Optical imaging firm VisEn Medical Inc., of Woburn, Mass., announced it has raised $7 million in Series B financing.

Merck Capital Ventures and Flagship Ventures co-led the investment round, which also included The Bollard Group and other existing investors.

Joining VisEn Medical’s board of directors is Per Lofberg, president and chief executive officer of Merck Capital Ventures.

VisEn, which specializes in fluorescence in vivo imaging developed by researchers at the Massachusetts General Hospital and Harvard Medical School, plans to use the money to launch new products and advance the development of its technologies in clinical imaging applications. It is also looking to expand sales, marketing and customer support programs.

Founded in 2000, VisEn works directly with large pharmaceutical partners to design ranges of tailored molecular imaging probes and applications that are targeted to their specific research areas.