Effect of polymer matrix on the sensitivity of microfibrous fluorescent chemosensor containing dendritic porphyrin for the detection of dopamine

Abstract

To use as a fluorescent chemosensor for detecting dopamine, dendritic porphyrin (Den-Por(Zn))-incorporated electrospun microfibrous membranes, polycaprolactone (PCL)-Por(Zn), poly(vinyl acetate) (PVAc)-Por(Zn), and poly(4-vinylpyridine) (P4VP)-Por(Zn), were fabricated. The resulting fibers exhibited a fully interconnected pore structure with narrow pore size distribution. Energy dispersive X-ray spectroscopy and attenuated total reflectance–Fourier transform infrared (ATR–FTIR) results clearly revealed the introduction of dendritic porphyrin on the surface of electrospun membranes. Among the electrospun membranes, P4VP-Por(Zn) exhibited highest sensitivity to dopamine. P4VP-Por(Zn) showed more hydrophilic property than other fibers, and the strong intermolecular interaction between P4VP and dopamine was observed. Therefore, the significant decline of fluorescence intensity even after the reaction with low concentrations of dopamine was measured, in which dopamine probably acted as a quencher. This is attributed to the complex formation between dopamine and Zn of Den-Por(Zn) introduced into the P4VP-Por(Zn) via the chelation.