A biomimetic approach to conjugate vitamin B6 cofactor with the lysozyme cocooned fluorescent AuNCs and its application in turn-on sensing of zinc(II) in environmental and biological samples

Abstract

This communication focusses on the synthesis of red fluorescent lysozyme cocooned gold nanoclusters (Lyso-AuNCs) that have been successfully applied for the selective and specific recognition of the vitamin B cofactor pyridoxal-5'-phosphate (PLP). The red fluorescence of Lyso-AuNCs showed remarkable color change to yellow upon conjugation with PLP due to the formation of a Schiff base between the free -NH present in the lysozyme and the -CHO group of PLP. The developed PLP conjugated Lyso-AuNCs (PLP_Lyso-AuNCs) was applied for the selective turn-on recognition of Zn ions in aqueous medium. The yellow fluorescence of PLP_Lyso-AuNCs exhibited significant enhancement at 475 nm in the presence of Zn producing bluish-green fluorescence attributed to the complexation-induced aggregation of nanoclusters. The nanoprobe exhibits nanomolar limit of detection for Zn ions (39.2 nM) and the practicality of the nanoprobe was validated in various environmental water samples and biological plasma, urine, and beetroot extract, with fairly good recovery percent. Also, the system was successfully implemented for the intracellular detection and monitoring of Zn in live HeLa cells. Graphical abstract Applications of red emitting lysozyme cocooned gold nanoclusters (Lyso-AuNCs) for the selective recognition of the vitamin B cofactor pyridoxal-5'-phosphate (PLP) and the conjugated nano-assembly PLP_Lyso-AuNCs for turn-on detection of Zn ions in various environmental and biological samples.

Developing a Cost-Effective Bioassay to Detect Alkaline Phosphatase Activity and Generating White Light Emission from a Single Nano-Assembly by Conjugating Vitamin B6 Cofactors with Lysozyme-Stabilized Fluorescent Gold Nanoclusters

“…Designing of Probe PLP_Lyso-AuNCs. A reported method was adopted to synthesize and characterize the red fluorescent Lyso-AuNCs, 38 which gave two characteristic emission bands at 450 and 665 nm (λ exc = 370 nm) (Figure 1a), and no characteristic surface plasmon resonance band was observed at ∼525 nm of larger gold nanoparticles in the UV− vis spectra. Then, the fluorescence spectra of Lyso-AuNCs were recorded after adding vitamin B 6 cofactors, such as PLP, Py, PyOA, and PyO (Figure 1a).…”

Preparation and characterization of an imogolite/chitosan hybrid with pyridoxal-5′-phosphate as an interfacial modifier

“…9,14,20,24 Especially, the hybrid lm may be particularly effective for metal adsorption. This is because PLP-Schiff base can form complexes with various metals, 30,34 and complexes of zinc and cadmium ions 41,42 have been reported to have strong uorescence. Furthermore, adsorbents should be mechanically strong to withstand owing wastewater.…”

A Review on Biosensors and Nanosensors Application in Agroecosystems

“…Zinc is another important element, and it occurs in a divalent cationic form as Zn 2+ ions. Zn 2+ ion has the capability of sustaining important activities counting synthesis of DNA and protein, RNA transcription, cell apoptosis, and metalloenzyme regulation [ 153 , 154 ]. Usually, fluorescent probes are exploited for detecting the Zn 2+ ions in biological systems.…”

“…The yellow fluorescence of PLP Lyso-AuNCs displays noteworthy augmentation at 475 nm in the occurrence of Zn 2+ generating bluish-green fluorescence which is accredited to the complexation-induced accretion of nanoclusters. The developed nanoprobe can detect Zn 2+ ions in nanomolar concentrations (39.2 nM) [ 154 ]. The dual-emission carbon dots (DCDs) synthesized by Wang et al [ 155 ] can also be exploited for revealing Zn 2+ ions as well as iron ions (Fe 3+ ) in different pH environments.…”