Scientists from Kazan Federal University (KFU), together with colleagues from the Kazan Scientific Center of the Russian Academy of Sciences, have obtained new biocompatible luminescent materials based on cyclic dipeptides. In particular, this opens up prospects for the development of targeted drug delivery systems, the university’s press service reported.
Dipeptides are short molecules consisting of two amino acid residues. The scientists focused on two dipeptides: L-alanyl–L-leucine (Ala-Leu) and L-leucyl–L-alanine (Leu-Ala). It was found that when heated above the critical temperature in the solid phase, they transform and form a cyclic dipeptide — a derivative of 2,5-diketopiperazine.
One of the most significant discoveries was the luminescent properties of cyclo(Ala-Leu) microstructures. Experiments have shown that they a 372 nm excitation (absorption) and 460 nm emission (fluorescence) wavelength, with a 40% quantum yield, which is high for such systems. Until now, there have been virtually no examples of luminescence in aliphatic dipeptides in the scientific literature, which confirms the significant potential for the discovery, according to the press service.
Cyclic dipeptides form micro- and nanostructures of various shapes depending on the solvent. In some conditions, thin fibers and fibrils are produced, and flat lamelles in others. Fibrous structures are crucial for creating gel-forming systems in targeted drug delivery. Lamellar formations, in turn, open up prospects for use in optical devices and materials with unique light properties, the university said.
