Efficient Imidazolium-Biomolecule Interaction-Assisted Amplified Quenching for Ultrasensitive Detection of Heparin

Detection of heparin (HP) under physiological conditions is difficult due to the presence of biological obstructions including proteins and lipids. Thus, it is highly challenging to selectively detect HP and to increase its sensitivity in complex systems. Here, we report the detection of HP at nanomolar levels via efficient imidazolium-HP interaction-assisted fluorescence quenching amplification. The self-assembled pyrenyl aggregates are devised as a conduit for efficient exciton transport, which induces amplified fluorescence quenching for HP detection. This amplified quenching is enhanced by introducing an imidazolium receptor designed to have a high affinity to HP via electrostatic and/or additional interactions with C2 protons, resulting in a very high Stern-Volmer quenching constant of approximately 1.17×10⁸  M^-1 .