Two teams of researchers from New England have built living, breathing lung tissue in the laboratory — feats of engineering that could speed up the development of new drugs and bring researchers a step closer to the tantalizing dream of growing replacement lungs for patients.

Both achievements, described in reports published yesterday by Harvard and Yale scientists, are part of broader efforts among researchers to build a range of organs, from the heart to the liver. Such research could provide powerful tools to test drugs and identify toxins, and eventually grow new tissue to repair damaged organs.

Harvard scientists re-created a critical area of lung tissue on a silicon rubber chip the size of a quarter, and found that it responded to bacteria and tiny particles carried in the air just like a living lung. Using a different approach, Yale University researchers regenerated lungs and transplanted them into rats, where they functioned successfully for up to two hours.

This work is not the first successful effort to build functional tissue. In the late 1980s, researchers first began to apply engineering approaches to human tissue, and advances have begun to work their way into the clinic — most notably in advances in artificial skin.

But the two new studies are significant milestones in the quest to build a functional organ in the lab — although it will still be many years yet before doctors reach the science fiction dream of regenerating lungs to help patients.

More immediately, the benefits of the new work could be seen in allowing pharmaceutical companies to test drugs on a tiny, cheap chip that closely resembles the complexity of the human body.

The “lung is pretty tough [to replicate]. It’s also pretty important — people get lung cancer, and lots of people get lung diseases that are pretty serious,’’ said Robert Langer, a professor at MIT who was not involved in either group’s research. Langer said the new techniques also could provide a substitute for animal testing.

For years, scientists have tested drugs using cells in a dish and lab animals. But many organs have layers of complexity that simply can not be replicated with current models, and drugs that show promise in mice often do not pan out as cures in humans.

The lung contains an intricate branching architecture of airways, blood vessels, and hundreds of millions of tiny sacs, called alveoli, where gases are exchanged. And the cells move and are stretched with each breath.