The moleculator gets a keypad lock

For your information, a moleculator is simply a molecular scale calculator, or a molecular system which can perform logic and arithmetic operations. Now, LiveScience reports in a brief article that chemists at the Weizmann Institute of Science in Israel have developed a molecule-size keypad lock. This lock is based on a concept similar to the familiar ATM banking machines. But in theory, it could accept lots of different inputs -- or passwords. So the researchers think that this molecular keypad lock could be used for many applications, including saving our secret information.

For your information, a moleculator is simply a molecular scale calculator, or a molecular system which can perform logic and arithmetic operations. Now, LiveScience reports in a brief article that chemists at the Weizmann Institute of Science in Israel have developed a molecule-size keypad lock. This lock is based on a concept similar to the familiar ATM banking machines. But in theory, it could accept lots of different inputs -- or passwords. So the researchers think that this molecular keypad lock could be used for many applications, including saving our secret information.

Here is the introduction of the short LiveScience article.

Organic chemist Abraham Shanzer and his colleagues at the Weizmann Institute of Science in Rehovat, Israel, began with a molecule named FLIP. At its core is a component dubbed a "linker" that mimics a bacterial compound that binds to iron. Attached to it are two molecules that respectively can glow either blue or green.

Here is how this lock works.

There are essentially three "buttons" that scientists can use with this molecular keypad lock. These are an acidic molecule, an alkaline compound, and ultraviolet light.
When the lock is exposed to one sequence of chemicals and light -- the alkaline molecule, followed by ultraviolet light -- it will emit blue light. When the lock is given another "password" -- the acid, then the alkaline, and finally ultraviolet light -- it will glow green.

Below is a diagram showing how the molecular keypad lock works (Credit: Weizmann Institute of Science, via the Journal of the American Chemical Society).

How the molecular keypad lock works

This research work has been published by the Journal of the American Chemical Society under the title "A Molecular Keypad Lock: A Photochemical Device Capable of Authorizing Password Entries" (published online on December 19, 2006).Here is a current link to the abstract, but here is an alternative link for the future. Here are some excerpts.

By harnessing the principles of molecular Boolean logic, we have designed a molecular device that mimics the operation of an electronic keypad lock, e.g., a common security circuit used for numerous applications, in which access to an object or data is to be restricted to a limited number of persons. What distinguishes this lock from a simple molecular logic gate is the fact that its output signals are dependent not only on the proper combination of the inputs but also on the correct order by which these inputs are introduced.
In other words, one needs to know the exact passwords that open this lock. The different password entries are coded by a combination of two chemical and one optical input signals, which can activate, separately, blue or green fluorescence output channels from pyrene or fluorescein fluorophores. The information in each channel is a single-bit light output signal that can be used to authorize a user, to verify authentication of a product, or to initiate a higher process.
This development not only opens the way for a new class of molecular decision-making devices but also adds a new dimension of protection to existing defense technologies, such as cryptography and steganography, previously achieved with molecules.

Abraham Shanzer is working on this kind of moleculator for a number of years. And if you're interested in this subject, you should read another paper published recently by the Journal of the American Chemical Society, "A Molecular Full-Adder and Full-Subtractor, an Additional Step toward a Moleculator" (Vol. 128, No. 14, Pages 4865-4871, April 12, 2006). Here is a link to the abstract.

Over the past decade, there has been remarkable progress in the development of molecular logic and arithmetic systems, which has brought chemists closer to the realization of a molecular scale calculator (a Moleculator). This paper describes a significant step in this direction. By integrating past and new approaches for molecular logic reconfiguration, we were able to load advanced arithmetic calculations onto a single molecular species.
Exchanging chemical inputs, monitoring at several wavelengths simultaneously, as well as using negative logic for the transmittance mode significantly increase the input and output information channels of the processing molecule. Changing the initial state of the processor is an additional approach used for altering the logical output of the device.

Even if the researchers write that their new keypad lock might offer "a new dimension of protection to existing defense technologies, such as cryptography and steganography," I don't see practical applications coming before several years.

Sources: Charles Q. Choi, Special to LiveScience, December 26, 2006; and various websites

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