Acetylcysteine lysinate

Hydrogen peroxide plays a crucial role in maintaining physiological homeostasis in the human body, so it is imperative to design a highly selective and sensitive fluorescent probe to monitor the content of H₂O₂ in organisms. Herein, we designed a probe with benzothiazole (HBT) as the main fluorophore backbone, which realized the molecular "ESIPT + ICT" synergistic luminescence effect. An effective response to detect H₂O₂ within 30 min was achieved by the probe HBT-B, with a detection limit of 1.73 μM and new peaks are presented after the detection of H₂O₂ in the UV-Vis absorption spectra, with a large Stoke's shift (105 nm). Furthermore, it is demonstrated that the probe HBT-B can be utilized in biological in vivo cellular imaging and has excellent biocompatibility to effectively detect H₂O₂ at the cellular level.

A novel polymeric nanosensor (named PEINAC) based on polyethyleneimine (PEI), was designed for the selective fluorescence detection of l-lysine (L-Lys) in aqueous solutions. The sensor was synthesized through a one-step, three-component reaction involving orthophthalaldehyde (OPA), PEI, and acetylcysteine. This reaction simultaneously facilitated the creation of an isoindole fluorophore, which was chemically attached to the PEI backbone. The structural properties, size, and morphology of PEINAC were thoroughly analyzed using various characterization techniques. When introduced into a buffered solution at pH 7.0, PEINAC demonstrated high specificity for L-Lys, inducing a marked fluorescence enhancement at 450 nm upon excitation at 367 nm. The fluorescence intensity exhibited a linear relationship with L-Lys concentration, ranging from 1 μM to 1000 μM, with a detection limit of 0.13 μM. Notably, the sensor exhibited excellent selectivity, showing no significant interference from other biomolecules and common transition metal ions and anions. This sensor was successfully applied for L-Lys quantification in blood and urine samples and for cellular L-Lys imaging, demonstrating its potential in various analytical and biomedical applications.