Biotech company Celsion Corp., in Lawrenceville, announced Friday that institutional investors have agreed to purchase $15 million of the company's securities in a direct offering.

Celsion agreed to sell 15,000 shares of its preferred stock — convertible into a total of approximately 12.1 million shares of common stock — and warrants potentially exercisable for up to approximately 6 million additional shares of its common stock. The estimated net proceeds to Celsion are expected to be approximately $13.8 million.