Bentley Systems Inc., the Exton-based, $500 million (annual sales) construction and architecture software firm, says it will add 50 employees at its new Center City office over the next couple of years, in the first of what Mayor Nutter hopes will be a string of suburban firms opening city "gateway" offices for skilled staff who'd rather walk to work than fight the Schuylkill.

Bentley customers are expected downtown at the Pennsylvania Convention Center on Tuesday for the company's "Be Together" users' conference. Chief executive Greg Bentley and his brothers Keith (chief technology officer), Barry, and Ray (both executive vice presidents) plan to join Nutter on Wednesday to open the newly leased office in the burgundy-brick tower (home to ExcelleRX, and formerly Reliance Insurance) at 1601 Cherry St.

"We've been working on Bentley for four years. We're excited," the mayor said.

"Bentley relies on people who understand code and software and how to design and market it," and "young talent" that's easier to "lure" to cool downtown locations, Deputy Mayor Alan Greenberger told me. "We're not going to undo" the suburban lifestyle. "But companies are finding the young people they need to attract are living in the city and are not interested in a car commute. We have a list of firms that fit that profile."

Such as the drug companies that line U.S. 202 in the suburbs, whose Center City resident managers reverse-commute, said Nutter: "We're working on them."

Family-owned Bentley isn't likely to face the resistance that publicly traded Unisys Corp. found when it proposed moving its Blue Bell headquarters to Liberty Place, and installing a big sign there, a few years back. The city has space to spare for companies Bentley's size: Class A spaces can be had in the $20s a square foot, a fraction of New York, Boston, or Washington rents.

Small is big

Optofluidics Corp., run by a couple of Ph.D. scientists — Cornell physicist-engineer Bernardo Cordovez and Drexel- and Penn-trained biomedical engineer Rob Hart — has been gaining recognition, and scarce government funds, by applying the pressure exerted on atoms by light to medical and research uses.

Just as computers "that used to be the size of [rooms] can now do a lot of operations faster and cheaper in small components, the same applies to standard chemical and biological processes," says Cordovez. At its University City Science Center home, Optofluidics is building what Cordovez calls a "lab on a chip, in a commercially deployable format that you don't have to be a Ph.D. to use." A user touches Optofluidics' chip to blood drawn with a drugstore lancet, then sticks it "into a reader device. Within an hour you get a reading, a diagnosis, many diagnoses."

The U.S. Defense Advanced Research Products Agency is supporting Optofluidics' work. "When you get bumped in the head, certain proteins" form in response to potential brain injuries, notes Hart. The chip scans for those proteins and makes "a red light/green light diagnosis that can determine if a soldier can stay on the field." Civilian applications include "sports injuries, car injuries, first responders." But those will require Food and Drug Administration approval, which takes years.

Cordovez expects to get next-generation scientific instruments to market quicker. Like a "Star Trek tractor beam," he says, light waves exert pressure on a molecular scale. Using tiny light fibers, "we can use this to trap very small particles" for mass spectrometry and other sophisticated uses — in mini, throwaway versions.

The National Science Foundation has bought in. "We've invested about $650,000 into the team through the Federal Small Business Innovation Research Program," Ben Schrag Ph.D., program director for NSF, told me. Optofluidics is one of a few dozen companies, of 3,000 applicants, funded at that level.

Cordovez and Hart "are world-class experts, but they're also becoming really good entrepreneurs," Schrag said. He praised Optofluidics' intellectual godfather, professor David Erickson at Cornell. "They have a technology here that is really enabling folks to manipulate things at the nanometer scale, which is the Holy Grail. These guys have gone to particles a thousand times smaller" than competing "optical tweezers" and other new technologies.

Contact Joseph N. DiStefano at 215-854-5194, or @PhillyJoeD on Twitter.