A novel assembled nanobiosensor QDs-ConA-beta-CDs-AuNPs was designed for the direct determination of glucose in serum with high sensitivity and selectivity. The sensing approach is based on fluorescence resonance energy transfer (FRET) between CdTe quantum dots (QDs) as an energy donor and gold nanoparticles (AuNPs) as an energy acceptor. The specific combination of concanavalin A (ConA)-conjugated QDs and thiolated beta-cyclodextrins (beta-SH-CDs)-modified AuNPs assembles a hyperefficient FRET nanobiosensor. In the presence of glucose, the AuNPs-beta-CDs segment of the nanobiosensor is displaced by glucose which competes with beta-CDs on the binding sites of ConA, resulting in the fluorescence recovery of the quenched QDs. Experimental results show that the increase in fluorescence intensity is proportional to the concentration of glucose within the range of 0.10-50 muM under the optimized experimental conditions. In addition, the nanobiosensor has high sensitivity with a detection limit as low as 50 nM, and has excellent selectivity for glucose over other sugars and most biological species present in serum. The nanobiosensor was applied directly to determine glucose in normal adult human serum, and the recovery and precision of the method were satisfactory. The unique combination of high sensitivity and good selectivity of this biosensor indicates its potential for the clinical determination of glucose directly and simply in serum, and provides the possibility to detect low levels of glucose in single cells or bacterial cultures. Moreover, the designed nanobiosensor achieves direct detection in biological samples, suggesting the use of nanobiotechnology-based assembled sensors for direct analytical applications in vivo or in vitro.
To reduce the side effects of chemotherapy, nontoxic prodrugs activated by the tumor microenvironment are urgently required for use in cancer treatment. In this work, we developed prodrug 4 for tumor-targeting treatment and imaging of the anticancer drug release in vivo. Taking advantage of the high glutathione (GSH) concentration in cancer cells, the disulfide bond in prodrug 4 was cleaved, resulting in the release of an active anticancer drug and a near-infrared (NIR) fluorescence dye turn-on. Furthermore, contrast to the free anticancer drug, the prodrug exhibited higher cytotoxicity to hepatoma cells than that to normal HL-7702 cells. Thus, prodrug 4 is a promising platform for specific tumor-activatable drug delivery system, because of its favorable features of in situ and in vivo monitoring of the drug release and therapeutic efficacy.
Alterations of cellular redox status are closely associated with physiological and pathological processes.Glutathione (GSH) and H 2 O 2 should be the most representative redox couple in living cells. However, up to now, there is no way to reversibly detect GSH/H 2 O 2 . In this report, a near-infrared (NIR) fluorescent probe (Cy-O-Eb) for monitoring the changes of GSH/H 2 O 2 levels in vivo was developed based on switching on-off a five-membered ring involved in ebselen. This probe could reversibly respond to GSH and H 2 O 2 with high selectivity, sensitivity and mitochondrial targeting. It was successfully used to monitor the changes of redox status during apoptosis and the H 2 O 2 changes at the wound margin in zebrafish larvae. Thus, the probe would provide an ideal tool for monitoring redox status changes and studying molecular events involved in redox regulation.
A highly selective and sensitive near-infrared (NIR) fluorescence probe (Cy-NO2) for imaging nitroreductase was developed and was successfully applied to investigating the relationship between epithelial-mesenchymal transitions (EMTs) in tumour progression and intracellular hypoxic level.
Gold nanoparticles (Au NPs) assembled through Au-S covalent bonds have been widely used in biomolecule-sensing technologies. However, during the process, detection distortions caused by high levels of thiol compounds can still significantly influence the result and this problem has not really been solved. Based on the higher stability of Au-Se bonds compared to Au-S bonds, we prepared selenol-modified Au NPs as an Au-Se nanoplatform (NPF). Compared with the Au-S NPF, the Au-Se NPF exhibits excellent anti-interference properties in the presence of millimolar levels of glutathione (GSH). Such an Au-Se NPF that can effectively avoid detection distortions caused by high levels of thiols thus offers a new perspective in future nanomaterial design, as well as a novel platform with higher stability and selectivity for the in vivo application of chemical sensing and clinical therapies.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.