One of the limitations we identified early on in our project was the lack of concise and clear information about microfluidics for researchers in Synthetic Biology. Using the iGEM poll we were able to confirm this suspicion and understand what the synbio community wanted us to design for them.
As a result, the first stage of MARS is increasing the understanding of microfluidics. Under this section we have included a brief introduction to microfluidics as a whole and an explanation of how our continuous flow devices function. A primitive guide has also been included so researchers can identify and understand the function of each element on their chips. This guide can also be used in conjunction with the software tool 3Duf in order to design your own chip, or to adapt and iterate on our designs in the MARS Repository.
Team:BostonU HW/IntrouF
Introduction to
Microfluidics
Microfluidics
Microfluidics 101
Contents
Introduction to Microfluidics
What is Microfluidics?
Microfluidics is the manipulation of microliter volumes of liquid in order to perform scientific experiments. This is performed on devices called microfluidic chips that can be made of polycarbonate, glass or silicone.
What is a Microfluidic Chip?
A continuous flow microfluidic chip typically consists of three layers: a flow layer and control layer with a flexible layer of PDMS between them. There are many other types of microfluidics such as digital or paper which operate using different mechanisms, however we will focus on continuous flow chips as this is the type utilized by MARS.
Material: Polycarbonate
The Control layer of a microfluidic is used to actuate the flexible PDMS layer in order to manipulate fluid flow through the flow layer. For example, by actuating a syringe attached to the control layer, a valve can be opened.
Material: Polydimethylsiloxane
The PDMS layer of a microfluidic lies between the flow and control layers. This flexible membrane allows for a seal to be created between the two polycarbonate layers. PDMS can be actuated to manipulate fluid flow in valved designs.
Material: Polycarbonate
The Flow layer of a microfluidic is the layer that liquid(s) flow through. Etchings on this layer, known as primitives, are used to manipulate and alter fluid flow. For more information regarding primitives refer to the Primitive Table.
How can Microfluidics Apply to Synthetic Biology?
Microfluidic chips can be designed to perform various procedures used in synthetic biology. There are many advantages to integrating microfluidic devices into a synthetic biology laboratory. For example, these devices utilize microliter volumes of liquid which decreases reagent waste, allows for more trials to be performed with the same volume of reagents and lowers costs as reduced reagent volumes can be effectively utilized. Furthermore, complete protocols can be transferred onto a single chip and automated. Due to their microliter handling abilities, multiplexed systems can also be run on a single compact chip. As a result, researchers can save significant amounts of time spent on performing protocols in the lab and simply run a single chip instead. Using our fabrication system, researchers can also rapidly produce microfluidic devices at low cost to easily integrate into their lab environment.
Primitive Table
| Primitive | Design | Mill |
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Channel Carry fluid through the chip and between other primitives Design Parameters: Channel Width Channel Length |
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Ports Used to input or output fluids from a chip. At least two ports are necessary for a single chip, one to input fluid and the other to output it at the end Design Parameters: Port Radius |
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Mixer Mixes two or more liquids together Design Parameters: Bend Spacing Number of Bends Bend Length Channel Width |
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Curved Mixer An iteration on the previous mixer. Mixes two or more liquids together but has improved fluid flow due to its curved design Design Parameters: Bend Spacing Number of Bends Bend Length Channel Width |
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3-D Valve Blocks the flow of fluids through a channel. Can be opened to allow liquid to flow through Design Parameters: Valve Radius Gap Width |
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Circle Valve Used in conjunction with the 3D valve. For any 3D valve on the flow layer, there must be a circle valve placed directly above it on the control layer Design Parameters: Valve Radius |
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Diamond Chamber Can be filled with fluid for various applications, for example to incubate a solution. Design Parameters: Entering and Exiting Channel Width Chamber Length Chamber Width |
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Trees Allows for fluid to be evenly split into two or more separate channels Design Parameters: Channel Widths |
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Transition Provides a smooth transition point between two primitives of different sizes. For example, between channels of width 800um and 1500um. Design Parameters: Entering Channel Width Exiting Channel Width Length |
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Metering Allows for accurate volumes to be measured and dispensed. Made up of valves and channels. Multiple metering sections can be used to dispense different fluid volumes on a single system. Design Parameters: No features listed as this module has yet to be integrated into the existing software system. |
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MARS Tutorial Videos
Summary
In this section you will find our Microfluidics 101 video tutorials. These videos take you through the basics of fabricating and using MARS microfluidic chips. Each is a fully narrated, step-by-step guide teaching you how to mill, make PDMS, and more! For those who prefer reading, each video is accompanied by an in-depth, printable written protocol.
This branch of MARS was validated by our iGEM poll. When we reached out to teams regarding what educational materials they would find useful, one of the highest voted tools were video tutorials with 73.8% of responses indicating video tutorials would help them start using microfluidics. This idea was also pitched to various microfluidic manufacturing companies who advised us on specific elements to include. For example, including written content in the form of protocols was suggested in order to provide a written guide to be carried into laboratory settings or referred to when offline. The inclusion of our “Cleaning” video was inspired by Black Hole Lab’s emphasis on proper cleaning and storage of their chips during training seminars for lab technicians.
This branch of MARS was validated by our iGEM poll. When we reached out to teams regarding what educational materials they would find useful, one of the highest voted tools were video tutorials with 73.8% of responses indicating video tutorials would help them start using microfluidics. This idea was also pitched to various microfluidic manufacturing companies who advised us on specific elements to include. For example, including written content in the form of protocols was suggested in order to provide a written guide to be carried into laboratory settings or referred to when offline. The inclusion of our “Cleaning” video was inspired by Black Hole Lab’s emphasis on proper cleaning and storage of their chips during training seminars for lab technicians.
Microfluidics 101: How to Mill a Chip
Microfluidics 101: How to Make PDMS
Microfluidics 101: How to Assemble a Chip
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