Biomolecular optical data storage and data encryption

Abstract

The use of bacteriorhodopsin (BR) as an active layer in write-once-read-many optical storage is presented. This novel feature of BR materials may be used on a wide variety of substrates, among them transparent substrates but also paper and plastics. The physical basis of the recording process is polarization-sensitive two-photon absorption. As an example for this new BR application, an identification card equipped with an optical recording strip is presented, which has a capacity of about 1 MB of data. The recording density currently used is 125 kB/cm2, which is far from the optical limits but allows operation with cheap terminals using plastic optics. In the examples given, data are stored in blocks of 10 kB each. A special optical encryption procedure allows the stored data to be protected from unauthorized reading. The molecular basis of this property is again the polarization-sensitive recording mechanism. The unique combination of optical storage, photochromism, and traceability of the BR material is combined on the single-molecule level. BR introduces a new quality of storage capability for applications with increased security and anticounterfeiting requirements.

Molecular Information Technology

“…It is not clear yet whether BR can compete with inorganic and synthetic storage materials, however, memory architectures that exploit BR's photoelectric properties or utilize a larger number of its conformation states could possibly give BR an advantage over conventional materials [155]. The use of BR in optical recording strips on identification cards is also under consideration [173]. The choice of wavelength for the addressing beams determines what state is set in the addressed memory cell.…”

“…The recent availability of semiconductor devices (LEDs) with emission in the near ultra-violet [344] make optical methods increasingly more attractive for interfacing molecular materials with conventional electronic architectures. Many proposed molecular computing devices are not intended to function stand-alone, but as part of a hybrid molecular-conventional computing system, e.g., as a molecular co-processor [345] or a molecular memory [172,346,173].…”

Data storage based on photochromic and photoconvertible fluorescent proteins

“…While research on data storage based on DNA exists (Cox, 2001;Yachie et al, 2007), the use of the photochromic properties of proteins was pioneered with bacteriorhodopsin (bR) (Tallent et al, 1996). The spectral shifts between the different intermediate states of bR, assisted by the fact that the molecule easily forms 2D crystal-like arrangements, made this protein an interesting target to develop a rewritable storage medium (Bae et al, 1999;Fischer et al, 2003;Yao et al, 2005aYao et al, ,2005bOrtiz-Lombardía and Verma, 2006) and led some researchers to propose the design of a biological DVD-like device by spin-coating a disk with bR (Renugopalakrishnan, 2006).…”

All-Optical Switching in Plant Blue Light Photoreceptor Phototropin

“…The photochromic bacteriorhodopsin (bR) protein found in the purple membrane fragments of Halobacterium halobium has by far been the most widely studied biomolecule and a wide range of applications has been proposed due to its unique properties [6]- [19]. A switch is the basic building block of information processing systems.…”

“…A switch is the basic building block of information processing systems. Recently, there has been considerable interest in analyzing all-optical switching with bR [8]- [19]. The switching response in bR is in the ms range, which can prove useful for parallel computing [8]- [19].…”