Silica-supported dual-dye nanoprobes for ratiometric oxygen sensing
Oxygen (O2) levels provide an important parameter in the early-stage diagnosis of cancers and other diseases. Ratiometric optical O2 sensing has attracted much interest due to its better calibration of oxygen levels at two wavelengths. Oxygen sensing nanoprobes are generally designed by incorporation of reference dye and phosphorescent indicator into various matrixes. Silica nanomaterials with intrigue characteristic properties are highly preferable in hypoxia sensing. However, physical entrapments of dyes in silica suffered from leaching and moderate sensitivity. Reported herein is a covalently encapsulated dual-dye silica nanoprobe for ratiometric oxygen detection and imaging. The nanoprobe prepared in one-pot approach have a core-shell nanostructure that silanized indicators and reference dyes are covalently grafted within silica core, while poly(ethylene glycol) chains form an outer shell. To our delight, high phosphorescence brightness, long lifetime and excellent stability of the nanoprobe were achieved through the covalent-bonding of the dyes for efficient energy transfer between reference dye and indicator. More importantly, the designed nanoprobe can respond to different oxygen levels in both solution and living cells with impressive sensitivity and stability.
- This article is part of the themed collection: The 1st Sauvage Symposium