Mayor Thomas Menino was among many officials celebrating the “topping off” ceremony Tuesday at the BioSquare Discovery and Innovation Center, a high-tech medical center on the Boston University Medical Campus.

The ceremony took place as the 160,000-square-foot building received the last piece of steel at its highest point.

A steel beam holding a tree and an American flag was raised to the bottom of the seventh floor of the eight-story building. The tree is meant to bring good luck to the building and its construction. The beam was signed by ironworkers and others in attendance.

The building will be the first commercial lab in Boston certified by the Leadership in Energy and Environmental Design. It is scheduled for completion in October 2005.

BU Senior Vice President Richard Towle said he expects the new building will provide BU graduate students and outside tenants with research opportunities.

“We’re trying to create a scientific village,” Towle said.

Glen Comiso, Boston’s economic initiative deputy director, said Menino believes that biotechnology is the future of the city.

Comiso serves as director of Menino’s Lifetech Boston Initiative, a project started earlier this year to bring more biotech companies to the city. The goal of the initiative is to create 10,000 biotech jobs by the year 2010.

Comiso said biotechnology is a large and fast-growing industry with jobs for people from many different education levels.

The laboratory will include classroom and research space while about 40 percent of the space will house other biotech companies, said Michael Donovan, BU associate vice president.

Thomas Moore, acting BUMC provost, spoke at the event because President ad interim Aram Chobanian was unable to attend as he is still recovering from his recent heart surgery.

President emeritus John Silber was also in attendance.

Darnell Williams, president of the Urban League of Eastern Massachusetts, said he attended to show his support for the project.

Williams said the organization believes residents will benefit from jobs created by BioSquare and the research being done there.

The BioSquare Discovery and Innovation Center, a start-up facility for biotech companies, is also included in the project.

The BDIC will be available to companies developed by BU students and graduates, Donovan said.

BDIC is located less than 10 minutes from downtown Boston at 670 Albany St.