Label-free, resettable, and multi-readout logic gates based on chemically induced fluorescence switching of gold nanoclusters

Herein, we present a label-free, resettable, multi-readout, and fluorescent logic system by employing bovine serum albumin (BSA) and 3-mercaptopropionic (MPA) co-stabilized gold nanoclusters (BSA/MPA–AuNCs) as a basic work unit. Small chemical molecules including Fe2+, Fe3+, H2O2 and H+/OH− are selected as the inputs to induce the change in fluorescence intensity of BSA/MPA–AuNCs through a non-radiative electron transfer mechanism. Using this novel strategy, a versatile logic system capable of performing elementary logic operations (NAND, NOR, and IMPLICATION) and integrative logic operations (NAND + NOR) can be successfully constructed. More importantly, the logic operations can be also performed on a solid surface in which BSA/MPA–AuNCs are complexed with polyelectrolytes and are coated on a glass slide. We envision that the current work will bring new ideas in establishing chemical logic gates in both liquid media and solid forms.