Nanomolar Cu2+Detection in Water Based on Disassembly of AIEgen: Applications in Blood Serum, Cell Imaging and Complex Logic Circuits

Abstract

AbstractHere in, we report self‐assembled aggregates of AIEgen 1, which exhibits excited state intramolecular proton transfer (ESIPT) coupled aggregation induced emission (AIE) with intense green fluorescence (λem=526 nm) in aqueous solution as well as in solid state. AIEgen 1 behaves as disassembly based fluorescent probe for selective and sensitive detection of Cu2+ in drinking water with lowest limit of detection of 0.261 ppb (4.13 nM) (much lower than recommended by EPA). AIEgen 1 finds applications for the detection of Cu2+ in blood serum, environmental (tap, pond and industrial waste water) samples. Probably the interaction of Cu2+ ions at Schiff‐base unit of AIEgen 1 via metal chelation disrupts the self‐assembled aggregates and results in disassembly of the nanorods into smaller spherical nanostructures as also evidenced in DLS, SEM and TEM studies. Incubation of HeLa cells with AIEgen 1 results in fluorescence ‘switch‐on’ showing cell internalization of AIEgen 1 with low cytotoxicity and thus establishes the potential of AIEgen 1 in cell imaging. The reversibility influorescence / absorbance of 1‐Cu2+ complex with EDTA helps in elaboration of various reconfigurable and superposed logic gates such as NOT (at F425, A380), INH (at A430), IMP1 (at A380) and IMP2 (at F526). By observing the output switching in absorbance and fluorescence channels on addition of Cu2+ (In1) and EDTA (In2) as inputs, ‘set‐ reset’ flip flop memory element and complementary IMP/INH logic circuits have been elaborated.