Right now I am just doing research not the actual discipline of bioengineering. But I am researching Error-correcting codes for DNA Computing. Which is very interesting, I think bioengineering would be actually putting this to the test. DNA Computing is being researched and worked out currently, it probably will not be publicly available for awhile (decades). Google it though, it is amazing the power that is possible. One artificial gram of DNA promises to store as much data as all the computers in the world and the computing power that is possible with DNA is amazing. They are expanding on this concept, making "good" code words.
You might also want to check out quantum computing, which is not in the Bio discipline but also seems interesting. Bioengineering depending upon which school you go to will focus more on biology engineering then implying computer science to the mix. There are hundreds of other things bioengineers would be doing, although this is the one im most familiar with. One idea is to check several of the top schools and see what they are researching in their bioengineering program. Also stop in at the colleges you are thinking about going to and ask the professors there what kinda stuff they do/work on and what you can expect. Getting opinions from numerous people is always a good thing, then go with what you want to do.