Tuning of förster resonance energy transfer in metal–organic frameworks: Toward amplified fluorescence sensing

Abstract

The assembly of Förster resonance energy transfer (FRET) donor and acceptor for amplified fluorescence sensing has been considered a big challenge. Herein, by using the multivariate approach, we report the design and synthesis of a series of FRET-based metal–organic frameworks (MOFs) with variable donor fluorophore-to-the-acceptor ratios. Owing to the efficient FRET process, these MOFs are almost non-fluorescent. Interestingly, the reduction of the acceptor leads to the prohibition of the FRET process and turns on the fluorescence of MOFs. More significantly, interesting amplification phenomena were observed when these MOFs were utilized as fluorescent turn-on sensors for a reductive analyte. For example, upon varying the ratio of donor fluorophores and acceptors from 0.7 to 11.4, the limit of detections exhibited 157 times decrease. We believe the present study not only provides a simple but general strategy for the efficient construction of amplified fluorescent sensors, but also will inspire us to design ultrasensitive MOF-based sensors in the future.