Dye displacement on a GO-like cationic porphyrin polymer for heparin sensing and quality control

It is meaningful but challenging to develop convenient and accurate analytical methods for heparin sensing, owing to its complex and heterogeneous chemical structure. Although indicator displacement assay offers a promising alternative, the number of suitable host molecules capable of accommodating heparin remains limited.

Two positively charged porphyrin-based polymers, A30 and A32, are synthesized via alkylation reactions between 5,10,15,20-tetra(4-pyridyl)porphyrin and corresponding linkers of 1,2-diiodoethane and p-Xylylene dibromide, respectively. These polymers are designed to interact effectively with heparin through multiple hydrogen bonding and electrostatic interactions. Especially, A30 and A32 exhibit graphene oxide-like fluorescence quenching behavior, enabling their use as a general platform for constructing non-fluorescent polymer-dye ensembles. Therefore, a four-component sensor array named PSA is constructed by simple mixing A30 and A32 with representative dyes for heparin sensing.

The PSA sensor array demonstrates satisfactory performance in discriminating common glycosaminoglycans, including heparin, chondroitin sulfate, and hyaluronic acid. Furthermore, it has been successfully applied for quantifying heparin concentration in diluted serum samples, detecting glycosaminoglycan contaminants in heparin, and accurately identifying unknown glycosaminoglycan samples in an accurate and convenient way.