Integrating gold nanoclusters, folic acid and reduced graphene oxide for nanosensing of glutathione based on “turn-off” fluorescence

Abstract

Glutathione (GSH) is a useful biomarker in the development, diagnosis and treatment of cancer. However, most of the reported GSH biosensors are expensive, time-consuming and often require complex sample treatment, which limit its biological applications. Herein, a nanobiosensor for the detection of GSH using folic acid-functionalized reduced graphene oxide-modified BSA gold nanoclusters (FA-rGO-BSA/AuNCs) based on the fluorescence quenching interactions is presented. Firstly, a facile and optimized protocol for the fabrication of BSA/AuNCs is developed. Functionalization of rGO with folic acid is performed using EDC/NHS cross-linking reagents, and their interaction after loading with BSA/AuNCs is demonstrated. The formation of FA-rGO, BSA/AuNCs and FA-rGO-BSA/AuNCs are confirmed by the state-of-art characterization techniques. Finally, a fluorescence turn-off sensing strategy is developed using the as-synthesized FA-rGO-BSA/AuNCs for the detection of GSH. The nanobiosensor revealed an excellent sensing performance for the detection of GSH with high sensitivity and desirable selectivity over other potential interfering species. The fluorescence quenching is linearly proportional to the concentration of GSH between 0 and 1.75 µM, with a limit of detection of 0.1 µM under the physiological pH conditions (pH 7.4). Such a sensitive nanobiosensor paves the way to fabricate a “turn-on” or “turn-off” fluorescent sensor for important biomarkers in cancer cells, presenting potential nanotheranostic applications in biological detection and clinical diagnosis.

Origin of luminescence properties and synthetic methods for gold- and bimetallic gold-based nanomaterials

“…Wong et al modified the methodology utilizing a thermomixer for mixing BSA and HAuCl 4 solution, which is more advantageous compared to the earlier reported methods because of its short reaction time, higher quantum yield and mild conditions. 160 AuNCs were also synthesized using ligands besides the traditional ligands such as anti-Flt1 peptide (CGNQWFI, AF), as shown in Fig. 8.…”

Expanding the Scope of Nanobiocatalysis and Nanosensing: Applications of Nanomaterial Constructs

“…The glutathione, an antioxidant molecule strongly related to several types of cancer, competes with the BSA which leads to the photobleaching of the nanostructure. 93 …”

Advancements in 2D Materials Based Biosensors for Oxidative Stress Biomarkers

“…Real sample analysis using this sensor was however not demonstrated. 185 Ye and co-workers developed a FRET based system for the optical detection of 8-OHdG. The work reported the use of carbon dots modified nanoporous membrane as the fluorophore and Au@ZIF-8 nanoparticles as the quencher probe.…”

“…The sensor had a linear range from 0 to 1.75 μM. Real sample analysis using this sensor was however not demonstrated …”