New polyacetylene-based chemosensory materials for the “turn-on” sensing of α-amino acids

For the first time, a new disubstituted polyacetylene (P1) was utilized to sense α-amino acids based on a “turn-on” model, through an indirect approach. Thus, first, the strong blue fluorescence of P1 was quenched by trace copper ions efficiently, then the addition of α-amino acids to the P1/Cu2+ complex could recover the strong fluorescence of P1 to report the presence of α-amino acids. Interestingly, the P1/Cu2+ complex demonstrated much higher sensitivity towards histidine, with the detection limit of ∼2 ppm (∼1.3 × 10−5 mol/L). With the aid of a normal UV lamp, histidine could be differed from other α-amino acids visually by the observation of its strong blue fluorescence, at the concentration as low as 4.0 × 10−5 mol/L. Due to the convenient synthesis of P1, and the so far reported many other conjugated fluorescent polymers, the work reported here might open up a new avenue to develop new biosensors.