Just start by entering any of the larger biotech tickers in the Twitter Search box. You'll see the stream. Much of it will be the usual daytraders and wannabees and subscription stock services, no different than message boards. But a few will be discussing aspects of specific drugs, pipelines, testing, the companies themselves at a much more scientific and technical level.
Click on one of those names, go to his full profile, see who he is communicating with. If what he's saying interests you, click Follow. Gradually you'll build up your own stable of knowledgeable experts.
All that is needed to make a happy life is within yourself, in your way of thinking. -Marcus Aurelius