Two-Emission Channel Hybrid Nanosensors Based on BODIPY-Appended Nanocrystalline Cellulose for Determination of Biothiols

The amounts of cysteine (Cys), homocysteine (Hcy), and glutathione (GSH), which are biothiols that have an important role in biological organisms in living systems, are associated with many diseases or dysfunctions. In this study, hybrid nanosensors based on the boron-dipyrromethene (BODIPY)-appended nanocrystalline cellulose (NCC) platform with two emission channels (3, 4) have been designed and applied to determine biothiols in the real sample for the first time. The chemical and morphological characterizations of the prepared compounds (mono-(1), distyryl-BODIPY (2)) and target NCC-based fluorescence hybrid materials (3, 4)) were performed, and the optimum conditions for the detection procedures of biothiols were determined. After treatment with biothiols, an intramolecular rearrangement reaction resulted in the removal of 4-chloro-7-nitrobenzofurazan (NBD) from the structure and the fluorophores mono- and distyryl-BODIPYs were released in the nanostructures simultaneously. Moreover, the nanosensor systems cause an increase in sensitivity and selectivity through the increased surface area and the presence of an increased number of binding sites due to the surface-modified NBD-based fluorophore groups. The two emission channels with various response ratios 3 and 4 were used as analytical signals for distinguishing GSH, Cys, and Hcy. The detection limits for biothiols were determined between 5.0 and 90.0 nmol L–1 with wide linear working ranges for 3 and 4 within a few seconds. The accuracy of the determination methods presented based on 3 and 4 was evaluated using a spike/recovery test and high-performance liquid chromatography (HPLC). After assessing the accuracies of 3 and 4, discriminative determination of trace levels of Hcy, Cys, and GSH was successfully carried out in a simulated human serum sample. Importantly, RGB-based practical applications of hybrid nanosensors (3 and 4) were competently utilized by fabricated paper-based detection kits for biothiols.