Pseudo-cartridge created for testing the pumping system
ABOUT
In summer 2016, I headed down to Claremont, CA as an engineering design intern at Keck Graduate Institute. Professor Angelika Niemz‘s research group was working to develop a point-of-care diagnostic device able to amplify and detect of Mycobacterium tuberculosis (M.Tb) DNA from sputum. Essentially, disinfected sputum is inserted in the cartridge and the cartridge is mounted on the accompanying electronic platform. Cells are lysed for DNA collection, and different buffers push the DNA to a reaction chamber with a dried master mix for LAMP (isothermal amplification). The final amplified mixture is pumped onto a lateral flow strip for detection.
CONTRIBUTIONS
I focused on redesigning specific components of the cartridge:
- Electrolysis-driven pumps (troubleshoot issues with pressure venting and pump rates)
- Amplification reaction chamber (customizable injection mold design for rapid production of prototypes)
- Lateral flow strip detection chamber (optimizing location and amount of pressure applied along strip)
Along the way, I taught myself how to use the in-house CNC mill for machining the aluminum, HDPE, and acrylic testing jigs that I designed in SolidWords. When I created the customizable injection mold, I also had the chance to use the in-house injection molder to mass produce prototypes of the polypropylene reaction inserts for the biologics testing team.
Beyond technical skills, I was exposed to the design process for point-of-care devices and the reasoning behind material and process selection. For example, LAMP was chosen instead of the more popular PCR due to the isothermal nature: temperature cycling required by PCR is associated with higher costs not suitable for low-resource settings.
Skills
CAD (SolidWorks), CNC milling, Injection mold design and fabrication, Design for manufacturing and assembly, Iterative Prototyping, Microfluidics