PROTEIN MEMORY FOR COMPUTERS
Akshata.s.revankar
E&C,8thsem
Usn:2mm7ec002
Email:
Abstract:
While magnetic and semi-conductor based information storage devices have been in use since the middle 1950's, today's computers and volumes of information require increasingly more efficient and faster methods of storing data. While the speed of integrated circuit random access memory (RAM) has increased steadily over the past ten to fifteen years, the limits of these systems are rapidly approaching. In response to the rapidly changing face of computing and demand for physically smaller, greater capacity, bandwidth, a number of alternative methods to integrated circuit information storage have surfaced recently. Among the most promising of the new alternatives are photopolymer-based devices, holographic optical memory storage devices, and protein-based optical memory storage using rhodopsin , photosynthetic reaction centers, cytochrome c, photosystems I and II, phycobiliproteins, and phytochrome.
Introduction:
This seminar focuses mainly on protein-based optical memory storage using the photosensitive protein bacteriorhodopsin with the two-photon method of exciting the molecules. Bacteriorhodopsin is a light-harvesting protein from bacteria that live in salt marshes that has shown some promise as feasible optical data storage. The current work is to hybridize this biological molecule with the solid state components of a typical computer.
In response to the demand for faster, more compact, and more affordable memory storage devices, several viable alternatives have appeared in recent years. Among the most promising approaches include memory storage using holography, polymer-based memory, and our focus, protein-based memory.
What is protein memory?
Several biological molecules are being considered for use in computers, but the bacterial protein-Bacteriorhodopsin (bR)-has generated much interest among scientists. In the past few decades, much research was carried out in several laboratories in North America, Europe, and Japan, and the scientists become successful in building prototype parallel processing devices, three-dimensional memories, and protein-based neural networks.
Bacteriorhodopsin, a light harvesting bacterial protein, is the basic unit of protein memory and is the key protein in halo bacterial photosynthesis. It functions like a light-driven photo pump. Under exposure to light it transports photons from the hollow bacterial cell to another medium, changes its mode of operation from photosynthesis to respiration, and converts light energy to chemical energy thus can be utilized to frame protein memories.
ENERGY PATTERN
Protein Memory Chip
Advantages:
14. Advantages and Applications of
Bacteriorhodopsin
Bacteriorhodopsin is an excellent molecule for photonics. Naturally occurring, the purple pigment grows in salt marshes and has evolved to exist in half-a-dozen stable states within a convenient, reversible photo cycle. This robust system, coupled with the emergence of genetic engineering, forms the basis of a variety of applications and devices based on bacteriorhodopsin that are now beginning to emerge.
The range of potential applications for which bacteriorhodopsin (bR) has been
Investigated is remarkable. It includes:
1) Reversible holographic memory
2) Ultrafast random-access memory
3) Neural logic gates
4) Spatial light modulation
5) Nonlinear optical filters
6) Photonic-crystal band gap materials,
7) Pattern-recognition systems
8) High-contrast displays
9) Optical switches
10) Pico second photo detectors.
Unlike many other biomolecules, which are too unstable to be used in any commercial device, bR is protected against photo-induced breakdown - which is caused by reactive oxygen, singlet oxygen and free radicals - by its structure.
15. Conclusion
Bacteriorhodopsin has attracted the attention of scientists interested in using biological materials to perform technological functions. Part of the attraction of natural materials is that they often perform very complex functions that cannot be easily synthesized. Evolution has perfected these functions over billions of years, often performing better than human-designed materials ever could.
In the last 25 years, bacteriorhodopsin has excited a great deal of interest among biochemists, biophysicists, and most recently among companies seeking to build battery conserving, long-life computer displays. If controllable, quick-change proteins like bacteriorhodopsin could also be used in a kind of electronic writing.
In addition, the protein's photoelectric properties could be used to manufacture Photo detectors. Bacteriorhodopsin is also an attractive material for all-optical 'light' computers because of its two stable protein forms, one purple and one yellow. Shining two lasers of different wavelengths alternately on the protein flips it back and forth between the two colors. Several research groups have already used bacteriorhodopsin as computer memory and as the light-sensitive element in artificial retinas.
With fast random access capability, good reliability, and transportability protein memories enhance the multimedia capabilities of computers to a great extent. Also, the advantages of optical data storage accrue to such memories. Enormous access to information and manipulation and storage of data in minimal time add to their reliability. Unlike disk memories where physical contact with the magnetic head is required to Read/Write information, protein memories use laser beams, which improves their life with reduction in wear and tear.
Researchers are now closely following the way human brain stores, retrieves, and acts on information, to build a biological computer. They are trying to duplicate the capability of information retrieval by inputting a part of it, or any related aspect, instead of specifying the address of the memory location. Though a group of researchers headed by Robert Birge of Suracuse University, USA, has succeeded in developing similar ones, much work is still required to make a fully operational computer with memory that mimics human brain.
Indeed, we are on the threshold of new and exciting era in the wonderful world of computing. And every possibility is there that in the near future we will be able to carry a small encyclopedic cube containing all the information we need
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