As the demand for storage capacity continues to grow at a steady pace as the world creates and stores more and more data, new strategies for preserving information over long periods with reduced energy consumption are needed.
Now, Harvard University researchers have developed a longer-term data storage alternative that uses mixtures of fluorescent dyes to save data files in a cheaper and faster way. Fluorescent dyes are deposited onto an epoxy surface in tiny spots with an inkjet printer. The mixture of dyes at each spot encodes binary information that is read with a fluorescent microscope.
Optical discs, flash drives, and magnetic hard drives can only store digital information for a few decades and require substantial energy to maintain stored information, making these methods not ideal for long-term data storage. Therefore, researchers have been studying the use of different molecules, such as DNA or other polymers, as alternatives to store information at high density and without power, for thousands of years and longer. However, these methods have their own challenges, including high relative costs and slow read/write speeds.
Harvard researchers wanted to develop a molecular strategy that stores information with high density, fast read/write speeds, and acceptable cost. In the experimental system, an inkjet printer is used to deposit tiny spots of the dyes onto an epoxy surface to which they chemically bond, locking information in place. The team chose seven commercially available fluorescent dye molecules that emit light at different wavelengths. The dyes are used as bits of American Standard Code for Information Interchange (ASCII) characters, where each bit is a “0” or “1,” depending on whether a particular dye is absent or present, respectively.
They then used a fluorescence microscope to read the emission spectra of dye molecules at each spot and decode the message. Researchers say the system read the information with 99.6% accuracy, and on a 7.2-by-7.2 millimeter surface, they were able to write 1,407,542 bytes of digital information with the dyes.
Additionally, the fluorescent data could be read 1,000 times without a significant loss in intensity. The system writes information at an average rate of 128 bits per second and reads it at a rate of 469, which is believed to be the fastest reported read speed of any molecular information storage method.
Theoretically, the data can be saved for a very long time – thousands of years or more. According to the researchers, the long timeline of molecular data-storage options is superior to that of current media devices for data storage, which can store information for 40 years at most, have strict size limits, and are susceptible to water damage and hacking. The technique uses no energy once the data is recorded.
As a demonstration, the researchers stored a seminal paper by Michael Faraday, along with a JPEG image of the 19th-century English physicist and chemist. “This method could provide access to archival data storage at a low cost,” said Amit A. Nagarkar, co-lead author of the paper, who conducted the research as a postdoctoral fellow in the Whitesides lab. “[It] provides access to long-term data storage using existing commercial technologies – inkjet printing and fluorescence microscopy.”