One week is not all that long in the great scheme of things, the way that Biotech co's operate! They most likely have another candidate or two to assess in the same way that they did with you, and they are doing this right now. It sounds to me like you have covered all your bases, and you're cued up and ready to be invited back.
I wouldn't let it go another week, however, without touching base with your "champion" there. This may be another scientist whom you had a great discussion with, the prospective boss or in many cases an HR person who arranged the interview. I'd call them the middle of next week and ask about "what the process looks like from here, and if I will have the additional interview that was mentioned as a possibility."
I don't think that could hurt, but yes -- at one week, that may be a bit aggressive.
Dave Jensen, Moderator
“I shall tell you a great secret, my friend. Do not wait for the last judgment, it takes place every day.” - Albert Camus