Self-Assembled FRET Nanoprobe with Metal–Organic Framework As a Scaffold for Ratiometric Detection of Hypochlorous Acid

Abstract

Metal-organic framework (MOF) has been extensively explored in a number of fields due to its diverse properties. In this work, we demonstrated the potential of MOF in the establishment of self-assembled fluorescence resonance energy transfer (FRET) system for developing ratiometric fluorescent nanoprobe. For this purpose, zeolitic imidazolate framework-8 (ZIF-8) was selected as a MOF model to entrap carbon dot (CD) and curcumin (CCM) during its self-assembly, which produces CD/[email protected] Benefiting from the confinement effect of ZIF-8, the loaded CD and CCM can be brought in close proximity to occur energy transfer. Under optimal conditions, a high FRET efficiency of 68.7 % can be obtained. Importantly, compared with traditional FRET systems, the fabrication process of CD/[email protected] is much more simple and straightforward, which does not involve in the elaborate design and complicated synthesis of molecular linkers. However, in the presence of hypochlorous acid (HClO), the FRET process from CD to CCM will be disrupted, rendering CD/[email protected] to display a ratiometric response to HClO. This finding led to a method for ratiometric fluorescent detection of HClO with a detection limit of 67 nM and excellent selectivity over other reactive oxygen species. We believe that this study can give a new insight to the rational design and application of FRET-based nanoprobes.