Fabricating Cell-Based 3D Tissues with BioAssemblyBot

Cells can be used as an ‘ink’ for the BioAssemblyBot® platform to generate precise 3D constructs

One of the major differentiating factors between other types of additive manufacturing and bioprinting is the incorporation of biocompatible material and/or cells to create 3D tissues and tissue models. Therefore, when utilizing a technology platform in the context of biofabrication, it is imperative that the platform can successfully print cell-laden materials or cell preparations alone precisely and without harm to the cells. The BioAssemblyBot® platform achieves both.

The Process

Isolated cells are first loaded into syringes within the sterile environment of a biosafety cabinet or hood. The syringes, while capped, are then loaded into the appropriate tool body based on the fabrication task at hand, which are then placed into the associated storage bay within the BioAssemblyBot® enclosure as designated by the integrated TSIM® software program. To maintain a sterile environment within the enclosure of the BioAssemblyBot® platform, the HEPA filtration system will need to be kept on, the switch for which is located on the touch-screen interface attached to the platform. Below are examples of either a heterogeneous primary cell-isolate or cultured cells printed using the BioAssemblyBot® platform.

Cells Printed with the BioAssemblyBot® Platform Exhibit High Levels of Viability

Figure 1: Percent viability of ASF cells 7 days post hand-pipetting (not-printed) versus having been printed on the BioAssemblyBot® exhibits no significant difference.

Cells of the human adipose stromal fraction (ASF) were printed under ambient conditions in the BioAssemblyBot® platform and were suspended in standard growth medium. The percent viability of cells that had been printed were compared to those that had been hand-pipetted into wells of a multi-well plate. After 7 days of culturing, there was not a significant difference in percent viability between these two cell populations (Figure 1).

Cell Populations Are Precisely Localized Within 3D Constructs When Printing with the BioAssemblyBot®

Human Umbilical Vein Endothelial Cells, or HUVECs, were suspended within 3mg/ml of cold, pH neutral type I collagen at a concentration of 2 million cells/ml and loaded into the BioAssemblyBot® cold tool to prevent gelation. This cell/collagen suspension was then printed inside of 400 μl of un-gelled collagen within a well of a 48-well plate with the print stage temperature set to 25°C during the print. The cell/collagen mix was printed in a 3D line as shown in the schematic and accompanying images. Blue dye was added to the cells/collagen to visualize the printed path. (Figure 2).

Figure 2: Pattern of printed HUVEC cells within a single well of a 48-well plate and the resultant print a collagen gel.

The ability of the BioAssemblyBot® platform to fabricate 3D constructs out of primary and cultured human cells while maintaining viability and spatial control is key towards the utilization of the system to create complex tissue structures. From design to fabrication, the BioAssemblyBot® enables physiologically relevant tissue generation in a biocompatible manner.