The level of circulating tumor cells (CTCs) plays a critical role in tumor metastasis and personalized therapy, but it is challenging for highly efficient capture and detection of CTCs because of the extremely low concentration in peripheral blood. Herein, we report near-infrared fluorescent AgS nanodot-based signal amplification combing with immune-magnetic spheres (IMNs) for highly efficient magnetic capture and ultrasensitive fluorescence labeling of CTCs. The near-infrared fluorescent AgS nanoprobe has been successfully constructed through hybridization chain reactions using aptamer-modified AgS nanodots, which can extremely improve the imaging sensitivity and reduce background signal of blood samples. Moreover, the antiepithelial-cell-adhesion-molecule (EpCAM) antibody-labeled magnetic nanospheres have been used for highly capture rare tumor cells in whole blood. The near-infrared nanoprobe with signal amplification and IMNs platform exhibits excellent performance in efficient capture and detection of CTCs, which shows great potential in cancer diagnostics and therapeutics.

We introduce the synthesis strategy, photoluminescence features and biological applications of TMD QDs.

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In this work, a novel phenomenon was discovered that the fluorescence intensity of silver sulfide quantum dots (AgS QDs) could be enhanced in the presence of rare earth ions through aggregation-induced emission (AIE). Based on the strong coordination between rare earth ions and F, a facile and label-free strategy was developed for the detection of F in living cells. AgS QDs were synthesized using 3-mercaptopropionic acid as sulfur source and stabilizer in aqueous solution. The near infrared (NIR) emitting QDs exhibited excellent photostalilty, high quantum yield and low toxic. Interestingly, the fluorescence intensity of QDs was obviously enhanced upon the addition of various rare earth ions, especially in the presence of Gd. The AIE mechanism was proved via the TEM, zeta potential and dynamic light scattering analysis. Moreover, the coordination between rare earth ions and F could lead to the quenching of fluorescence QDs due to the weakening the AIE. Based on these findings, we developed a highly sensitive and selective method for detection of F. The label-free NIR fluorescence probe was successfully used for F bioimaging in live cells.

A nanosized Tb-MOF with a boronic acid ligand can be used for the highly sensitive detection and scavenging of ROS in living cells.

The authors describe an environmentally friendly and fast (~14 min) method for the synthesis of homogeneously distributed fluorescent polydopamine nanodots (PDA-NDs) using KMnO as the oxidant. Alkaline phosphatase (ALP) catalyzes the hydrolysis of ascorbic acid 2-phosphate to release free ascorbic acid which undergoes an in-situ redox reaction with KMnO. Depending on the activity of ALP, more or less KMnO is consumed, and this affects the formation of the PDA-NDs. Based on this finding, a sensitive method was worked out to quantify the activity of ALP via real-time formation of fluorescent PDA-NDs. The fluorometric signal (best measured at excitation/emission peaks of 390/500 nm) is linear in the 1 to 50 mU·mL ALP activity range, and the limit of the detection is as low as 0.94 mU·mL (based on 3 σ/m). The method was successfully applied to the determination of ALP activity in spiked human serum and in MCF-7 cell lysates. It was also applied in a method to screen for inhibitors of ALP. Graphical abstract Schematic of a fluorometric method for the determination of alkaline phosphatase (ALP) activity. The method is based on the in-situ regulation of the formation of fluorescent polydopamine nanodots (PDA-NDs) through the competition between the KMnO-induced polymerization of dopamine and ALP-directed ascorbic acid 2-phosphate (Asc-2P) hydrolysis. AA: Ascorbic acid.

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High-valent metal-oxo (M–O, M = Fe, Mn, etc.) species are the well-known reaction intermediates that are responsible for a wide range of pivotal oxygenation and water oxidation in metalloenzymes. Though...