An ATP responsive fluorescent supramolecular assembly based on a polyelectrolyte and an AIE active tetraphenylethylene derivative.

Aggregation induced emission (AIE) active probes have attracted enormous attention due to their wide-spread and ever increasing number of applications in the sensing of chemically and biologically important molecules. AIE probes undergo drastic modulation in their photophysical features from a monomeric to aggregated state. In the current work, we report the aggregation of tetra-anionic Su-TPE (AIE active probe) in the presence of a cationic polyelectrolyte, poly(allylaminehydrochloride) (PAH). A supramolecular assembly is formed by the electrostatic interaction between cationic PAH and anionic Su-TPE molecules, which leads to drastic modulations in the spectral features of anionic Su-TPE upon addition of cationic PAH. The Su-TPE-PAH aggregate assembly has been investigated using various photophysical techniques, such as, ground-state absorption, steady-state and time-resolved emission spectroscopic techniques along with 1H NMR measurements. The Su-TPE-PAH aggregate assembly is found to be responsive towards the ionic strength of the medium and temperature which results in drastic modulations of the spectral features of the emissive supramolecular aggregate assembly. Finally, the specific recognition of an important bioanalyte, ATP, has been achieved using the formed Su-TPE-PAH supramolecular aggregate assembly as a sensing platform which displays good selectivity and high sensitivity towards ATP. Importantly, the developed sensor platform could also function in the human serum matrix, hence, demonstrating the potential of the established sensor platform for real-life applications in near future.