A lot of mechanical engineers in academia are actually working on (or looking to work on) research that has medical applications, because you can get funding from the NIH. Although academics are technically supposed to be "independent," the funding climate ultimately drives research interests.
> What's that thought process like?
Well, presuming that he was already well aware of the ability to use magnets to move minuscule quantities of iron, it starts out with something like this: http://lmgtfy.com/?q=human+body+iron
Note that it doesn't have to start out with malaria. In fact, you don't have to know anything about human disease when starting out.
What I'd like to see is an open source version of this machine which can be easily reproduced in pure countries.
HOWEVER, smart as it may seem, if I don't see some triple-checked hard-data, it's hard to tell if the magnets approach actually works and here is were professional clinical trials are made. Because in real life it's extremely hard to take say 5.000 blood samples from people who might be infected (e.g. Africans) right down the results, then go to a professional lab and compare the samples. Write down the results, find in which conditions concentration of 'Fe' is high in blood. Probably talking to the IDI[1] would be a nice first step and so on.
"He founded DDG in Cleveland, where he earned his undergraduate degree at Case Western Reserve University. Lewandowski’s cofounder and former faculty adviser, Brian T. Grimberg, is an assistant professor of international health at the university’s medical school, and a specialist in malaria."
Read as much as you can: http://scholar.google.com/scholar?q=malaria
Fighting malaria is something I'm interested in pursuing, but my background is heavily in the computer science arena. How do I go about finding out enough about malaria to be able to actually contribute to the problem? (And I don't mean merely writing a check to the Anti Malaria Foundation or whatever.)