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Published online: 9 July 2008 | doi:10.1038/nchina.2008.156

Molecular devices: Secured login

Felix Cheung

Introduction

© (2008) Wiley Interscience

In 2007, scientists in Israel¹ made a molecule named FLIP that mimics the function of an electronic keypad lock. The fluorescence of FLIP is activated only when the correct 'password' — the proper input sequence of chemicals and light — is supplied. The technology could safeguard molecular devices from illegal access, but is incapable of authorizing user-specific functionalities. Chunhua Yan and co-workers at Peking University in Beijing² have made a molecule named MPTEA that can do both — mimicking the login step of computer software.

The molecule MPTEA is organic and fluorescent. Password entry is done through the input of chemicals (a choice of three), ultraviolet light and quenchers, which can change the emission wavelength and intensity of MPTEA. There are thousands of possible input sequences, but only one unique sequence can make MPTEA produce bright emission at a wavelength of 500 nm (or 435 nm), thereby passing the authorization for user 1 (or user 2). Any other sequence will produce relatively little or no emission, thereby failing the authorization.

The activated MPTEA can then be used as a chemically driven platform for computing binary arithmetic (pictured), such as the addition and subtraction of emission signals. The platform is user specific; a user who is endowed with the addition functionality cannot access the subtraction functionality of the other user.

The emission signals can be further encrypted by introducing a sequence of chemicals or light to the activated MPTEA. Only users who know this sequence can decrypt the signals.

The authors of this work are from:
Beijing National Laboratory for Molecular Sciences, State Key Laboratory of Rare Earth Materials, Chemistry and Applications and PKU–HKU Joint Lab in Rare Earth Materials and Bioinorganic Chemistry, Peking University, Beijing, China.

References

1. Margulies, D., Felder, C. E., Melman, F. & Shanzer, A. A molecular keypad lock: A photochemical device capable of authorizing password entries. J. Am. Chem. Soc. 129, 347–354 (2007).  | Article | ChemPort |
2. Sun, W. et al. A fluorescent-switch-based computing platform in defending information risk. Chem. Eur. J. doi: 10.1002/chem.200800576 (2008).  | Article |