Endra Life Sciences Inc. said it closed a previously announced public offering for gross proceeds of about $3.1 million.

The Ann Arbor, Mich.-based developer of medical imaging technology sold 1,285,000 common shares for $2.10 apiece as part of the offering.

Further, the underwriter fully exercised its over-allotment option to buy an additional 192,750 common shares at the public offering price.

National Securities Corp. acted as sole book-running manager for the offering.