Close-up of Graphene Frontier's sensor chips on a silicon wafer. Image: Graphene Frontiers
Getting a physical is a pain. Wouldn't it be nicer if you didn't have to give up two vials of blood and wait a few weeks to find out if there's something horribly wrong with your body? What if instead you could run 100 tests with just a single drop of blood?That's the (admittedly long-tail) goal of Graphene Frontiers, a Philadelphia-based company that has developed nanoscale sensors using single-atom-thick graphene sheets. The end result is biosensors that can individually detect key markers like cardiac stress proteins, and which are small enough to be combined into diagnostic chips that could perform dozens of tests at once.
"Even with [the current] dime-sized chip, we could have 100 different sensors," said Graphene Frontiers CEO Mike Patterson. "Whatever we stick to that channel determines what kind of sensor that is. So we could do 100 different antibodies, [though] we'd probably do 25 tests in four rows, for statistical value."The premise is fairly simple, in theory. Each sensor consists of a pair of electrodes connected by a graphene channel on a silicon substrate, like a basic electrical circuit.
To turn it into a specific sensor, Graphene Frontiers attaches an antibody for, say, cardiac troponin, a biomarker of cardiac stress levels in the blood. If cardiac troponin is present, it sticks to the antibody, producing an immediate and measurable fluctuation in the tiny current flowing through the sensor. Bingo, bango: You've got a positive hit.It's not an entirely new concept, as similar sensors have been developed using silicon. But the promise of graphene is that it's as thin of a base as you can get, it's a highly conductive material, and false positive-inducing foreign objects have a hard time sticking to it. This means tests will be quick and accurate, when and if Graphene Frontier's sensors go commercial.And that's a big if, right? I mean, we are talking about graphene here, one of the most hyped materials in the last decade. Patterson was careful to temper the excitement, but he's confident in the concept.
"For about 10 years, it's been on the horizon," Patterson said. "I'm hopeful that this will be the big breakthrough application. But what we've chosen is still hard. We're a couple years from seeing it in an actual device."
Actually manufacturing the sensors isn't as complicated as you may think, at least once a method for creating sheets of graphene and transferring them to a silicon wafer has been developed. Graphene Frontiers has exactly that; it's a patent that Patterson said has been very valuable to the company."Admittedly, this device, with the exception of the graphene, is fairly basic," he said. "People have been doing this for a long time, but the graphene is a special sauce.""The beauty is that it's all scaleable, which is why it hopefully will be successful," he added. "With one wafer, we could make hundreds of these sensors."Patterson said that, currently, each sensor costs the company about $10 to manufacture, and that at scale, that cost could drop to pennies. He added that the big obstacle isn't manufacturing, but showing that the sensors can produce accurate enough results to be reliably used in medical applications."The challenge with a lot of these sensors is not always sensitivity, because there are a lot of things out there that are very sensitive," he said. "It's the selectivity, making sure we don't get a false positive."But while medical diagnostics are an immediate, obvious use of the tech—and seriously, who wouldn't want to test themselves for a couple dozen medical issues in minutes?—the sensors also have potential for use as environmental monitors. By attaching custom-built DNA strands to their sensors, Patterson said the company can scan for a variety of volatile organic compounds.In the promo video above, for example, the company suggests its sensors could mimic the noses of drug- and bomb-sniffing dogs, monitoring for contraband in a persistent, ambient fashion. Imagine filling an airport with low-powered sensors that automatically sound the alert when cocaine molecules float by. The TSA would buy them in a heartbeat.Again, this is a few years off at least, and that's assuming the company can keep enough cash flow moving to get there. (Currently, Graphene Frontiers is working with a few medical research concerns and looking for more research support from larger companies.) Regardless, the tech has the right mix of tantalizing and straightforward attributes to make it seem likely that someone's going to mass produce it, especially with the growing emphasis on quantifying everything.