Generating Microfluidic Systems
The Integrated biofabrication platform that is TSIM® and the BioAssemblyBot® 400 enables the intuitive fabrication of microfluidic systems
Generating microfluidic devices commonly involves forming polydimethylsiloxane (PDMS) molds, of a specific channel design, from soft photolithography. This is often time-intensive, making iterations of a channel design effort less efficient. In Advanced Solutions Life Sciences’ integrated biofabrication platform, numerous different channel systems can be digitally prototyped in the TSIM® software environment, and automatically fabricated with the BioAssemblyBot® via sacrificial 3D printing, providing an easy and fast way to fabricate microfluidic systems optimized for a particular application.
Within TSIM®, you can utilize sketching tools to create a channel design of interest within each well of a multi-well plate or a custom device. Each component of the design is then assigned a sacrificial material in a printing cartridge fitted with different caliber nozzles. The platform will begin printing the sacrificial material in the channel network pattern, automatically switching between the different tools as needed to complete the network. After the material of the device (e.g. acrylates, collagen, etc.) is flooded and cured around the printed network, the sacrificial material is flushed away leaving behind patent channels within the matrix material. These channel systems are then connected, via integrated inflow and outflow ports, to a pump/fluids management platform to provide perfusion throughout a 3D tissue construct.
Designing channel structures within TSIM®
Within the software program, TSIM®, the different channel elements that make-up a microfluidic network are created de novo based using the sketch features. A single network can be created (shown below) or multiple networks created with each one being placed in each well of a multi-well plate. TSIM® enables the import of 3D model files of standard multi-well plate formats for this purpose. Of course, a different network design can be created for each well, if desired. After the overall channel design and organization is determined, each component of the structure is assigned a material/tool which includes the relevant nozzle size and printing parameters. In TSIM®, each of the microfluidic elements assigned with a specific material/tool is indicated with a different color (Figure 1). Importantly, network designs can be exported by the TSIM® software program for estimating hemodynamic parameters using computational fluid dynamics programs.
Printing the microfluidics platform using the BioAssemblyBot® 400
Next, the digital model of the microfluidic network is sent from TSIM® to the BioAssemblyBot® 400 for fabrication. Once the requisite tools are loaded, the BioAssemblyBot® then executes the fabrication run, seamlessly changing out each tool, as required. Although the same material, in this case, Pluronic hydrogel, is being used to fabricate the structure, the tools are being interchanged to automatically incorporate different nozzle diameters to achieve the targeted channel diameter. The last step of this fabrication process includes the tool pathing capability of the BioAssemblyBot® 400 to generate a structure in a single upward motion to fabricate the inlet and outlet ports that will directly contact with the fluidics management device (Figure 2). After each component of the network is printed, the system is then covered with the desired matrix material such as uncured acrylate or non-gelled collagen (Figure 3).
After the network is printed, the surrounding matrix is gelled (or cured), and the device is connected to the fluidics management or pump system, the printed material is flushed out, leaving behind patent channels for experiments on flow characteristics or cellularization facilitating perfusion of 3D tissue models/constructs.
To learn about the BioAssemblyBot 400, click here.