Fluorescence Modulation by Absorbent on Solid Surface: An Improved Approach for Designing Fluorescent Sensor

Abstract

Inner filter effect (IFE), a well-known phenomenon of fluorescence quenching resulting from absorption of the excitation or emission light of luminescent species by absorbent, has been used as a smart approach to design fluorescent sensors, which are characterized by the simplicity and flexibility with high sensitivity. However, further application of IFE-based sensors in complex environment is hampered by the insufficient IFE efficiency and low sensitivity resulting from interference of the external environment. In this paper, we report that IFE occurring on a solid substrate surface would solve this problem. As a proof of concept, a fluorescent sensor for intracellular biothiols has been developed on the basis of the absorption of a newly designed thiols-specific chromogenic probe (CP) coupled with the use of a thiols-independent fluorophore, rhodamine 6G (R6G), operative on the IFE on graphene oxide (GO). To construct an efficient IFE system, R6G was covalently attached to GO, and the CP molecules were adsorbed on the surface of R6G-GO via π-π stacking interaction. The reaction of thiols with CP on R6G-GO decreases the absorption of CP, resulting in the increase of the intensity of R6G fluorescence. The results showed that the IFE efficiency, sensitivity, and dynamic response time of R6G-GO/CP for biothiols could be significantly improved compared with R6G/CP, and furthermore, R6G-GO/CP functioned under complex system and could be used for assaying biothiols in living cells and in human serum samples. This new strategy would be general to explore the development of more effective IFE-based sensors for other analytes of interest.

Applications of graphene and its derivatives in intracellular biosensing and bioimaging

“…76 Aside from ATP and GTP, graphene and its derivatives have been widely implemented for the intracellular determination of other analytes such as biothiols, L-carnitine, amino acid, paraquat etc. Yang's group 77 developed a fluorescence sensor for intracellular biothiols based on a GO platform functionalized by a thiol-specific chromogenic probe (CP) and thiolindependent fluorophore Rhodamine 6G (R6G). In this strategy, R6G was covalently attached to GO, and the CP molecules were adsorbed on the surface of R6G-GO via π-π stacking interactions.…”

The luminescence inner filter effect of Mn2+-doped (ZnS)2·octylamine inorganic/organic hybrid thin films and their sensor application for environmental contaminants

“…Since the pioneered work of Cary in 1984, [3] IFE-based fluorescence sensors have witnessed a fast development to detect various chemical and biological analytes, ranging from meal ions/anions to protease, and single nucleotide polymorphisms. [4][5][6][7][8] The inorganic/organic (I/O) hybrid compounds are a kind of composites with the inorganic and organic component combination at atomic level, which have the advantages in inorganic rigidity, stability and organic lightweight, flexibility, processability, diversity. [9,10] Furthermore, they possess unique electronic/optical properties being attributed to their individual constituents, and have become new-generational functional materials and research focus of materials sciences for more than 30 years.…”

Diketopyrrolopyrrole-Based Ratiometric/Turn-on Fluorescent Chemosensors for Citrate Detection in the Near-Infrared Region by an Aggregation-Induced Emission Mechanism

“…Currently, fluorescent sensors as a novel technology have been widely used in testing ions, − small molecules, and as imaging , analysts in vivo due to their excellent sensitivity, visualization, easy operation, and lower requirement of equipment. In recent years, some colorimetric and fluorescent sensors for detection of citrate have been reported, − but many of them are based on an indicator-displacement assay (IDA), which generally contains two steps. , First, the fluorescent sensors can form complexes with metals resulting in changes in fluorescent signals.…”