Dual-responsive luminescent dye@MOF hybrids for ratiometric trace detection, colorimetric visualization, and precise discrimination of tetracycline antibiotics

Abstract

In this work, dual-responsive luminescent Her@Zn-Bim hybrids are developed by herniarin (Her) dye encapsulation engineering within a layered host MOF (Zn-Bim). The pore confinement effect of the Zn-Bim host effectively isolates the guest dye molecules, therefore affording bright blue dye emission for Her@Zn-Bim hybrids. Upon exposure to tetracycline antibiotics (TCs), the hybrid undergoes a significant quenching of the blue emission, concurrent with the appearance of a distinct green emission. This dual-emission response is very fast and sensitive, facilitating real-time ratiometric detection of TCs with a low limit of detection of 7.81 nM. Notably, the ratiometric luminescence response manifests as a readily observable blue-to-green color switching, enabling straightforward and colorimetric visualization of TCs. Visual and semiquantitative monitoring of TCs is achieved using a readily available smartphone installed with a color-analysis app. Furthermore, in conjunction with principal component analysis, the Her@Zn-Bim hybrids demonstrate efficient discrimination of four TCs with high structural and chemical similarities, even in complex mixture systems. The mechanisms underlying the luminescent responses of the hybrids towards TCs are carefully elucidated. These hybrid sensors, featuring high sensitivity, fast response, colorimetric visualization, and precise discrimination capability, hold promising potential for practical applications in sensing TCs.