“OFF-ON” sensor for detecting heparin based on Hg2+-quenching of photoluminescence nitrogen-rich polymer carbon nanoribbons

- The nitrogen-rich polymer carbon nanoribbons probe serves as a selective photoluminescence sensor for heparin over competitor biomolecules.
- A stronger electrostatic attraction between metal ion (Hg2+ ion) and heparin than Hg2+ ion with oxygen/nitrogen elements is reported here.
- The detection of heparin with high sensitivity and selectivity.
- Good applicability of the sensor contributes to specific effects between Hg2+ ion and heparin.

A new strategy for the detection of heparin is developed by utilizing photoluminescence nitrogen-rich polymer carbon nanoribbons (NRCNRs) and Hg2+ ion. The emission of NRCNRs is found to be quenched in the presence of Hg2+ ion by energy and electron transfer. Upon addition of the polyanionic heparin, the quencher (Hg2+ ion) has been removed from the surface of NRCNRs owing to the stronger anion-cation interactions between heparin and Hg2+ ion, which leads to significant photoluminescence recovery of NRCNRs, allowing analysis of heparin in a very simple method. By employing this sensor, excellent linear relationship exists between the recovery degree of the NRCNRs and the concentration of heparin in the range of 0.05-50 μg mL−1. The detection limit for heparin is 0.013 μg mL−1, which is comparable to other sensors. The simultaneous possession of high sensitivity and selectivity, convenience, rapidity, and visualization could enable this sensor to be potentially applicable for ultrasensitive and rapid on-site detection toward trace heparin.