Early diagnostic imaging of pneumonia with an ultra-sensitive two-photon near-infrared fluorescent probe

Abstract

The mortality rate of pneumonia increases significantly with the prolongation of illness. In the pursuit of a tool to accurately diagnose pneumonia in its early stages, we designed and synthesized a two-photon near-infrared fluorescent probe (DCQN) to identify increased concentrations of the inflammation marker SO₂. The probe was found to specifically react with SO₂ by undergoing a 1,4-addition reaction to generate near-infrared fluorescence with good sensitivity (6 s), a large Stokes shift (110 nm) and low detection limit (1.49 nM). DCQN has near-infrared emission as well as good two-photon performance, which can image exogenous and endogenous SO₂ in cells and avoid interference from background fluorescence from cells. Furthermore, this study achieved accurate imaging of a pneumonia lesion site in deep tissues to provide a tool for the fluorescence diagnostic imaging of pneumonia <i>in situ</i>.