A Simple and Efficient Turn‐Off Fluorescence Sensor for the Nanomolar Detection of Homovanillic Acid Using Protein Mediated Blue Emitting Nickel Nanoclusters

Abstract

Homovanillic acid (HVA) is a catecholamine metabolite that plays a vital role in the diagnosis of several neurological disorders. Thus, a simple and cost‐effective sensing strategy for HVA determination is significant. Herein, we describe the development of a turn‐off fluorescence sensor for the effective determination of HVA using bovine serum albumin stabilized nickel nanoclusters (BSA NiNCs). This biocompatible and water‐suspended fluorophore exhibited strong emission at 405 nm upon exciting at 325 nm. The fluorescence intensity of BSA NiNCs was efficiently quenched by the addition of HVA within the linear range 9.00×10−7 M–5.00×10−8 M with a limit of detection of 9.23×10−9 M. A static quenching mechanism was proposed for the sensor due to the aggregation of BSA NiNCs on adding HVA. The practical utility of the sensor was tested in artificial urine and blood serum and a good recovery using the spike‐recovery method were obtained.

Ratiometric Fluorescence Capillary Sensor-Integrated Molecular Imprinting for Simultaneous Detection of Two Biological Indicators of Parkinson’s Disease

“…The Si-CD@CdTe@CMIP had a broader determination range compared with other methods. The LOD of Si-CD@CdTe@CMIP was lower than that of trace analysis in previous studies. − ,− Importantly, the Si-CD@CdTe@CMIP method achieved the lower detection limit with a lower sample consumption of 18 μL, which proved that the Si-CD@CdTe@CMIP can be used for detection of trace samples.…”

“…There was no overlap between the fluorescence emission of Si-CD and the absorbance spectra of HVA, indicating that PET happened in a nonradioactive decay pathway, which caused the fluorescence quenching . The negative group of Si-CD could interact with the carboxyl group of HVA, and the electron of Si-CD was transferred to HVA, which may cause the fluorescence quenching . Meanwhile, Al 3+ did not produce UV–vis absorbance resulting in a nonoverlap between the fluorescence emission of Si-CD and CdTe QDs and the absorbance peak of Al 3+ , which illustrated that PET occurred in Al 3+ and the two fluorescence sources.…”

“…Simultaneously, excessive levels of Al 3+ in the body can lead to serious diseases such as dementia, PD, and Alzheimer’s disease. Studies showed that the level of HVA decreases while the concentration of Al 3+ increases in PD patients. − Thus, simultaneous detection of HVA and Al 3+ is of great significance for the early diagnosis and monitoring of PD. Currently, the detection methods of HVA or Al 3+ included enzymatic immunological assays (EIA), liquid chromatography (LC), gas chromatography–mass spectrometry (GC–MS), and high-performance liquid chromatography (HPLC). − However, these methods have some shortcomings such as the lack of specificity, poor sensitivity, large reagent consumption, and individual determination …”