Enhanced Chemical Fluorescence-Based Sensing Using Metallic Nano-Composites

摘要

It has been recently shown that the favorable effects of enhanced fluorescent intensities, reduced lifetimes (increased probe photostabilities), enhanced and localized rates of multiphoton excitation, and modified rates of energy transfer can occur for fluorophores or biological species of interest, in close proximity to noble metallic nano-structures and surfaces. Subsequently, nano-metal-enhanced fluorescence (NanoMEF) is yielding enormous opportunities for enhanced fluorescence sensing and imaging in microfluidics, lab-on-a-chip, clinical diagnostics, and cellular applications. NanoMEF is a through-space phenomenon relying on interaction of fluorophores with metallic nano-particles in the presence of excitation light. MEF can be utilized to produce nanometer-size sensors, which display enhanced spectral properties, whie still potentially maintaining a probes free space-sensing functionalities. In this presentation we report our recent findings on the effects of silver nano-particles on the spectral properties of two representative fluorescent probes for pH and Ca~(2+) measurements. We demonstrate that quantum efficiencies of probes are greatly enhanced providing more reliable chemical sensing capabilities. Our findings promise a new class of potential sensors, which we believe could constitute a new breed of composite nanosensors based on metal-enhanced fluorescence and their applications in miniaturized systems.