Kennesaw-based CryoLife Inc. is expanding its high tech manufacturing capacity in Midtown. The implantable biological medical device and cardiovascular tissue processing firm has signed a lease for 10,000 square feet of space at Georgia Tech, said Ashley Lee, CryoLife’s chief financial officer and chief operating officer. The space, at 387 Technology Circle NW, was formerly occupied by an Altea Therapeutics, a life sciences company that raised more than $60 million in venture capital and closed late last year after its commercialization partners chose to halt funding. The space was move-in ready and had “clean room” capacity, Lee said. Clean rooms have strictly controlled temperature and humidity to protect equipment from contamination.