Dual-color fluorescent nanoparticles showing perfect color-specific photoswitching for bioimaging and super-resolution microscopy

Abstract

Dual-emissive systems showing color-specific photoswitching are promising in bioimaging and super-resolution microscopy. However, their switching efficiency has been limited because a delicate manipulation of all the energy transfer crosstalks in the systems is unfeasible. Here, we report a perfect color-specific photoswitching, which is rationally designed by combining the complete off-to-on fluorescence switching capability of a fluorescent photochromic diarylethene and the frustrated energy transfer to the other fluorescent dye based on the excited-state intramolecular proton transfer (ESIPT) process. Upon alternation of UV and visible light irradiations, the system achieves 100% switching on/off of blue emission from the diarylethene while orange emission from the ESIPT dye is unchanged in the polymer film. By fabricating this system into biocompatible polymer nanoparticles, we demonstrate microscopic imaging of RAW264.7 macrophage cells with reversible blue-color specific fluorescence switching that enables super-resolution imaging with a resolution of 70 nm.

Turn-on mode diarylethenes for bioconjugation and fluorescence microscopy of cellular structures

“…Therefore, merging photochromic and fluorescent properties in a single entity attracted a lot of attention over past decades ( 2 , 6 – 9 ). Photoresponsive fluorescent DAEs (fDAEs) are particularly advantageous in life ( 10 – 16 ) and material science ( 17 – 23 ) applications. For example, fDAEs are very promising on−off switching fluorophores for superresolution fluorescence microscopy or nanoscopy, as these methods rely on transitions between dark (off) and fluorescent (on) states for distinguishing neighboring fluorescent molecules at subdiffraction length scales (<200 nm) ( 24 – 27 ).…”

Fulgide Derivative-Based Solid-State Reversible Fluorescent Switches for Advanced Optical Memory

“…[21][22][23][24] Solid-state fluorescent switches are preferable in practical applications, such as anticounterfeiting, 25,26 data storage, 27,28 optical devices, 29 and biological imaging. 30,31 For example, diarylethene derivatives exhibiting fluorescent switching properties in the solid state with a high and constant fluorescence on-off switching ratio have been developed and applied in accurate nonvolatile optical memories [32][33][34] and super-resolution imaging. [35][36][37] A tetraphenylethylene-SP (TPE-SP) molecule has been designed and synthesized, and a solid-state fluorescent switch as a near-infrared (NIR) microlaser has been constructed by selfassembling TPE-SP microspherical caps.…”

Dual Color Imaging from a Single BF2-Azadipyrromethene Fluorophore Demonstrated in vivo for Lymph Node Identification

“…In this work the goal was to achieve dual color imaging in both the ICG and MB wavelength ranges from a single NIR-AZA fluorophore, which if achievable would open new possibilities for simultaneous imaging in two colors. Previously reported strategies for multiplexing in two colors take the form of using a physical scaffold such as a nanoparticle and embedding or covalently attaching two different fluorophores with distinct emission wavelengths 16 , 17 , 18 . It was envisioned that a more bio-medically compatible format could be achieved utilising a specifically substituted single NIR-AZA fluorophore from which an emission in two distinct spectral regions could be obtained.…”