Highly sensitive and selective ratiometric fluorescence detection of ATP using aptamer-functionalized FeO nanozymes with tunable activity.

Herein, a highly sensitive and selective ratiometric fluorescence platform was constructed for probing adenosine triphosphate (ATP) for the first time by using magnetic FeO nanozymes that were modified by ATP-specific aptamer labeled with 7-Amino-4-methyl-3-coumarinylacetic acid (Apt-AMCA) to yield FeO@Apt-AMCA. It was discovered that the incorporation of Apt-AMCA greatly enhance the peroxidase-like activity of FeO nanozymes, which might catalyze more o-phenylenediamine (OPD) substrates into fluorescent oxidized OPD (DAP) with a emission of 560 nm. More importantly, upon ATP addition, Apt-AMCA could potentially be released from FeO@Apt-AMCA because of Apt-target binding and the competition between ATP and Apt.

Near-infrared II cyanine fluorophores with large stokes shift engineered by regulating respective absorption and emission.

Fluorescence bioimaging in the near-infrared II window is a promising area due to its deep tissue penetration and high contrast. However, efficient design strategies for near-infrared II fluorophores with large Stokes shifts are still scarce. Here, we develop a series of near-infrared II fluorophores (termed VIPIs) with large Stokes shifts (167-260 nm in chloroform) by conjugating p-aminostyryl to hemicyanines.

A near-infrared fluorescence probe for sensing mitochondrial viscosity in cells and mice.

Mitochondria play a critical role in providing energy to maintain cellular physiological functions. The viscosity in mitochondria is one of the important indicators of mitochondrial microenvironment. When mitochondrial viscosity increases, it often indicates the occurrence or development of certain diseases.

Photoinduced Synergism of Ferroptosis/Pyroptosis/Oncosis by an O-Independent Photocatalyst for Enhanced Tumor Immunotherapy.

Due to O dependence, hypoxia-induced apoptosis resistance, and immunosuppressive microenvironment, the effect of traditional photodynamic therapy toward hypoxic solid tumors is severely limited. Herein, we report an O-independent photocatalyst (EBSe) for tumor immunotherapy potentiation via synergism of near-infrared (NIR) light-induced ferroptosis/pyroptosis/oncosis. Simple Se and ethyl modifications on methylene blue (MB) endow EBSe with a remarkable phototoxicity enhancement (>2500 folds) and an excellent phototoxicity index (PI > 32,000) to 4T1 cells under hypoxia.

Carnivorous fishes can possess higher mercury levels than omnivorous fishes: A selective detection and efficient removal strategy for mercury using magnetic melamine-platinum composites fabricated by supermolecular self-assembly.

Mercury (II) ion (Hg) as highly toxic heavy metal may be accumulated in aquatic ecosystems and animals species so as to enter human body to conduct health harm. To ensure the safety of fishes food, hence, it is of great interest to evaluate the Hg levels in different kinds of fishes as well as Hg removal in aquaculture tailwater. In this article, a selective colormetric detection and efficient removal strategy has been developed for Hg ions by the controlled supermolecular self-assembly of melamine (MA)-platinum (Pt) composites onto mesoporous FeO carriers.

Facile fabrication of biocompatible carbon dots from egg white by one-step neutralization heat reaction: a capillary array-based fluorimetric strategy for high-throughput detection of total iron ions in fish blood.

Water-soluble and biocompatible protein carbon dots (P-CDs) were simply prepared from egg white by a rapid one-step neutralization heat reaction. Unexpectedly, the thus-fabricated P-CDs could present excitation-dependent tunable fluorescence that could be quenched specifically by Fe and Fe ions with obvious color changes. A high-throughput fluorimetric platform was thereby developed by coating the P-CDs onto a capillary array for detection of total iron ions in fish blood samples, with a linear concentration range of 0.

An Oxazine-Based Fluorogenic Probe with Changeable π-Conjugation to Eliminate False-Positive Interference of Albumin and Its Application to Sensing Aminopeptidase N.

Many fluorophores/probes suffer from the interference of albumin in biosystems. Herein, we propose an effective strategy to overcome this interference by virtue of both an albumin-insensitive fluorophore and its changeable π-conjugation, and demonstrate the strategy by designing an oxazine-based fluorogenic probe for aminopeptidase N (APN). The modification on the N atom in the oxazine fluorophore with alanine through a cleavable linker locks the resulting probe in a non-conjugated, colorless and non-fluorescent state, so the non-specific interaction of albumin produces no spectroscopic response.

A fluorimetric test strip with suppressed "Coffee Ring Effect" for selective mercury ion analysis.

Nowadays, test strips are widely applied, but their use is mostly limited to the qualitative or half-quantitative analysis of targets. The main reason for their limited use is the "Coffee Ring Effect" (CRE) of probe materials, which leads to a heterogeneous probe distribution and poor testing reproducibility and sensitivity. In the present work, a fluorescent test strip was fabricated with a suppressed CRE of silver nanocluster (AgNC) probes coated by gelatin (Gel) under vacuum-aided fast lyophilization.

Bleomycin-Fe(II) agent with potentiality for treating drug-resistant H1N1 influenza virus: A study using electrochemical RNA beacons.

Rapid emergence of new strains of drug-resistant H1N1 influenza viruses calls for effective drugs for the controls prior to their outbreaks. In the present work, electrochemical H1N1 RNA beacons have been newly designed for exploring the potentiality of an anticancer agent of Bleomycin (BLM) with Fe (ΙΙ) ions (BLM-Fe(ΙΙ)) alternatively the treatment of drug-resistant H1N1 strains with H274Y gene mutation. Herein, biotinylated (-) ssRNA of H1N1 virus and its complementary (+) ssRNA were labeled with electrochemical signal probes of ferrocene and anthraquinone, respectively.

A molecular approach to rationally constructing specific fluorogenic substrates for the detection of acetylcholinesterase activity in live cells, mice brains and tissues.

Acetylcholinesterase (AChE) is an extremely critical hydrolase tightly associated with neurological diseases. Currently, developing specific substrates for imaging AChE activity still remains a great challenge due to the interference from butyrylcholinesterase (BChE) and carboxylesterase (CE). Herein, we propose an approach to designing specific substrates for AChE detection by combining dimethylcarbamate choline with a self-immolative scaffold.

Water-Soluble Near-Infrared Fluorescent Probes for Specific Detection of Monoamine Oxidase A in Living Biosystems.

Monoamine oxidase (MAO) has two isomers (A and B), and the analysis of each one in biological samples is of great potential in studying MAO-related diseases. However, specific detection and imaging of MAO-A in cells and are still a great challenge at present due to the relative lack of suitable near-infrared (NIR) fluorescent probes. In this work, two new NIR fluorescent probes, Rma-1 and Rma-2, have been developed for the analysis of MAO-A in living biosystems.

Increase of tyrosinase activity at the wound site in zebrafish imaged by a new fluorescent probe.

Tyrosinase plays a pivotal role in the hyperpigmentation of wounds. Here, we develop a new fluorescent probe and with it, we reveal an increase of tyrosinase activity at the wound site in zebrafish.

Design, Synthesis, and Application of a Small Molecular NIR-II Fluorophore with Maximal Emission beyond 1200 nm.

Small molecular fluorophores in the second near-infrared window (NIR-II) have aroused much interest because of their excellent performance. Herein, a new small molecular NIR-II fluorophore, FM1210, with maximal emission beyond 1200 nm is reported. Compared to the corresponding control fluorophore CF1065, FM1210 exhibits an increase of 145 nm in the emission maximum, which is ascribed to the simultaneous introduction of both a Se atom and amino groups into the benzo[1,2-:4,5-']bis([1,2,5]thiadiazole) skeleton.

Label-Free Sensing of Human 8-Oxoguanine DNA Glycosylase Activity with a Nanopore.

Human 8-oxoguanine DNA glycosylase (hOGG1) plays a significant role in maintaining the genomic integrity of living organisms for its capability of repairing DNA lesions. Accurate detection of hOGG1 activity would greatly facilitate the screening and early diagnosis of diseases. In this work, we report a nanopore-based sensing strategy to probe the hOGG1 activity by employing the enzyme-catalytic cleavage reaction of DNA substrate.

Fluorimetric Mercury Test Strips with Suppressed "Coffee Stains" by a Bio-inspired Fabrication Strategy.

A fluorimetric Hg test strip has been developed using a lotus-inspired fabrication method for suppressing the "coffee stains" toward the uniform distribution of probe materials through creating a hydrophobic drying pattern for fast solvent evaporation. The test strips were first loaded with the model probes of fluorescent gold-silver nanoclusters and then dried in vacuum on the hydrophobic pattern. On the one hand, here, the hydrophobic constraining forces from the lotus surface-like pattern could control the exterior transport of dispersed nanoclusters on strips leading to the minimized "coffee stains".

Nanopore-Based Selective Discrimination of MicroRNAs with Single-Nucleotide Difference Using Locked Nucleic Acid-Modified Probes.

The accurate discrimination of microRNAs (miRNAs) with highly similar sequences would greatly facilitate the screening and early diagnosis of diseases. In the present work, a locked nucleic acid (LNA)-modified probe was designed and used for α-hemolysin (α-HL) nanopore to selectively and specifically identify miRNAs. The hybridization of the LNA probe with the target miRNAs generated unique long-lived signals in the nanopore thus facilitated an accurate discrimination of miRNAs with similar sequences, even a single-nucleotide difference.