Was it only three years ago that Radar Magazine crowned Drexel University the "ugliest campus" in a roundup of American colleges? The charge seemed a bit unfair then, even if Market Street was still ablaze with Drexel's orange-brick relics. But it's clearly wrong today.

Driven by the revved-up agenda of its late president, Constantine Papadakis, Drexel has cleaned up nicely in the last few years. The university has added several distinctive dormitories, camouflaged its orange-brick gym with a gossamer glass wall, and brought an important building by Robert Venturi and Denise Scott Brown into the campus fold.

The latest evidence that Drexel has moved to a higher tier, architecturally speaking, may be the very fine biology building about to open at the corner of 33d and Chestnut Streets. As a parent who spent the past year traipsing across dozens of college campuses (it felt like dozens, anyway) with an aspiring astrophysicist, I can report that the new Papadakis Integrated Sciences Building holds its own against any of the deluxe new labs I saw in my travels. It gets extra credit for doing so on a tough urban corner.

It's no accident that the exterior of the $69 million building is covered with limestone. It's an ambitious reference to the pale terra-cotta on Drexel's original home, the historic, Renaissance-style Main Building, two blocks east.

While that building celebrates engineering, the Papadakis is a paean to biology. You see it the moment you step into the atrium - another reference to Main - where a coiled stair evokes DNA's double helix and an 80-foot-high wall of plants serves as a living air filter. Natural light laps at the space. You could spend a day inside and not feel the least sun-deprived.

There is hardly a college today that isn't rushing to build its own version of Papadakis. We're living in a Sputnik moment, but for biology. Thanks to the huge interest in public health, the human genome project, and the effects of climate change, biology departments have secured big money from donors to construct temples to science.

The Papadakis building is a manifestation of that trend. Drexel's biology department was working out of decrepit labs in a 1950s, orange-brick (of course) building that didn't have air-conditioning. Some labs even lacked windows - not the best environment for running a temperature-sensitive experiment.

Once Drexel decided to remedy the situation, it departed from the usual formula. The university held a competition to select a lead architect, and involved the biology faculty in the design discussions. After choosing Toronto's Diamond & Schmitt Architects, it assigned two professors, Aleister Saunders and Jacob Russell, to work with the Toronto designer and H2L2, the local architects who oversaw construction.

The value of their collaboration is visible throughout the building. We tend to think of labs as chilly, functional spaces, with their long rows of soapstone work tables and boxy venting hoods. Nowadays, it's just as important for a science building to behave like a skilled party host. Because scientists believe the best ideas originate in casual conversations that occur in hallways and lounges, informal spaces that encourage sociability and serendipitous encounters are crucial.

You know the Papadakis building is going to be a convivial place at the entrance, marked by an elegant, four-story glass cylinder. The transparent tower contains a small lounge on each floor where students and faculty can mingle. The super-clear glass offers spectacular views of the city, where ideas are constantly percolating. At the same time, passersby can glimpse research in progress, or maybe a dozing student.

If the labs of the 1950s were arranged like egg cartons, with rooms off long corridors, today's luxe research spaces are invariably organized around a soaring atrium. They're made for socializing because they function as a crossroads within the building.

At Papadakis, the atrium also serves as a real-time science experiment. The three-sided space terminates with a vertical garden of ficus, arbicola, philodendrons, and rubber plants. They're pretty, but they're also the green equivalent of the fuzzy mesh filter you find in your home heating unit. The recirculated air is said to be as clean as outdoor air, but just to be sure, Drexel's Russell plans to monitor the plants and air as part of his research.

Diamond & Schmitt pioneered the use of such "Living Walls" to remove the unhealthy particles - like formaldehyde and ethyl benzene - that accumulate in the processed air of our buildings. As air is pumped through the 1,500 plants on the atrium's wall, the particles get snagged on the roots. Microbes that make their home on the root fibers then proceed to munch the chemicals for dinner. The technology, which uses a process called phytoremediation, was developed by Canadian biologist Alan Darlington. At the time, he was a university researcher trying to figure out "how to grow tomatoes on Mars." Keeping the air clean was key. Darlington eventually realized the air-filtering techniques could be better applied on Earth.

Working with Diamond & Schmitt, he developed that polyester membrane that allows the plants to grow vertically against a wall. The plants are stuffed into pockets that resemble one of those over-the-door shoe bags. There is no soil, just bare root. A hydroponic drip system, together with the microbes, nourishes the plants - and provides a calming soundtrack of dripping water. Darlington has designed 150 biofilters like this, but Drexel's is the largest in the United States. Even at that scale, the labs need to have their own individual ventilation systems, for safety reasons. But because so much air will be recirculated, Drexel expects to save a bundle on heating and cooling, helping Papadakis qualify for a gold rating from the U.S. Green Building Council.

The open-plan lab spaces also are flooded with natural light. It's a good thing, because otherwise it might be difficult to get anyone to leave the atrium.

Changing Skyline:

Hear two Drexel biology professors talk about how a living wall filters the air at philly.com/


Contact architecture critic Inga Saffron at 215-854-2213, isaffron@phillynews.com or @ingasaffron on Twitter.