Aggregation-induced emission enhancement (AIEE) of gold nanoclusters in biopolymer hydrogel nanoparticles
Daniil S. Chumakov 1, Stella S. Evstigneeva 2,3, Andrey M. Burov 1, Nikolai G. Khlebtsov 1
1. Institute of Biochemistry and Physiology of Plants and Microorganisms, Saratov Scientific Centre of the Russian Academy of Sciences (IBPPM RAS), Saratov, Russia
2. Saratov State University, Saratov, Russia
3. Saratov State Medical University of V.I. Razumovsky, Ministry of Health of the Russian Federation, Saratov, Russia
Abstract
Gold nanoclusters have considerable potential in the field of imaging. They are characterized by simple synthesis, a large Stokes shift, and high photostability. One challenge associated with their biomedical application is the low fluorescence quantum yield of most gold nanoclusters. Functionalizing them with targeting biomolecules also presents some difficulty. Encapsulating nanoclusters in polymer scaffolds can restrict the intramolecular mobility of the surface ligands of AuNCs. This also significantly increases their fluorescence intensity through the aggregation-induced emission enhancement effect (AIEE effect). In this work, we used the spatial confinement method to obtain hydrogel nanoparticles impregnated with glutathione-stabilized gold nanoclusters. Chitosans (CS) of different molecular weights served as polymer matrices: 15 kDa (low molecular weight), 38 kDa (medium molecular weight), and 200 kDa (high molecular weight). The nanocomplexes formed predominantly through strong Coulomb interactions between the amino groups of chitosan and the carboxyl groups of the thiolate ligands. The hydrogel nanoparticles were characterized by spectrofluorimetry, TEM, DLS, and zeta potential measurements. The dependence of fluorescence enhancement on concentration was established for chitosans of different molecular weights. The stability of the CS-GSH-AuNCs nanocomplexes was studied over a wide pH range. Additionally, we formed a pectin corona on the surface of the hydrogel nanoparticles to modulate fluorescence. The most pronounced AIEE effect was observed for CS-GSH-AuNCs nanocomplexes based on high-molecular-weight 200 kDa CS. Given their high biocompatibility, intense fluorescence, and ease of functionalization, these nanoplatforms appear promising for bioimaging.
This research was funded by the Russian Science Foundation (grant No. 26-74-10068).
Speaker
Daniil S. Chumakov
Institute of Biochemistry and Physiology of Plants and Microorganisms, Saratov Scientific Centre of the Russian Academy of Sciences (IBPPM RAS), Saratov, Russia
Russia
Discussion
Ask question
