Team:USMA-West Point/Design
USMA-West_Point
Design
Plasmid Design
Device Design
Device Design Overview
Following the successes at West Point with Axion's Muse, a new challenge was brought upon to conduct the same tests but in a more economic fashion. We decided to engineer a similar system with the bioreactor as the main focus. The bioreactor is printed from FormLabs Form 2 printer using a non-cytotoxic Dental SG resin. We designed the bioreactor to allow for neurons to be cultured on a microelectrode array (MEA), to measure activity. The various ports allow media to flow through the system as well as the injection of the olfactant.
The fluidics component relies on a pressure system to maintain flow of media. Because the entire design is a closed system, pressure changes in one area will transmit to fluid flow, be it air or media. We utilize this property to ensure movement of media from the media reservoir to the waste without waste media cycling back through, instead the air is cycled. We also include the use of syringes and luer locks to facilitate any change in pressure, i.e. adding olfactant, by using them for pressure relief.
Microelectrode Array (MEA)
The MEA was designed to hold the cells and register their electrical activity. The MEA consists of electrodes to which the cells adhere, leads that transport the signal, contact pads that transfer the signal to a circuit board, and a layer of insulation. Due to complications in manufacturing a custom design, we resorted to purchasing prefabricated MEAs. Two different MEA designed were purchased, standard and perforated.
Bioreactor
A bioreactor was designed to create a closed system that would hold the MEA and be able to capture the neurons’ output signal the neurons. Autodesk Inventor was used to establish a design and the parts was printed using a 3D printer (FormLabs Form 2). The bioreactor was comprised of two separate pieces, a top and a bottom, that were connected by screws. The top of the bioreactor contains several different ports and internal channels.
Perfusion System
Since the bioreactor created a closed system, a perfusion system was developed to allow continual media flow keeping the cells alive without exposing them to the atmosphere, avoiding potential bacteria contamination. This was done by using a peristaltic pump which regulated the flow of media through the system. Once the flow rate and target volume were set, the pump was started. Olfactants were injected onto the cells through a syringe in the vented screw port at the top of the bioreactor. As olfactant was introduced, pressure was kept constant by withdrawing media and air from another syringe on the other vented screw port on the top of the bioreactor.
Signal Processor
In order to obtain a voltage reading from the neural activity, the signal was transferred from the MEA to a computer. This was done by contacting eight spring loaded pins with the contact pads on the MEA, and by soldering them onto an electrode adapter board.
