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SUPRAMOLECULAR LIGHT-DRIVEN
MACHINERY INSPIRED BY FISH
An international team of chemists including Lead author, Professor Rafal Klajn, explains:
members of the Weizmann Institute and
“ Some deep-sea fish have evolved antenna-
Tampere University, have developed a
like molecules capable of absorbing photons in
bioinspired supramolecular concept that
the red wavelength range, whose abundance
could pave the way for the development of
at great depths is close to zero. After absorbing
supramolecular light-driven machines.
a photon, this antenna molecule transfers its
The method deployed transforms energy to the nearby retinal molecule, thus
photoswitchable molecules from their stable inducing its conformational change from the
state to a metastable one using low-energy red cis to trans-retinal. In synthetic systems, such a
light. This has enabled the creation of rapid, highly process would enable using low-energy light for
selective and efficient switching, with potential applications in, for instance, energy storage or
applications envisaged in energy storage, controlled drug release”.
light-activated drug activation and sensing
Dr. Nikita Durandin from Tampere University further
technologies.
explains:
The inspiration came from a natural vision system
“ A common problem for azobenzenes
that has evolved over millions of years which uses
is that they cannot efficiently undergo
supramolecular chemistry to make vision sensitive
photoswitching from the stable transform to
across the visible spectrum. A visual pigment,
the metastable cis form upon low-energy
known as cis-retinal, changes shape when it
red and near-infrared light, the process has
captures photons, and this change leads to
to be driven by UV light. This substantially
corresponding alterations in the supramolecular
limits their applications in fields such as
arrangement of the surrounding proteins, leading
photocatalysis or photopharmacology. Now,
to a cascade of chemical signals that result in
using the supramolecular caging approach
visual perception by the brain.
we can reach almost quantitative trans-to-
This observation led the researchers to consider cis isomerisation with any colour of the visible
the development of a supramolecular machine range”.
that converts azobenzenes, commonly used
Dr. Tero-Petri Ruoko, an expert in ultrafast
synthetic photoswitchable molecules, from
spectroscopy, adds:
stable to metastable states by using virtually
any visible light wavelength. A metallic organic “ Time-resolved spectroscopic studies
cage encloses an azobenzene molecule and a done at Tampere University revealed that
light-absorbing antenna molecule, known as the photochemical processes triggering
a sensitiser. This environment has been found the isomerisation happen superfast, in the
to make certain chemical reactions, which are nanosecond range. In other words, almost one
otherwise impossible, able to take place. billion times faster than the blink of your eyes.”.
[ Reference: Fowle, H., ‘A Dive into Deep-sea Fish-
inspired Supramolecular Light-driven Machinery’,
Electronic Specifier, 20th. November 2023 ]
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