges were modified for bioprinting. Using this printer setup with a bioink consisting of a fibroblast cell suspension in a g-actin monomer solution, cells were printed onto glass microscope coverslips.…”

“…[2][3][4][5][6][7][8] This modified printer setup can be used for applications other than cell printing. [16][17][18][19][20][21][22] Matrix proteins, such as collagen or fibronectin, can be easily printed onto substrates with this technique, which can be useful for cell patterning. For instance, collagen type I printed into line patterns will result in aligned collagen substrates that can be used for in vitro cell culture studies.…”

Advances in bioprinted cell-laden hydrogels for skin tissue engineering

“…The distinctive feature between such processes is the inclusion of either an optical absorbing material (MAPLE DW) or a sacrificial absorbing layer (BioLP) at the interface between the laser-transparent ribbon and the material to be transferred [128,163]. In BioLP, the laser absorption interlayer, usually a thin metal coating (Au, Ag, Ti, TiO 2 *100 nm), displays several functions, such as: (1) eliminate the interaction between the laser and the biological material, (2) protect cells from light exposure, (3) minimize the bioink heating, (4) promote a quick thermal expansion with a more efficient droplet ejection, and (5) increase the printing reproducibility [14,57,128,165].…”

“…As a result, these processes are promising as they allow the combination of biomaterials and cells in 3D environments, enabling the formation of close cell-cell and cell-matrix interactions. In contrast to inkjet, laser-assisted bioprinting enables the processing of bioinks with a broad range of viscosities (1-300 mPa s -1 ) and higher cell concentrations (10 8 cells mL -1 ) [59,89,125,165], which is a prime requisite to mimic the native organization of human tissues. Although the absence of an orifice reduces the stresses to which cells are subjected, cell injury and dysfunctionality may occur due to thermal heating, optical irradiation and mechanical impact with the receiving substrate [57,128,165].…”

“…In contrast to inkjet, laser-assisted bioprinting enables the processing of bioinks with a broad range of viscosities (1-300 mPa s -1 ) and higher cell concentrations (10 8 cells mL -1 ) [59,89,125,165], which is a prime requisite to mimic the native organization of human tissues. Although the absence of an orifice reduces the stresses to which cells are subjected, cell injury and dysfunctionality may occur due to thermal heating, optical irradiation and mechanical impact with the receiving substrate [57,128,165]. Previous research has shown that these effects can be significantly reduced, or even eliminated, by controlling the laser pulse characteristics, the bioink viscosity, the thickness of absorbing layer and the substrate properties [27,53,101].…”