Förster resonance energy transfer-based biosensing platform with ultrasmall silver nanoclusters as energy acceptors

We studied the energy transfer (ET) property of ultrasmall Ag nanoclusters (Ag NCs) and exploited its biosensing application for the first time. A hybridized DNA duplex model was designed to study the energy transfer process from fluorescent energy donors to Ag NCs. By changing the DNA duplex model and the number of hybridized pairs, the separation distance between the energy donor and Ag NCs was adjusted to investigate the distance dependence and possible mechanisms involved in the ET process, which was assigned to Förster resonance energy transfer (FRET). Using Ag NCs with different photophysical properties as energy acceptors, FRET-based biosensing platforms with two different energy donors were constructed utilizing either the off-on or ratiometric fluorescence signaling. This study will provide the basis for understanding energy transfer properties of Ag NCs and bring to light the universal application of these properties in bio/chemo sensing.