PITTSBURGH (AP) -- Federal Reserve Chairman Ben Bernanke toured several life sciences companies in Pittsburgh on Wednesday and touted the former Steel City as a place that has "re-engineered itself."

Bernanke spoke at the biomedical business incubator called the Pittsburgh Life Sciences Greenhouse. The public-private partnership is located on the site of a former steel mill and a visible example of how the city has transformed its economy and industry.

"Pittsburgh certainly is one of the most remarkable examples of a city that has re-engineered itself," Bernanke said.

Before greeting business leaders, Bernanke visited companies like Diamyd, which is developing a diabetes vaccine, and Cardiorobotics, which is making robotic cameras used in surgeries. The visit was part of a meeting held by the Federal Reserve Bank of Cleveland and the Pittsburgh Technology Council.

Business owners talked about the challenges facing their companies, including finding funding, local transportation hurdles and attracting talent to Pittsburgh.

Mark Sniderman, executive vice president and senior policy officer of the Federal Reserve Bank of Cleveland, said that although Pittsburgh's population growth has been sluggish, it has done well in growing innovative companies and an educated work force.

"The challenge is can Pittsburgh keep doing that," he said. "There's promise here in this huge shift we're seeing in Pittsburgh."

Sandra Pianalto, president of the Federal Reserve Bank of Cleveland, said the group has been researching what makes an area grow and Pittsburgh is proving the findings are right on.

"There are two critical ingredients: education and innovation," she said.