Improvement of the fluorescent sensing biomarker 3-nitrotyrosine for a new luminescent coordination polymer by size regulation

Abstract

Luminescence sensing of biomarker 3-nitrotyrosine (3-NT) with coordination polymers (CPs) is of great significance and rarely investigated, especially in improving the sensing performance by regulating the particle of CPs. Herein, we synthesized a new 3D LCP, [Cd₃(L)(BTC)₂(H₂O)₂]·2H₂O (LCP 1) (H₃BTC = 1,3,5-benzenetricarboxylic acid, L = (E)-4,4′-(ethene-1,2-diyl)bis[(N-pyridin-3-yl)benzamide]), which demonstrates a rare example of direct detecting 3-NT by LCPs as fluorescent sensors. Meanwhile, nanoscale LCP 1 (Nano-LCP 1) with a smaller size was prepared by adjusting the reaction conditions. Nano-LCP 1 not only shows the same high selectivity, anti-interference ability and fast response time as LCP 1, but also has a higher quantum yield (31.80%, about 3 times that of Bulk-LCP 1) and a lower detection limit (2.30 × 10⁻⁸ M, about 20 times that of Bulk-LCP 1). A detailed detection mechanism of LCP 1 towards 3-NT and the effect of the size difference on the luminescence sensing performance were discussed, providing a valuable reference for the rational design, mechanism interpretation, and performance improvement of LCP-based fluorescence sensors.