Color-convertible fluorescent nanoprobe for Parkinson’s disease diagnosis

For the fluorescent diagnosis of Parkinson's disease (PD), molecular probes typically target a single biomarker, which is insufficient because of the limited sensitivity and specificity. Herein, by utilization of the biochemical characteristics with high level of iron and reactive oxygen species (ROS) in PD, an efficient color-convertible fluorescent nanoprobe (TAT-Polyp-QL) was designed and constructed. TAT-Polyp-QL nanoprobe contained a functional iron ligand (L1), a color-convertible fluorescent probe (Q1), and HIV-1 trans-activating transcriptor (TAT) modified hyperbranched polyphosphate (TAT-Polyp), in which TAT was employed as a tool to increase the transport efficiency of the nanoprobe across the blood–brain barrier. Upon meeting high level of iron and ROS in PD, the fluorescent probe Q1 in the TAT-Polyp-QL was oxidized into its sulfoxide derivative, resulting in the blue-shift of fluorescent emission peak from 600 nm to 550 nm and then the fluorescent color conversion from red to green. This unique reaction-based color-convertible fluorescent nanoprobe can be employed for dual-biomarker detection, identifying the emergence of PD in vitro and in vivo with high sensitivity and specificity.