Applications of vitamin B6 cofactor pyridoxal 5′-phosphate and pyridoxal 5′-phosphate crowned gold nanoparticles for optical sensing of metal ions

Abstract

Vitamin B6 cofactor pyridoxal 5′-phosphate (PLP) and PLP crowned gold nanoparticles (PLP-AuNPs) was applied for the optical chemosensing of metal ions in aqueous medium. PLP showed a visually detectable colour change from colourless to yellow and ‘turn-off’ fluorescence in the presence of Fe3+. The fluorescence intensity of PLP at 433nm was also blue-shifted and enhanced at 395nm upon addition of Al3+. When the PLP was functionalized over AuNPs surface, the wine red colour of PLP-AuNPs was turned to purplish-blue and the SPR band at ~525nm was red-shifted upon addition of Al3+, Cd2+ and Pb2+ due to the complexation-induced aggregation of nanoparticles. The developed sensing systems exhibited good selectivity and specificity for the detected analytes (Fe3+, Al3+, Cd2+ and Pb2+).