Take a look at these ETFs. They should be lower risk that individual companies. Maybe dabble in that, then research their holdings if you really want to get into individuals.
Without expert-level domain knowledge, you are just gambling when it comes to individual investment in nanotech, especially at the startup stage. Better off throwing your money at a firm that has already hedged their bets according to industry experts' advice. Or just put it into an index fund and call it a day.
I'd be reading sites such as https://phys.org/nanotech-news/ to get an appreciation of what's being developed and then think about what's _not_ being developed, and then search for those. Of course, investing can have many profiles. It's easier to get opinions on slow and steady bets, but harder to get good opinions on riskier, disruptive tech...there's no substitute to doing your own research with the latter.
Why do you want to do specifically that? Buffet advises to only invest in your circle of competence.