content: Probably this. Of the worthy journal papers I see, machine learning (training neural nets using experience or Monte Carlo simulation) this has shown the most contribution. Even kids can do it with training.  The other is sensors. Biosensors for detection of smoke, blood urine analysis and other toxins/early warning indicators.  First above is innovation, second is driving costs down.  It sounds more like OP is trying to get the inside skinny on investment opportunities. Most of these companies are private or worthy universities who sell the patents to VCs. Can't just go to your Fidelity or Schwab account and buy a bunch of penny stocks. If that is the case look at investing in biotech VCs or IC fab processes. These are the pinch points, but be careful, these things are either very successful or go the other way and bite you in the ass.  For VCs you have to find out who runs the show at the firm. Success follows people, not things or ideas.