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Posted: January 25, 2009
Hydrogen bonding instrumental in self-organizing complex nanostructures
(Nanowerk News) Nicola Armaroli and co-workers from CNR-ISOF, Bologna, Italy, and Davide Bonifazi and colleagues from the Università di Trieste, Italy, and the University of Namur, Belgium, have shown that pi-conjugated molecules bearing complementary hydrogen bonding sites can self-organise into complex nanostructures, which resemble natural micellar systems ("Engineering spherical nanostructures through hydrogen bonds" – free access article).
Chromophoric acetylenic scaffolds bearing complementary uracyl and 2,6-di(acetylamino)pyridyl moieties undergo supramolecular recognition and generate uniform nanoparticles
Nature creates spectacular nanoarchitectures through specific supramolecular assemblies of various components. Complementary hydrogen bonds are often utilised, which leads to the optimization of solvophilic interactions.
The use of hydrogen bonding also enables the tuning of the size and shape of the nanoparticles. The complementary hydrogen bonds promote self-organisation of the nanoparticles into uniform aggregates, and also enable a morphological change to occur from nanoparticle to vesicles.
Armaroli has also shown that the nanoaggregation can be reversed with temperature, which suggests possible applications of these vesicles in molecular delivery.
'The ultimate aim of this work is to create a library of nanoarchitectures, which may exhibit potential applications as drug carriers, in biological imaging and in optoelectronic devices,' says Armaroli.
However, Armaroli acknowledges that one of the main challenges to overcome is to design nanostructures with the desired molecular functionality, without compromising key features such as chemical stability and photoluminescence.