Cascade Detection of Pyridoxal 5′-Phosphate and Al³⁺ Ions Based on Dual-Functionalized Red-Emitting Copper Nanoclusters

Abstract

Pyridoxal 5′-phosphate (PLP), a biologically important coenzyme, participates in several enzymatic reactions, and its marginal deficiency in the human body can cause cardiovascular disease. However, the excess accumulation of the non-essential Al3+ metal ion in the human body can also cause serious health problems. Therefore, there is significant interest in the detection and monitoring of both PLP and Al3+. This paper introduced a red-emitting dual-ligand co-functionalized copper nanoclusters β-CD-GSH-CuNCs for the simultaneous detection of PLP and Al3+. The capped β-cyclodextrin (β-CD) in β-CD-GSH-CuNCs selectively recognizes PLP by forming a host–guest inclusion complex that caused fluorescence quenching at 625 nm with the formation of an emission band at 488 nm. The ratiometric fluorescence from β-CD-GSH-CuNCs allowed to detect PLP down to 5.29 μM. Further, the in situ-generated nano-assembly β-CD-GSH-CuNCs@PLP showed a selective turn-on fluorescent response for Al3+. The complexation-induced aggregation of nano-assembly resulted in strong fluorescence enhancement at 451 nm that allowed to detect Al3+ down to 0.187 μM. The analytical utility of β-CD-GSH-CuNCs@PLP was validated as a nanoprobe by monitoring Al3+ concentrations in real environmental water samples.

Regulation of the Enzymatic Activities of Lysozyme by the Surface Ligands of Ultrasmall Gold Nanoclusters: The Role of Hydrophobic Interactions

“…The ADAs, which could be encapsulated in polymeric micelle and released under acidic condition, showed better physiological clearance while maintaining serum pharmacokinetics. Moreover, Sahoo et al synthesized a series of fluorescent gold nanoclusters and copper nanoclusters and applied them for the detection of alkaline phosphatase (ALP), salicylaldehyde, VB 6 cofactor pyridoxal 5′-phosphate (PLP), and nitroaromatics. ,,, The gold/copper nanoclusters exhibited a new fluorescence band and showed selective fluorescence enhancement when interacting with these analytes, exhibiting good applicability as nanoprobes.…”

Bioinspired, Non-Enzymatic, Aqueous Synthesis of Size-Tunable CdS Quantum Dots for Sustainable Optoelectronic Applications

“…The successful production of CdS QDs from the full non-enzymatic biochemical cycle is further clarified when the influence of excess reagents on optical measurements is accounted for, including PLP–cysteine–particle complexation, which has been shown to quench and blue-shift the fluorescence of conjugated particles. − Upon precipitation–dissolution-based cleaning of the particulate product, strong absorbance (Figure b), and thus likely significant particle concentration, is only detected in the case of the full non-enzymatic H 2 S chemistry (Scheme ). Photoluminescence of the cleaned products (Figure d) does reveal the formation of fluorescing particles in a subset of the solutions, even in the absence of one or more of the four components of the H 2 S-producing biochemical cycle ( e.g ., Cd + c + P, Cd + c + Fe, and Cd + P + Fe).…”

Metal Nanoclusters in Point-of-Care Sensing and Biosensing Applications

“…The produced β-CD-GSH-CuNCs@PLP nanostructures were then aggregated via Al 3+ ions resulting in the aggregation-induced PL (Figure ). The designed framework provides LODs of 5.29 and 0.187 μM for PLP and Al 3+ ions, respectively …”