Ultrafine fluorene-pyridine oligoelectrolyte nanoparticles for supersensitive fluorescence sensing of heparin and protamine

A new fluorene-pyridine oligoelectrolyte (OFP) is rationally proposed and readily synthesized via a simple one-pot Sonogashira approach. Hence, an unexpectedly small cationic oligomer nanosensor (i.e. OFPNPs, similar to 1.2 nm in diameter) was conveniently fabricated owing to the enhanced flexibility endowed by the meta-substituted pyridyl unit. Inspiringly, this facile nanoplatform with low cytotoxicity favors the ultrasensitive fluorescence assay for heparin and protamine with a detection limit (LOD, S/N = 3) as low as 1.2 ng mL(-1) and 0.5 ng mL(-1), respectively, involving heparin-induced aggregation of OFPNPs through electrostatic interaction or competitive rebinding of protamine to heparin.

Automated summary

A new fluorene-pyridine oligoelectrolyte (OFP) was synthesized using a simple one-pot Sonogashira approach, leading to the fabrication of a small cationic oligomer nanosensor OFPNPs with a diameter of approximately 1.2 nm. This nanoplatform, with low cytotoxicity, enables ultrasensitive fluorescence detection of heparin and protamine at detection limits as low as 1.2 ng mL(-1) and 0.5 ng mL(-1) respectively.