Fluorescence turn-on Cu2-xSe@HA-rhodamine 6G FRET nanoprobe for hyaluronidase detection and imaging.

The application of nanostructures to design fluorescence resonance energy transfer (FRET) based sensing platforms has been greatly concerned with the demand for sensitive and selective detection of biomolecules. Here, a novel sensitive turn-on fluorescence strategy based on the FRET mechanism has been designed for hyaluronidase (HAase) detection through the modulation of Cu2-xSe@HA-Rh6G nanoprobe fabricated by self-assembly of rhodamine 6G (Rh6G) together with Cu2-xSe@HA nanoparticles through electrostatic adsorption. The Cu2-xSe@HA had extensive localized surface plasma resonance (LSPR) absorption in the wide range of ultraviolet (UV) to near-infrared (NIR) wavelengths and showed good light capture characteristics, which can be acted as good acceptors in the FRET interactions with Rh6G, inducing its efficient fluorescence quenching. In the presence of HAase, the FRET process was disrupted and the fluorescence signal was recovered. In the range of 0.1-10.0 U/mL, the fluorescence recovery of Rh6G showed a good linear relationship with the concentration of HAase, and the detection limit was 0.06 U/mL. The sensing platform has been used for HAase detection in real urine samples and cancer cells imaging.