A nuclear-staining water-soluble polycationic two-photon DNA probe for identifying dead neuronal cells and monitoring traumatic brain injury

Abstract

Neuronal cells are in most part exempt from the daily flux of cell birth and death. The identification of dead neuronal cells is essential for facilitating our understanding the types, mechanisms, and roles of neuronal cell death in physiology and pathology, and also the investigation and treatment of neurodegenerative diseases. It is highly desirable to fabricate fluorescent probes with strong binding affinity, high brightness, and long-wavelength excitation able to identify dead neuronal cells. In this study, we developed a water-soluble polycationic two-photon fluorescent probe (BTD-V) for identifying dead neuronal cells. The hydrophilic nature and positive charged polycation enabled BTD-V to selectively accumulate in nuclei dead cells. BTD-V also exhibits a large Stokes shift of 176 nm, enhanced high brightness of 13251 M-1 cm-1 upon binding with DNA, strong DNA-binding ability with an apparent disassociation constant of 0.75 nM. Based on these properties, the probe can be used to effectively monitor different types of neuronal cell death induced by hydrogen peroxide and glutamate due to differences in the nuclear morphologies. The BTD-V probe can also be used for two-photon brain imaging, enabling the monitoring of traumatic brain injury (TBI) mice by staining the dead nuclei of paraffin sections and cryosections. This research provides a promising DNA probe for identifying dead cells, discriminating cell death type, and monitoring neuronal-related diseases.

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