Unravelling structural insights into ligand-induced photoluminescence mechanisms of sulfur dots.

Sulfur dots (S-QDs) hold promise as a new category of metal-free, luminescent nanomaterials, yet their practical application faces challenges primarily due to a limited understanding of their structure and its impact on their optical properties. Herein, by employing a spectrum of aliphatic and aromatic ligands, we identify the surface structure and composition of S-QDs while delineating the pivotal role of ligands in inducing photoluminescence. Thiol-functionalized ligands, such as 4-mercapto benzoic acid and glutathione, notably promote the formation of both green and blue luminescent S-QDs, boosting a high quantum yield of up to 56%.

Use of Single-Molecule Plasmon-Enhanced Fluorescence to Investigate Ligand Binding to G-Quadruplex DNA.

Single-molecule measurements are crucial for studying the interactions between G-quadruplex (GQ) DNA and ligands, as they provide higher resolution and sensitivity compared to those of bulk measurements. In this study, we employed plasmon-enhanced fluorescence to investigate the real-time interaction between the cationic porphyrin ligand TmPyP4 and different topologies of telomeric GQ DNA at the single-molecule level. By analyzing the time traces of the fluorescence bursts, we extracted dwell times for the ligand.