March 24 (Reuters) - Thermo Fisher Scientific Inc, the world's largest maker of scientific instruments, said on Sunday it has agreed to buy Brammer Bio in a roughly $1.7 billion cash deal.

Brammer Bio is a vector contract development and manufacturing organization (CDMO), and is expected to post $250 million in revenue for 2019, Thermo Fisher said in a statement.

(Reporting by Joshua Franklin in New York; Editing by Sandra Maler)