Neon dyes compete with DNA to be world's next data encryptor

Harvard researchers are working on a colorful way of storing digital information -- mixtures of fluorescent dyes. These liquids, they believe, could replace the bulky, hackable, energy-burning magnetic tapes we still use to hold invaluable data. 

Yes, for long-term data storage we still invoke tapes reminiscent of the music cassettes and VHS movies likely stocked somewhere in your basement. But while these tapes are effective, they take up lots of physical space, pose security risks, consume a fair amount of energy, are expensive to maintain and only remain viable for about 20 years. 

"The amount of energy that's required to maintain the facilities in which the information is stored is pretty high -- and getting higher," said George Whitesides, a professor in the Department of Chemistry at Harvard University and lead author of research published Wednesday by the American Chemical Society. 

That's why his team looked to fluorescent mixtures. Whitesides arrived at the unique idea by first posing a question: "How do you store information in such a way that it's simple to do, but has the characteristic that it minimizes the energy required to keep it stored and does not require vast amounts of new technology to make it work?"

He says his invention uses commercially available, relatively inexpensive materials and "doesn't require any energy once you've written the message, picture, whatever it is."

As proof of principle, Whitesides and his team encoded an iconic research paper written by Michael Faraday with their neon dye concoctions. They selected seven store-bought fluorescent molecules, created various mixtures that stood in for sequences of computer language, or bits, and used an ink-jet printer to permanently dot the mixtures onto a small section of an already tiny slide. 

Basically, they condensed 14,075 bytes of data -- 112,600 bits -- to around a 2-inch (52 millimeter) area. If magnetic tape had been used, the information would have taken up approximately 2.34 inches (59 millimeters) of a strip. Though the difference seems small when isolated, that extra space, when compounded, could free up a ton of room in storage facilities.

From there, the team read the information they'd printed with a fluorescence microscope, a tool commonly used by chemists. Turns out, Faraday's paper was perfectly encoded and the microscope read the fluorescent data over 1,000 times with no significant loss of information. Plus, as the data is permanently fused to the surface, it would probably be pretty hard to hack and the researchers believe it may not call for highly expensive maintenance measures in the future.

Of course, you're probably wondering if you couldn't just store the data on a USB. What about "the cloud" and SSD hard drives? Sure, but those devices are prone to water damage or may degrade over time, among other potential pitfalls. Unlike our day-to-day digital data, things that require super long storage aren't -- and shouldn't be -- kept in such a way. 

"That can range anywhere from patient records and dealing with medical data to things that are baby pictures," Whitesides said. 

A closer look at fluorescent binary code

Each of Whitesides' seven liquids comprise a different molecule that emits a wavelength corresponding to its color. These molecules can rapidly be read by a fluorescence microscope. The entire fascinating operation is rooted in how humans communicate with computers.

Let's take a step back. In computer language, information is stored in bits of 0's and 1's. Words can be formed with specific sequences of those bits, such as "0101," and long combinations of such sequences form sentences -- and all of that is binary code. Typically, uncompressed bits are written onto magnetic tapes as you'd expect, kind of like writing words on many, many pieces of paper.

"Magnetic tape, you have a specific device which is a magnetic tape writer [and] reader," Whitesides said. "And that is a device, which you use in computing, in collaboration with your computer or whatever storage system you have."

But in contrast to magnetic tape's old-fashioned structure, one dot of the team's novel mixtures can represent a bunch of bits at the same time.

Let's assume we're making a mixture for a three-digit sequence. We have the colors pink for space 1, green for space 2 and blue for space 3. Presence of these colors means a bit of "1" and absence means a bit of  "0." 

If the mixture has only pink, that means it represents a sequence of "100."

"You can make any combination of 1 and 0 in these three spaces that you have set up for the word that you're working with," Whitesides said. "Each spot can represent a sequence."

He added, "if you can represent 1s and 0s just by mixing [dyes], you'll see how you can then go from there to binary code -- and binary code enables you to replicate text ... or replicate pictures."

Presently, Whitesides is attempting to deduce the number of neon dots that can be placed onto a slide before the microscope can't detect compositions anymore. That way, he can figure out exactly how much compression can be done of the binary code to limit taking up as much physical space as possible. 

Next steps, he says, include learning the best way to store the slides -- hopefully, one that doesn't need too much energy.

Whitesides isn't the only one working on molecular methods of storing digital data. A very popular sector right now is DNA-inspired data storage. But "the synthesis of long strands of DNA, which is what's required to make a storage medium that's like DNA is actually a fairly intensive activity," he said. 

Regardless, Whiteside's fluorescent dye method, the researchers say, interprets information at a faster rate than any current molecular storage device, including DNA.

"But they're all interesting and this issue of storage of information is something which is just beginning," he said. "We'll have to see what happens over the next couple of years."