Pulsed laser fragmentation synthesis of carbon quantum dots (CQDs) as fluorescent probes in non-enzymatic glucose detection

[Display omitted] •Fluorescent carbon quantum dots (CQDs) were fabricated via pulsed laser fragmentation in liquid (PLFL).•Further treatment of CQDs through PLFL with an oxidizing agent enhanced their water solubility.•The functionalization of oxidized CQDs with boronic acid (CQDs-APBA) increased their fluorescence emission.•The CQDs-APBA exhibited a fluorescence-off response to glucose at increasing concentrations. Pulsed laser fragmentation in liquid (PLFL) is one of the synthesis routes for producing high-purity carbon quantum dots (CQDs) with less toxic by-products in a straightforward system. The limited literature regarding the application of PLFL-synthesized CQDs motivated this study to exploit them as fluorescent probes in glucose sensing. The design of a fluorescent-based non-enzymatic glucose sensor was achieved by implementing CQDs and 3-aminophenylboronic acid (APBA) as fluorescent probes and glucose receptors, respectively. The CQDs were fabricated by PLFL through an Nd:YAG nanosecond laser, starting from the carbon powder dispersion in ethanol. Then, a laser-assisted post-modification process with oxidizing acid was implemented to produce water-dispersible CQDs for easy functionalization. Functionalizing these CQDs with APBA (CQDs-APBA) resulted in a blue-shifted fluorescence emission with a 35% quantum yield and high photostability. The CQDs-APBA exhibited a turn-off response at increasing glucose concentrations. This method offers good sensitivity with a linear detection range of glucose with a concentration of 0.165 to 8 mM and a detection limit of 165 µM. The applicability of this sensor to real analytes such as saliva obtained a satisfactory result with good reproducibility. This work proves that CQDs synthesized from PLFL can also be an alternative fluorescent probe for fluorescent-based sensing applications.