Silicon Nanowires-Based Fluorescence Sensor for Cu(II)

Si nanowires (SiNWs) were covalently modified by fluorescence ligand, N-(quinoline-8-yl)-2-(3-triethoxysilyl-propylamino)-acetamide (QlOEt) and finally formed an optical sensor to realize a highly sensitive and selective detection for Cu(II). The QlOEt-modified SiNWs sensor has sensitivity for Cu(II) down to 10(-8) M, which is more sensitive than QlOEt alone. Metal ions interferences have no observable effect on the sensitivity and selectivity of QlOEt-modified SiNWs sensor. The SiNWs-based fluorescence sensor is reversible by addition of acid to replace Cu(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 even to nanosensors for direct detection of specific materials in intracellular environment.