The rapid quantification of hydroxyl radical (·OH) in real samples is a great challenge due to its highly reactive nature and the potential interferences from other coexisting reactive oxygen species (ROS). Herein, a chemiluminescence (CL) probe (ox-CDs) was rationally developed for the detection of ·OH through controlled oxidation treatment of original CDs (o-CDs) with H₂O₂. Post-oxidation of CDs can reduce the surface defects or functional groups on the CDs, exposing reactive sites capable of effectively reacting with ·OH. The chemical energy generated from redox reaction between ·OH and the ox-CDs can be efficiently utilized to generate strong and selective CL responses to ·OH without interferences from other ROS. Thus, a highly selective and sensitive CL method with a linear range from 0.01 to 150 µM and a detection limit of 3 nM was developed, which was successfully applied for monitoring the ·OH production from cigarette and mosquito coil smoke.

As a new type of fluorescent nanomaterials, carbon dots (CDs) have exhibited excellent photoluminescence properties with tunable emission and high quantum yields, hence they have attracted an increasing interest in diverse research areas. The photoluminescence performance of CDs is primarily influenced by their precursors, which directly or indirectly determine the structures and specific functions of the resultant CDs. In this review, we aim to summarize the recent progress on synthesis of CDs using small aliphatic molecules, anilines, polyphenol, polycyclic aromatic hydrocarbons, organic dyes, or biomass as precursors. The associations of the physical and chemical properties of the CDs with their respective precursors are comprehensively investigated, and the potential applications and future development of CDs are discussed in detail. It is hoped that this review will open new horizons for CDs preparation by rational selection of the precursors from the vastly available carbon sources and the critical comments presented, here could inspire and guide future research in the design of multifunctional CDs.

Temperature measurement in biology and medical diagnostics, along with sensitive temperature probing in living cells, is of great importance; however, it still faces significant challenges. Metal nanoclusters (NCs) with attractive luminescent properties may be promising candidates to overcome such challenges. Here, a novel one-step synthetic method is presented to prepare highly fluorescent copper NCs (CuNCs) in ambient conditions by using glutathione (GSH) as both the reducing agent and the protective layer preventing the aggregation of the as-formed NCs. The resultant CuNCs, with an average diameter of 2.3 nm, contain 1-3 atoms and exhibit red fluorescence (λ_em = 610 nm) with high quantum yields (QYs, up to 5.0%). Interestingly, the fluorescence signal of the CuNCs is reversibly responsive to the environmental temperature in the range of 15-80 ℃. Furthermore, as the CuNCs exhibit good biocompatibility, they can pervade the MC3T3-E1 cells and enable measurements over the physiological temperature range of 15-45 ℃ with the use of the confocal fluorescence imaging method. In view of the facile synthesis method and attractive fluorescence properties, the as-prepared CuNCs may be used as photoluminescence thermometers and biosensors.