Photofluorochromic water-dispersible nanoparticles for single-photon-absorption upconversion cell imaging

Abstract

Photofluorochromic diarylethene (DAE) molecules have been widely investigated due to their excellent fatigue resistance and thermal stability. However, the poor water solubility of DAEs limits their biological applications to some extent. Herein, we reported two kinds of water-dispersible DAE nanoparticles (DAEI-NPs and DAEB-NPs), in which DAE molecules were stabilized by the amphiphilic polymer DSPE-mPEG2000 using the nanoprecipitation approach. The fabricated nanoparticles retain well-controlled luminescence and fluorescence photoswitching properties in aqueous solution, which could be reversibly switched on and off under the alternating irradiation of ultraviolet (UV) and visible light. In addition, the closed-ring isomers of DAEB-NPs performed hot-band-absorption-based photon upconversion when excited by a 593.5 nm laser. Bearing excellent photophysical properties and low cytotoxicity, DAEB-NPs were applicable for upconversion cell imaging without high-excitation power density and free from oxygen removal. Additionally, the imaging process could be switched on by regulating the photofluorochromic nanoparticles.

Designing of a pH-activatable carbon dots as a luminescent nanoprobe for recognizing folate receptor-positive cancer cells

“…Investigation of high-resolution optical imaging using fluorescent nanomaterials for cellular labeling can be considered as a turning point in biomedical field [9]. These nanomaterials have particular properties, including unique optical, catalytic, and magnetic features which are appropriate for cellular labeling and optical imaging [10][11][12]. Prominent fluorescent nanomaterials in imaging and cellular labeling fields are quantum dots (QDs) [13] which can be classified into carbon and graphene QDs [14].…”

Photochromic diarylethene induced fluorescence switching materials constructed by non-covalent interactions

“…In the last few decades, photoswitchingbased techniques have revolutionized fluorescence imaging, promising super-resolution or ultra-high sensitivity. [97][98][99][100][101][102] On the one hand, the fluorescence switching process can distinguish the real signal of biological samples from the background signal and autofluorescence, which will greatly improve the signal-to-noise ratio and obtain higher imaging resolution. On the other hand, the fluorescence switching process can also be applied to selectively illuminate specific areas, which helps to overcome the diffraction limit and achieve super-resolution fluorescence imaging.…”