Excitation-dependent visible fluorescence in decameric nanoparticles with monoacylglycerol cluster chromophores

Abstract

Organic fluorescent nanoparticles, excitation-dependent photoluminescence, hydrogen-bonded clusters and lysobisphosphatidic acid are four interesting individual topics in materials and biological sciences. They have attracted much attention not only because of their unique properties and important applications, but also because the nature of their intriguing phenomena remained unclear. Here we report a new type of organic fluorescent nanoparticles with intense blue and excitation-dependent visible fluorescence in the range of 410–620 nm. The nanoparticles are composed of ten bis(monoacylglycerol)bisphenol-A molecules and the self-assembly occurs only in elevated concentrations of 2-monoacylglycerol via radical-catalysed 3,2-acyl migration from 3-monoacylglycerol in neat conditions. The excitation-dependent fluorescence behaviour is caused by chromophores composed of hydrogen-bonded monoacylglycerol clusters, which are linked by an extensive hydrogen-bonding network between the ester carbonyl groups and the protons of the alcohols with collective proton motion and HO···C=O (n→π*) interactions.

Excitation-dependent fluorescence from atomic/molecular layer deposited sodium-uracil thin films

“…This kind of behaviour is especially pronounced in systems, where the solvation dynamics are slowed down to the same order of magnitude as the fluorescence lifetime of the excited moiety 34 . We suspect that in our samples, the extensive hydrogen-bonding network between the uracil molecules could form such a motionally restricted media to enable favorable conditions for REES 38 . The continuous relaxation model is supported by the TRES analysis that shows a gradual shift toward longer wavelengths with a constant spectral shape and FWHM.…”

“…This effect was originally observed in rigid and viscous media, such as low-temperature glasses and polymer matrices that display only modest excitation-dependent shifts 34 . Furthermore, more recently REES has been observed in self-assembled peptide nucleic acids, in reduced graphene oxide and decameric monoacylglycerol nanoparticles 35 – 38 . These red-edge effects are assumed to result from the distribution of interaction energies between the excited-state fluorophore and the molecular environments, as well as the slowed relaxation/solvation dynamics of the molecular environments.…”

Photoluminescent PEG based comacromers as excitation dependent fluorophores for biomedical applications

“…Similar EDF phenomenon was reported with monoacylglycerol cluster chromophores in which OH…CO (n-π*) interactions between the ester carbonyl groups and protons of the alcohol were responsible factor for exhibiting EDF phenomenon [34]. …”

Advanced glycation end products in hemodialysates as fluorescent and optical absorption markers of patients mortality

“…The nanoparticles approach to investigate the processes in human body is getting stronger. Besides our comparative studies [5,14] there is another attempt to elaborate a nanoparticles biomimetic model solution using monoacylglycerol clusters [21].…”