Vitamin B₆ Cofactor‐Conjugated Polyethyleneimine‐Passivated Silver Nanoclusters for Fluorescent Sensing of  Zn²⁺ and  Cd²⁺ Using Chemically Modified Cellulose Strips

Abstract

This work presents the fluorescent turn‐on sensing of Zn2+ and Cd2+ by using a nano‐assembly designed by the surface modification of the blue fluorescent polyethyleneimine (PEI) passivated silver nanoclusters (PEI‐AgNCs) with the vitamin B6 cofactor pyridoxal 5‘‐phosphate (PLP) in aqueous medium. The cofactor PLP was conjugated through the Schiff base condensation between the ‐CHO group of PLP and the free –NH2 present in PEI‐AgNCs. The formation of nano‐assembly PLP_PEI‐AgNCs was ascertained from various characterization along with the fluorescent color change from blue to yellow. Upon addition of Zn2+ and Cd2+, the yellow fluorescent of PLP_PEI‐AgNCs instantaneously and selectively changed to bluish‐green with a significant fluorescence enhancement at 475 nm. The developed nanoprobe shows the detection limit down to 50.5 x 10−8 M for Zn2+ and 59.0 x 10−8 M for Cd2+ without any interference from other tested metal ions and was applied for the recognition of Zn2+ and Cd2+ in various environmental and biological fluids with good recovery %. Also, the PLP conjugated PEI‐AgNCs was covalently anchored over the cellulose paper strips, characterized and then applied for the detection of Zn2+ and Cd2+. In addition, the developed system has been employed for the qualitative detection of intracellular Zn2+ in live HeLa cells by fluorescence imaging.

Highly selective and sensitive electrochemical sensing of trace Zn2+ ions, by grafted Tricholoma mushroom polysaccharide/Ag composite nanoparticles in aqueous medium

“…Figure 6 shows the XPS spectra of TMPSGP‐Ag NPs where two clear and distinct peaks are arised with binding energy 368.92 and 375.17 eV, indicating 3d 5/2 and 3d 3/2 state of metallic Ag(0), respectively. [ 34 ] The above results signify that Ag(I) state in AgNO 3 convert to metallic Ag(0) during the Ag NPs formation by gaining the electron from TMPSGP.…”

Simple, Rapid, and Highly Sensitive Colorimetric Sensor Strips from a Porous Cellulose Membrane Stained with Victoria Blue B for Efficient Detection of Trace Cd(II) in Water

“…Cadmium pollution was a serious threat to human health and environmental safety as the levels of cadmium (Cd 2+ ) increase in soil and water supplies. − Recently, cellulose-based colorimetric sensors were widely used in the detection of cadmium ions due to several attractive advantages, such as low cost, simplicity, being easy to read, speed, and accuracy. , The detection result of cellulose-based colorimetric sensors can be achieved merely by the naked eye without help from any complicated instrument . However, cellulose membrane-based colorimetric sensors are rarely reported.…”

Decorating Vitamin B6 Cofactor over Beta-Cyclodextrin Stabilized Silver Nanoparticles through Inclusion Complexation for Fluorescent Turn-On Detection of Hydrazine

“…The yellow colored silver nanoparticles showed a characteristic absorption band at ∼400 nm due to the surface plasmon resonance (SPR) . When the size of the silver nanoparticles is decreased to ultrasmall size, i.e., size less than about 3 nm, striking multicolored emission from visible to NIR region can also be observed . Therefore, the functionalized silver nanoparticles are applied for the designing of both colorimetric and fluorescent sensors.…”