Selective Zinc(II)‐Ion Fluorescence Sensing by a Functionalized Mesoporous Material Covalently Grafted with a Fluorescent Chromophore and Consequent Biological Applications

Abstract

A highly ordered 2D‐hexagonal mesoporous silica material is functionalized with 3‐aminopropyltriethoxysilane. This organically modified mesoporous material is grafted with a dialdehyde fluorescent chromophore, 4‐methyl‐2,6‐diformyl phenol. Powder X‐ray diffraction, transmission electron microscopy, N2 sorption, Fourier transform infrared spectroscopy, and UV‐visible absorption and emission have been employed to characterize the material. This material shows excellent selective Zn2+ sensing, which is due to the fluorophore moiety present at its surface. Fluorescence measurements reveal that the emission intensity of the Zn2+‐bound mesoporous material increases significantly upon addition of various concentrations of Zn2+, while the introduction of other biologically relevant (Ca2+, Mg2+, Na+, and K+) and environmentally hazardous transition‐metal ions results in either unchanged or weakened intensity. The enhancement of fluorescence is attributed to the strong covalent binding of Zn2+, evident from the large binding constant value (0.87 × 104 M−1). Thus, this functionalized mesoporous material grafted with the fluorescent chromophore could monitor or recognize Zn2+ from a mixture of ions that contains Zn2+ even in trace amounts and can be considered as a selective fluorescent probe. We have examined the application of this mesoporous zinc(II) sensor to cultured living cells (A375 human melanoma and human cervical cancer cell, HeLa) by fluorescence microscopy.

Synthesis of Hollow‐flower‐ball‐like Cd4(OH)5Cl3 Using Microwave Irradiation Method

“…In these isotherms, the adsorption amount gradually increased for Cd 4 (OH) 5 Cl 3 between p/p 0 ＝0.025-0.6, which may be attributed to the classical capillary condensation of the mesopores. [21][22][23] The BET surface area and mesopore volume for Cd 4 (OH) 5 Cl 3 were 24.8254 m 2 •g -1 and 0.108716 cm 3 •g -1 , respectively. The morphology of the product was examined using SEM.…”

Kompostite auf Basis von Zeolithen oder geordnet mesoporösen Oxiden für Anwendungen in der Photonik und Sensorik

“…Mit diesem System können in lebenden Zellen, Gewebe und Mikroorganismen sehr exakte pHWert-Messungen vorgenommen werden [76]. Weiterhin ist über Veränderungen des Fluoreszenzsignals eines an den Wänden von mesoporösem SiO 2 verankerten und dann in Zellen eingeschleusten Chromophors auch die Detektion von Metallkationen in lebenden Zellen möglich, wie Bhaumik und Mitarbeiter beispielhaft für den Nachweis von Zink-Ionen zeigten [77]. Dabei kommt dem Nachweis zu Gute, dass mesoporöse Silika-Materialien, speziell wenn sie zusätzlich mit Thiolgruppen funktionalisiert sind, sehr hohe Aufnahmekapazitäten für bestimmte Schwermetallionen aufweisen [78,79].…”

The Zinc‐Dependent Fluorescence of a Synthetic GFP‐Like Chromophore in Organic Solvents

“…Although many fluorescent indicators for Zn 2+ have been designed and synthesized, none can perfectly satisfy all the requirements (see refs. [1,2] for the requirements for Zn 2+ indicators). Thus, efforts to design new Zn 2+ probes should be encouraged.…”

“…Cellular Zn 2+ varies from the nanomolar range to about 0.3 mm. [1,2] It plays diverse roles in multiple biological processes. [3][4][5][6][7][8] A disorder of the Zn 2+ metabolism is closely associated with many severe neurological diseases.…”