Silicon Nanowires-Based Fluorescence\nSensor for Cu(II)

Abstract

Si nanowires (SiNWs) were covalently modified by fluorescence ligand, <i>N</i>-(quinoline-8-yl)-2-(3-triethoxysilyl-propylamino)-acetamide (QlOEt)\nand finally formed an optical sensor to realize a highly sensitive and selective detection for Cu(II). The QlOEt-modified SiNWs sensor has\nsensitivity for Cu(II) down to 10^-8 M, which is more sensitive than QlOEt alone. Metal ions interferences have no observable effect on the\nsensitivity and selectivity of QlOEt-modified SiNWs sensor. The SiNWs-based fluorescence sensor is reversible by addition of acid to replace\nCu(II). The sensing mechanisms of QlOEt-modified SiNWs to Cu(II) and the rationale for the increase in sensitivity and selectivity of QlOEt-modified SiNWs over QlOEt on Cu(II) are discussed. The current sensor structure may be extendable to other chemo- and biosensors, and\neven to nanosensors for direct detection of specific materials in intracellular environment.