Neptune is Making Custom Microfluidics Systems Accessible

The Bantam Tools Desktop PCB Milling Machine is crucial to CIDAR’s synthetic biology and microfluidics research.

Boston University has long held a reputation as one of the most respected research institutes in the U.S. One branch of the intriguing work being done stems out of the Department of Electrical and Computer Engineering’s CIDAR (Cross-Disciplinary Integration of Design Automation Research) lab, which focuses on advancements in synthetic biology and microfluidics.

What is microfluidics? 

We asked CIDAR graduate researcher and mentor Ryan Silva to break it down for the layperson:

Microfludics is nothing more than moving small amounts of liquid from one place to another; it's plumbing at the micro-scale. Fluids at small scales can behave in useful ways.

The life of a wetlab biologist is dominated by the mundane task of moving small amounts of liquids from one place to another by hand (e.g., by using a pipette). Microfluidics have the ability to automate the most routine, as well as the complex, aspects of daily life in a bio/chem lab. In this regard, it’s easy to see how the field can be attractive to a bio-design automation lab like CIDAR.

Take a closer look at Neptune’s microfluidics project.

The Neptune Project

One of the teams that Silva mentors is called Neptune, and an integral part of their system design is the Bantam Tools Desktop PCB Milling Machine.

What is Neptune? From the project's GitHub page:

Neptune is a complete, end-to-end microfluidic design suite for synthetic biologists. With Neptune, researchers and microfluidic designers have all the tools needed to design, fabricate, and control microfluidic devices. Neptune supports high-level specification of a microfluidic chip's layout and function. This high level specification includes a library of predefined microfluidic components commonly used in designs, including valves, gradient generators, serpentine mixers, and droplet generators. 

Neptune also provides an interface where researchers can control their microfluidic chip in real time. Fluid flow can be manipulated directly from the interface, making Neptune an ideal tool for running and controlling microfluidic chip experiments. Neptune also interfaces with and sources only low-cost, open and readily available tools to fabricate and control microfluidic chips. Neptune provides a 3D-printed control infrastructure for your chip, and fabrication itself leverages the MakerFluidics workflow to create the chip using a CNC mill.

Neptune’s logo.

What was the impetus for creating Neptune? 

The team explains:

Neptune was created with the goal of streamlining the process of designing, building, and controlling microfluidics. More specifically, the Neptune team wanted to reduce the barriers to entry of microfluidics in terms of monetary cost and expertise/time cost.

Monetarily, Neptune saves money by using an alternative microfluidic fabrication process (utilizing the Bantam Tools Desktop PCB Milling Machine/desktop CNC mill) as well as an alternative fluid control process (using custom 3D-printable infrastructure for low-cost servo-syringe combination pumps to sit in). The costs of the desktop CNC and 3D printer are almost negligible compared to the costs of contemporary microfluidic fabrication equipment (~$70K).

In terms of expertise/time savings, Neptune provides an end-to-end user-friendly software tool that encompasses the inception of the microfluidic idea all the way down to its control after it’s been fabricated.

From the top, Neptune utilizes a parametric description of microfluidic design that saves the user from having to manually draw designs in illustrator tools. Instead of tedious redrawing, a simple change of a number can tweak/improve a microfluidic design. This description is transformed into a blueprint that is Bantam Tools Desktop PCB Milling Machine-compatible, as well as a list of control infrastructure parts to be ordered (servos, syringes) or 3D-printed (servo-syringe pump fastenings).

After a few CNC mill and 3D print jobs, the user is ready to assemble the device and control infrastructure, and then take control of their experiment from the Neptune software.

This is what the Neptune homepage looks like.

The Neptune team submitted the entirety of the project, both hardware designs and software tools, to the iGEM (International Genetically Engineered Machine) competition, the premier team competition in the field of synthetic biology. They were awarded gold medals for the project's successes and community outreach efforts, and they were nominated for Best Software and Best Applied Design. 

The Role of the Bantam Tools Desktop PCB Milling Machine

Without the availability of affordable, high-precision desktop fabrication tools, though, this revolution in microfluidics wouldn’t be possible. Silva explains:

CNC-milling microfluidics has been an established fabrication method for at least a decade; however, machines capable of achieving the required tolerances at the microscale started at $15,000 and took up a lot of space relative to a typical chem/bio lab bench.

We tried outsourcing our milling, but the turnaround time approached that of traditional techniques of microfluidic fabrication. Then we discovered the emerging market for desktop CNC mills, led by the Bantam Tools Desktop PCB Milling Machine. The machine, combined with the Bantam Tools Desktop PCB Milling Machine, was an outstanding entry point for approaching the daunting challenge of CAM. The Bantam Tools Desktop Milling Machine Software was extensible, and generated G-code using only the SVGs produced by our microfluidic software.

The Bantam Tools Desktop PCB Milling Machine really changed the game by providing acceptable precision for an order of magnitude less in cost — all in a form factor that fits beautifully on a lab bench. Our first Bantam Tools Desktop PCB Milling Machine was a V2 we purchased in 2015. Since then, our microfluidic research has skyrocketed, to include a device publication in the top journal in the field.

We're thrilled the Bantam Tools Desktop PCB Milling Machine is part of such a powerful project. Cheers to Ryan Silva and the Neptune team! To learn more about the project, head to the Neptune site, the GitHub page, or this walkthrough video:

Amanda Bender