Encapsulation of Dual‐Emitting Fluorescent Magnetic Nanoprobe in Metal‐Organic Frameworks for Ultrasensitive Ratiometric Detection of Cu²⁺

Abstract

An effective dual-emission fluorescent metal-organic framework (MOF)-based nanoprobe has been established for ultrasensitive and rapid ratiometric detection of Cu . Such a nanoprobe was prepared by encapsulating fluorescein isothiocyanate (FITC), and Eu(III) complex-functionalized Fe O into the zeolitic imidazolate framework material (ZIF-8). In this nanoprobe, FITC was used as a reference signal, thus improving the influence of external uncertainties. The Eu-complex signal could be quenched after adding an amount of Cu . The ZIF-8 could enrich the target analytes, which can amplify the fluorescence signal due to the good adsorption properties of the ZIF-8. Based on above structural and compositional features, the detection limit of the nanoprobe is 0.1 nm for Cu , almost 2×10 times lower than the maximum allowable amount of Cu in drinking water, which constructed a platform for effective detection of Cu . Using the nanoprobe to detect Cu in aqueous solution is rapid and the probe still remained stable. Additionally, this sensor for the ratiometric fluorescence imaging of copper ions was also certified in real samples and live cells.

Encapsulation of Porphyrin‐Fe/Cu Complexes into Coordination Space for Enhanced Selective Oxidative Dehydrogenation of Aromatic Hydrazides

“…The average emission lifetime of photoexcited charge for HZ@TCPP-Fe was 21.83 ns, which was longer than that of HZ@TCPP-Fe/Cu (12.03 ns), suggesting that excited-state TCPP-Fe connected with Cu 2+ . [46] In HZ@TCPP-Fe/Cu, the TCPP-Fe/Cu bimetallic sites contained two five-coordinated copper cations that are bridged in a paddle-wheel-type configuration and to which the TCPP-Fe ligands were coordinated in a bidentate bridging fashion. [47][48][49] In N 2 adsorption and desorption isotherms, compared with ZIF-67, ZIF-67@TCPP-Fe displayed a reduced BET (Brunauer−Emmett−Teller) surface area from 1557 to 1475 m 2 g −1 , due to the mass contributions from TCPP-Fe molecule (Figure 3d).…”

“…The average emission lifetime of photoexcited charge for HZ@TCPP‐Fe was 21.83 ns, which was longer than that of HZ@TCPP‐Fe/Cu (12.03 ns), suggesting that excited‐state TCPP‐Fe connected with Cu 2+ . [ 46 ]…”

Recent Advances in Preparation and Applications of Magnetic Framework Composites

“…Based on the fluorescent probe sensing, Lu′s group developed a dual‐emission fluorescent MOFs by encapsulating the fluorescein isothiocyanat and Eu III complex functionalized Fe 3 O 4 into the ZIF‐8 for ultrasensitive and rapid ratiometric detection of Cu 2+ . The use of the porous structure of ZIF‐8 as a protective layer not only prevents agglomeration of the nanoparticles, but also enriches the analyte, thereby amplifying the fluorescent signal, so that the nanoprobe has good sensitivity and selectivity for detection of Cu 2+ .…”

Enhanced fluorescent effect of graphitic C3N4@ZIF-8 nanocomposite contribute to its improved sensing capabilities

“…Thus, ZIF-8 encapsulated AlQ 3 (tris(8-hydroxyquinoline)-aluminium), FITC (uorescein isothiocyanate) and Eu(III)-complex-functionalized Fe 3 O 4 , and Zn 2 GeO 4 :Mn 2+ nanorods were reported as a luminescent ions sensor. [20][21][22] Recently, graphitic carbon nitride (g-C 3 N 4 ) has attracted much attention due to its decisive advantages such as easy preparation, high thermal stability, high visible photocatalysis activity, and high water splitting activity. [23][24][25] Fluorescent g-C 3 N 4 quantum dots used for detecting heavy metal ions have been reported very recently.…”