Image courtesy of DiMella Shaffer

A Lexington property that’s being redeveloped as 345,000 square feet of office and lab space has been acquired by New York developer North River Co. for $38.7 million.

The seller was ASB Capital Management of Bethesda, Maryland. Lincoln Property Co. led the permitting for the 91 Hartwell Ave. project, which received final approvals last November for a mixed-use campus designed by DiMella Shaffer.

The project includes construction of a new two-story lab building and 502-space shared parking garage next to an existing three-story office building. The redesign creates 95,000 square feet of lab space and 125,000 square feet of office space connected by a center atrium.

Lab vacancies in the Route 128 West submarket sit below 3 percent, according to CBRE’s second-quarter MarketView report.  Average asking rents of $71.63 per square foot are the highest of all suburban Boston submarkets.

North River Co. also has been active in Somerville’s growing life science cluster with its recent proposal for a 200,000-square-foot lab complex at 28 Fitchburg and 28 Chestnut St. in the Brickbottom section.