Team:GreatBay United/Hardware
Hardware
Introduction
Artificial Limulus amebocyte lysate is aimed to detect gram positive bacteria by detecting the LPS (lipopolysaccharide) part of bacterial endotoxin. By giving visual test results, Artificial Limulus amebocyte lysate have a wide range of applications in daily lives as no professional equipment is needed. As it replaced the function of limulus amebocyte lysate whose main component is tachypleus amebocyte lysate blood, it can contribute to the protection of tachypleus amebocyte lysate who is already endangered.
Introduction of Hardware
On this page, the process of brainstorming, designing, building, checking errors, rebuilding, and, eventually, succeeding will be displayed accompanied by our different versions of hardware that have always inspired us to further study them.
Experiement-related
According to the cascading system's mechanism, all cascading reactions should be carried out at around 37 Degrees Celsius, otherwise, the reaction rate will be greatly affected. What's more, PSA is a protein that works in the human body, and its optimal temperature is around 37 Degrees Celsius. Therefore, the detection system based on the allosteric protein of PSA also needs to work at about 37 Degrees Celsius.
The general ambient temperature is lower than 37 degrees, so we planned to make a piece of hardware that could heat the water to reach 37 Degrees Celsius and maintain the temperature for as long as the detection required. In this way, the temperature problem could be tackled with heating systems.
Since the final determination of the presence of endotoxin is determined by agglutination, the reagent is stored in a transparent container. Therefore, we decided to use centrifugal tubes as the inner container for the reagent.
Materials and components
In general, we used centrifuge tubes, heating and temperature control plates, and an inner and an outer containers that mainly functioned as a miniature water bath. The heating and temperature control plates were bought from Taobao and Jingdong, two online shopping applications, and the main container was 3D-printed.
Heating module:
Heating module for aluminum oxide shell wrapped metal tungsten wire. Once electrified, it would heat the water in the container.
Temperature control module:
The temperature control module is a miniature motherboard, which can actively control the on-off of the circuit through the relay to adjust the target temperature.
AC 220V to DC 12V adapter:
Since the heating and temperature control modules operate at 12V, and most people do not have a 12V DC power supply, an adapter is necessary. In this way, as long as there is an AC 220V socket, the system can work.
Containers (3D-printed) :
The container lid has four holes to hold four centrifuge tubes. No. 1 is a negative control, No. 2 is a positive control, and No. 3 and No. 4 are used to detect endotoxin. The protruding part on the side of the lid makes it convenient to open the lid. The heating plate is put on the bottom. There are three holes in the wall, one for plugging the temperature probe, and the poles of the heating plate protrude from the other two holes.
Generations updation
The first generation mainly focused on the inner tank and the most pragmatic and necessary part of the entire hardware. We started designing and refining this generation steps by steps.
Version 1: Basic inner tank
Product Description: the small inner tank had four holes for the four centrifugal tubes. The heating plate was designed to be attached to the wall of the tank, while the temperature control plate was connected, but not attached to the wall. Drawback: the material that the 3-D printing machine used was plastic, which had poor heat conductivity. In order to save energy, avoid overheating, and improve efficiency, the heating plate should not be attached to the surface. Instead, it should be put inside, heat water directly.
With no experience in using 3D printing machines, we faced our first obstacle when we printed the first version of the hardware. A mistake on 3D-printing modeling on Solidworks was made, causing the surface of the inner tank to be rough and imperfect. After amending the modeling, we solved this problem.
Version 2: Basic inner tank with heating plate placement_Failure
Product Description: In order to save energy, avoid overheating, and improve the efficiency, the heating plate should not be attached on the surface. Instead, it should be put inside, heat water directly. Therefore, we put the heating plate inside the inner tank. Drawback: However, we made a mistake once again when we modelled the draft on Solidworks. It turned out that the entire heating plates were still covered by a layer of plastic, not functioning as we expected.
Version 3: Basic inner tank with heating plate placement_Success
Product Description: This time, we successfully printed out an appropriate place for the heating plate, which was located at the bottom of the inner tank, intentionally put away from the temperature detecting equipment to avoid inaccuracy. Hot-melt adhesives were utilized to seal the connection for the avoidance of water leakage.
Drawback: Hot-melt adhesive, according to our experiment, was not the best glue for sealing connections that water might permeate. The solid hot-melt adhesive would not tend to cling to the wall of the plastic inner tank, starting to fall and causing water leakage.
Improvement: We then used glass glue to seal the connection. Since glass glue's stickiness would not be influenced by water, this worked well.
Generation 2: The outer tank
This generation mainly focused on the outer tank that functioned as a cover to make the entire hardware more aesthetically good-looking by concealing wires inside.
Version 1: Outer tank with errors
Product Desription: In order to conceal the wires into the entire hardware, the outer tank was produced by 3D-printed machine. A space was specifically left for the screen on the temperature plate, and there were grooves at the bottom of the outer tank to stable the placement of the inner tank. Drawback: Due to inefficient communication between team members, the outer length and the inner length of the inner tank was miscalculated, causing the inner tank (shown on the left) unable to fit into the outer tank (shown on the right).
Version 2: Size change_Failure due to tech issue
Product Description: We rearranged the setting on Solidworks and modelled another new outer tank in its right size. However, due to overwhelming working for hours for many days, tech issue occured. The 3D-printer stopped in the middle of printing, and there was no enough plastic material for printing more.
Version 3: Success
Product Description: After changing the size of the outer tank and preparing enough material for printing, the final version of the hardware was produced.
