A Small-Molecule Ratiometric Photoacoustic Probe for the High-Spatiotemporal-Resolution Imaging of Copper(II) Dynamics in the Mouse Brain

Copper dysmetabolism is associated with various neurodegenerative disorders, making high-spatiotemporal-resolution imaging of Cu2+ in the brain essential for understanding the underlying pathophysiological processes. Nevertheless, the current probes encounter obstacles in crossing the blood-brain barrier (BBB) and providing high-spatial-resolution in deep tissues. Herein, we present a photoacoustic probe capable of imaging Cu2+ dynamics in the mouse brain with high-spatiotemporal-resolution. The probe demonstrates selective ratiometric and reversible responses to Cu2+ , while also efficiently crossing the BBB. Using the probe as the imaging agent, we successfully visualized Cu2+ in the brain of Parkinson's disease (PD) model mouse with a remarkable micron-level resolution. The imaging results revealed a significant increase in Cu2+ levels in the cerebral cortex as PD progresses, highlighting the close association between Cu2+ alternations in the region and the disease. We also demonstrated that the probe can be used to monitor changes in Cu2+ distribution in the PD model mouse brain during L-dopa intervention. Mechanism studies suggest that the copper dyshomeostasis in the PD mouse brain was dominated by the expression levels of divalent metal transporter 1. The application of our probe in imaging Cu2+ dynamics in the mouse brain offers valuable insights into the copper-related molecular mechanisms underlying neurodegenerative diseases.

Synthesis, crystal structure, photoluminescence and catalytic properties of a novel cuprous complex with 2,3-pyrazinedicarboxylic acid ligands

A copper (I) polymer, [Cu2Mg(pzdc)2(H2O)5•2H2O]n (pzdc = 2,3-Pyrazinedicarboxylic acid), was synthesized by solvothermal method. The complex was characterized using X-ray diffraction (XRD), fourier transform infrared spectroscopy (FT-IR), ultraviolet-visible spectrophotometry (UV-Vis), and element analysis. X-ray crystal structure analysis reveals that the complex is a two-dimensional coordination polymer. The photophysical and luminescent properties of the complex were investigated. At room temperature, the complex exhibits reversible double strands cyclic voltammogram and displays efficient blue emission with peak maxima at 468 nm. Catalytic liquid phase oxidation of dyes and glyphosate was carried out using the copper (I) polymer as catalyst and H2O2 as oxidant. Degradation efficiencies were evaluated by varying the reaction conditions (i.e. illumination and oxidant). In the degradation reactions, the polymer exhibits high degradation efficiency within a short reaction time under the optimum reaction conditions. Furthermore, the reusability of the catalyst is excellent, showing no activity loss in four repeated cycles. The possible reaction mechanism catalyzed by the polymer was inferred on the basis of the results of electron spin resonance (ESR), electrochemical and ion chromatography analyses (IC).