Microfluidics Platform

To optimize DNA synthesis using our De Novo Synthesis BioBrick, a microfluidics platform is being developed. It is unrealistic to have a lab worker pipetting for hours upon hours to produce large DNA sequences. Our system would greatly aid in the process by simplifying and automating the process.

This robotic arm is the first scaled down version of our automated system. This device was constructed in order to facilitate element timing using our in house TdT. The robotic arm, powered with a Printrboard, would lower the microfuge tube into the appropriate water baths for the experimental time periods. Peristalsic pumps made from common NEMA-17 stepper motors, would pump in and out the correct solutions in the any deesired sequence. Between cycles, the DNA would be held in the tube using an electromagnet and the solution would be rinsed in preparation for the next cycle. The electromagnet would also allow indirect agitation of the DNA in the tube by rapidly switching its polarity. This device can deliver volumes as low as 10μl, making the robotic arm more an efficient "macrofluidic" device. Although it seems complicated, many of the parts are the same as those found in the typical 3D printer and can be easily sourced.

Dipping Arm

Parallelogram arm with turret base allows for two degrees of freedom: up/down and left/right.

Peristalstic Pump

Universal NEMA-17 peristalsic pump. It uses 2mm silicon tubing and four 8mm bearings. The blue shell and inner hub are 3D-printed.

Assembled Prototype

Upper Left: The Printrboard is usually used for controlling 3D printers, but minor modifications to the firmware allow for custom movements and arm control as well as temperature and heating control for the water baths.
Upper Right: The universal face plate of the NEMA-17 line of stepper motors means this peristalstic pump assembly can be used with any size NEMA-17 stepper without modification allowing the user to choose torque, speed, and price of the pump.
Lower Left: The Eppendorf tube is held at the end of the parallelogram and can be lowered into the desired water bath. A small 0.8mm hole is lased into the bottom tip, which is too small for water to flow through without the aid of a pump. The waste pump can then pull the solution through the hole while the other pumps feed into the top of the tube using an array of 2μl pipette tips.

Micro Sketch

In order to minimize the consumption of our in house TdT and other reagents, a microfluidic device would be a more ideal platform for automation. The microfluidics platform has not yet been completed and is still in progress. We are hoping to prototype out a 10-50x scale version from a 3D print before pursuing soft lithography.