Contents









Overview
History of protein memory
RAM Types
Protein Memory
Data Write, Read & Erase techniques
Practical Memory Cell
Protein memory vs conventional RAM
Applications
Present status
Overview
•Protein memory is an experimental means of storing
data.
•Using proteins ,that respond to light from bacteria
found in salt water, a small cube can store large
amounts of data.
•By using lasers, the protein can be changed depending
on various wave lengths, allowing them to store and
recall data. As a result protein can be used to store
enormous amounts of data using lasers to read and
write binary code.
History of protein memory
 Protein memory was discovered by Walther Stoeckenius
and Dieter Oesterhelt at Rockefeller University in New
York.
 They discovered that a protein isolated from a salt marsh
bacterium exhibited photosensitive properties. They called
this protein bacteriorhodopsin ,because it was very
similar to the protein, rhodopsin that founds in the eyes of
humans and animals.
RAM Types
 DRAM (Dynamic RAM)
 SRAM (Static RAM)
DRAM (Dynamic RAM)

Must be refreshed every few millisecond

Cheaper and widely used

Low power consumption
SRAM (Static RAM)

Faster than DRAM

Costly
Protein memory
How Protein Memory compete with electronic
memory?
 Speed
 Reliability
 Capability
 Cost
Basic unit of Protein Memory
Bacterial protein molecule - Bacteriorhodopsin (bR)
Bacteriorhodopsin ( bR )
 Purple membranes of Halo bacterium halobium.
 Changes mode of operation upon light incident.
 Light energy to chemical energy conversion.
Why bR?
 bR grows in salt marshals
 Where temp can exceed 150 degree Farad for extended
time period
 Salt concentration in aprx 6 times that of sea water
 Survival indicates its resistance to thermal and
photochemical damages
 Excellent optical characteristics & Long term stability
Photo cycle of Bacteriorhodopsin
Chromophore – Light absorbing component
Light energy triggers a series of complex internal
structural changes - Photocycle
Photo cycle of Bacteriorhodopsin
Molecular Structure
 Quite similar to ‘Rhodopsin’, the light detecting
pigment in retinas of human eye
Data Writing technique Photo cycle
Data Reading technique Photo cycle
Data Erasing Technique
 Blue laser erases encoded data
 Q state absorb blue light and return to original bR
state
 Individual data can be erased using blue laser
bR Memory Cell by Bob Birge
 - Implemented a prototype memory
 - bR molecules to store digital bits
Birge’s Memory Cell
 Stores data with 10,000 molecules per bit
 Molecule switches in 500 femtoseconds
 Speed only limited by laser steering speed
 Estimated that Data stored live around 5 years
without any refreshment
Birge’s Memory Cell
VS
Conventional Electronic RAM
Data access

300 times faster than conventional RAM
Storage Capacity
 4096 x 4096 bits page
 16 Mb per page
 1000 such pages
 16 Gb total capacity
Birge’s Memory Cell
VS
Conventional Electronic RAM
Data Stability
 Data is highly stable
 Even the power is off, memory retain its information
 Energy efficient computer that can be switched
on/off instantly
 No waste of booting time
Birge’s Memory Cell
VS
Conventional Electronic RAM
 Transportation
 Can remove small data cubes and ship gigabytes of data
 No moving parts – safer than small hard drives
 Can operate in wider range of temperatures
Birge’s Memory Cell
VS
Conventional Electronic RAM
 Cost
 bR protein can be produced in large volumes at low price
 Birge’s memory cell costs 2 US $ and can store 7 Gb.
Applications of bR
 Ultra fast RAM
 Finger print processing
 Optical switches
 Neural Logic gates (genetic engineering)
Present Status
 Not used for commercial applications.
 Used for military and scientific applications..
 Researches are going on for….
 High speed high capacity memory for commercial
applications
 Ultimate machine intelligence with the aid of genetic
engineering (A memory that mimics human brain).
 Carry a small encyclopedic cube containing all the
information we need !!.
Conclusion
 During the past decade, the speed of computer processors
increased almost 1,000 times, where as data storage
capacities increased only by a factor of 50. Also, the transfer
of data within the computer remains the principal
bottleneck that limits performance.
 Protein memories use laser beam, which improve their life
with reduction in wear and tear.
THANK YOU