Team:NTU-Singapore/Design
Shezensor 1.0
The Concept
As MFCs have the potential to be used as a biosensor which is able to detect various chemicals and produce an electrical output. The ability to convert chemical to electrical signals gives MFCs an advantage over biosensors which rely on chemical outputs, i.e. fluorescence proteins as the electrical output allows on-field monitoring, automated data collection as well as WIFI communication.
For our project, our idea to make a portable device which allows users to test the cleanliness of water samples. Our device has two important components, the reader and the sensor. The reader is an arduino-controlled voltmeter and has a 16x2 LCD screen which provides a voltage reading to the user. While the sensor is a disposable cartridge which houses the MFC. Liquid samples can be loaded into the sensors and plugged into the reader to check if the voltage reading. After designing the cartridge, we carried out a proof-of-concept experiment to test the feasibility of our concept by first testing whether our disposable cartridge works.
Design
As mentioned in the concept, we will be using the Arduino board as the voltage reader, hence, the programming for the Arduino board has to be done so that it can be used along with a LCD display screen. On the reader, a cartridge port was made to allow connection of the anode and cathode to the reader.
For the cartridge, the materials we used were acrylic blocks and Booby helped carve the block outs as the machines are highly dangerous. The internal dimensions are 60 X 20 X 5mm, while the dimensions of our carbon cloth is 50 X 20mm. The area allowed for the proton exchange membrane is maximised to increased voltage output, with an area of 60mm2. When all the parts are carved out with the help of wonderful Bobby, we glued them together with a specialised acrylic glue and made sure that no leakage happens.
P.S. Our first prototype leaked, and we made another one. :P
The Blueprint.
The Catridge.
The Reader.
Testing It Out
We wanted to test whether our cartridge would work. Hence, we culture Shewanella oneidensis MR1 containing the lactate permease and lactate dehydrogenase operon and used it for our cartridge. The measurement was made both with the Arduino as well as a multimeter as we would like to have a comparison of any deviations from the multimeter. However, no significant deviations was detected as the values reflected in the Arduino closely matches the value in the multimeter.
Kean Hean making final adjustments to the reader. :)
Walla!! Shezensor showing initial readings. On the right side is the cartridge port.
Shezonsor and friend!! :)
