A large Stokes shift NIR fluorescent probe for visual monitoring of mitochondrial peroxynitrite during inflammation and ferroptosis and in an Alzheimer's disease model.

The excessive formation of peroxynitrite (ONOO-) in mitochondria has been implicated in various pathophysiological processes and diseases. However, owing to short emission wavelengths and small Stokes shifts, previously reported fluorescent probes pose significant challenges for mitochondrial ONOO- imaging in biological systems. In this study, a near-infrared (NIR) fluorescent probe, denoted as DCO-POT, is designed for the visual monitoring of mitochondrial ONOO-, displaying a remarkable Stokes shift of 170 nm. The NIR fluorophore of DCO-CHO is released by DCO-POT upon the addition of ONOO-, resulting in off-on NIR fluorescence at 670 nm. This phenomenon facilitates the high-resolution confocal laser scanning imaging of ONOO- generated in biological systems. The practical applications of DCO-POT as an efficient fluorescence imaging tool are verified in this study. DCO-POT enables the fluorometric visualization of ONOO- in organelles, cells, and organisms. In particular, ONOO- generation is analyzed during cellular and organism-level (zebrafish) inflammation during ferroptosis and in an Alzheimer's disease mouse model. The excellent visual monitoring performance of DCO-POT in vivo makes it a promising tool for exploring the pathophysiological effects of ONOO-.

Osmotic Processor for Enabling Sensitive and Rapid Biomarker Detection via Lateral Flow Assays.

Urine is an attractive biospecimen for in vitro diagnostics, and urine-based lateral flow assays are low-cost devices suitable for point-of-care testing, particularly in low-resource settings. However, some of the lateral flow assays exhibit limited diagnostic utility because the urinary biomarker concentration is significantly lower than the assay detection limit, which compromises the sensitivity. To address the challenge, we developed an osmotic processor that statically and spontaneously concentrated biomarkers. The specimen in the device interfaces with the aqueous polymer solution via a dialysis membrane. The polymer solution induces an osmotic pressure difference that extracts water from the specimen, while the membrane retains the biomarkers. The evaluation demonstrated that osmosis induced by various water-soluble polymers efficiently extracted water from the specimens, ca. 5-15 ml/h. The osmotic processor concentrated the specimens to improve the lateral flow assays' detection limits for the model analytes-human chorionic gonadotropin and SARS-CoV-2 nucleocapsid protein. After the treatment via the osmotic processor, the lateral flow assays detected the corresponding biomarkers in the concentrated specimens. The test band intensities of the assays with the concentrated specimens were very similar to the reference assays with 100-fold concentrations. The mass spectrometry analysis estimated the SARS-CoV-2 nucleocapsid protein concentration increased ca. 200-fold after the osmosis. With its simplicity and flexibility, this device demonstrates a great potential to be utilized in conjunction with the existing lateral flow assays for enabling highly sensitive detection of dilute target analytes in urine.

Exosome Processing and Characterization Approaches for Research and Technology Development.

Exosomes are extracellular vesicles that share components of their parent cells and are attractive in biotechnology and biomedical research as potential disease biomarkers as well as therapeutic agents. Crucial to realizing this potential is the ability to manufacture high-quality exosomes; however, unlike biologics such as proteins, exosomes lack standardized Good Manufacturing Practices for their processing and characterization. Furthermore, there is a lack of well-characterized reference exosome materials to aid in selection of methods for exosome isolation, purification, and analysis. This review informs exosome research and technology development by comparing exosome processing and characterization methods and recommending exosome workflows. This review also provides a detailed introduction to exosomes, including their physical and chemical properties, roles in normal biological processes and in disease progression, and summarizes some of the on-going clinical trials.

Simultaneous visualization and quantification of copper (II) ions in Alzheimer's disease by a near-infrared fluorescence probe.

The abnormal accumulation of copper ions (Cu2+) is considered to be one of the pathological factors of Alzheimer's disease (AD), but the internal relationship between Cu2+ and AD progression is still not fully clear. In this work, a sensitive and selective near-infrared fluorescent copper ion probe (DDP-Cu) was designed for quantification and visualization of Cu2+ level in lysates, living cells, living zebrafish and brain tissues of drosophila and mice with AD. By using this probe, we demonstrated that the content of Cu2+ in the brains of AD mice and drosophila enhanced nearly 3.5-fold and 4-fold than that of normal mice and drosophila, respectively. More importantly, pathogenesis analysis revealed that elevated Cu2+ led to changes in factors closely associated with AD, such as the increasing of reactive oxygen species(ROS), the aggregation of amyloid-ß protein (Aß) and nerve cell cytotoxicity. These findings could promote the understanding of the roles between Cu2+ and AD.

A turn-on red-emitting fluorescent probe for determination of copper(II) ions in food samples and living zebrafish.

Herein, we developed a turn-on red-emitting fluorescent probe for the sensitive and selective detection of copper ions (Cu2+) in food samples and living zebrafish. The probe employs a hemicyanine scaffold as the fluorophore and a 2-pyridinecarbonyl group as the recognition receptor and quenching moiety. The 2-pyridinecarbonyl moiety can be specifically cleaved by Cu2+ and results in an approximately 18-fold fluorescence enhancement of the probe, thereby providing a fluorescence turn-on assay for Cu2+. Additionally, the probe exhibited excellent selectivity, high sensitivity, a broad linear relationship (0.020 to 8.0 µM), and a low limit of detection (4.0 nM, S/N = 3) for Cu2+. Concomitantly, the probe exhibited satisfactory analytical performance when used with actual food samples. Moreover, the probe could be used for in situ determination of Cu2+ in both living plant tissues and in living zebrafish.

Catalpol inhibits the proliferation, migration and metastasis of HCC cells by regulating miR­140­5p expression.

Hepatocellular carcinoma (HCC) is a frequent malignant tumor. Catalpol is a Chinese medicine extract with a number of pharmacologically active properties. The present study aimed to investigate the effects and mechanisms of catalpol in HCC. HCC cells were treated with catalpol in the presence or absence of microRNA (miR)­140­5p inhibitor, and assays to determine cell viability, proliferation, invasion and migration were performed. Reverse transcription­quantitative PCR and western blotting were performed to determine the mRNA and protein expression levels of miR­140­5p, vimentin, N­Cadherin and E­Cadherin. Moreover, cells were treated with catalpol in the absence or presence of transforming growth factor (TGF)­ß1, and the cell morphology was observed under a microscope. The results demonstrated that catalpol inhibited cell proliferation, invasion and migration, and decreased the expression levels of vimentin and N­cadherin, but increased the expression levels of E­cadherin and miR­140­5p. Catalpol inhibited morphological changes in epithelial­mesenchymal transformation (EMT) of cells induced by TGF­ß1. Following inhibition of miR­140­5p expression, the proliferation, invasion and migration of HCC cells were promoted, E­cadherin expression was decreased, and the levels of vimentin and N­cadherin were increased. The miR­140­5p inhibitor effectively reversed the inhibitory effect of catalpol on cell proliferation, invasion and migration. Thus, the results suggested that the antitumor potential of catalpol in HCC may be exerted by regulating the expression of miR­140­5p to inhibit proliferation, invasion, migration and EMT of HCC cells.

Hierarchical MoS2 @TiO2 Heterojunctions for Enhanced Photocatalytic Performance and Electrocatalytic Hydrogen Evolution.

Hierarchical MoS2 @TiO2 heterojunctions were synthesized through a one-step hydrothermal method by using protonic titanate nanosheets as the precursor. The TiO2 nanosheets prevent the aggregation of MoS2 and promote the carrier transfer efficiency, and thus enhance the photocatalytic and electrocatalytic activity of the nanostructured MoS2 . The obtained MoS2 @TiO2 has significantly enhanced photocatalytic activity in the degradation of rhodamine B (over 5.2 times compared with pure MoS2 ) and acetone (over 2.8 times compared with pure MoS2 ). MoS2 @TiO2 is also beneficial for electrocatalytic hydrogen evolution (26 times compared with pure MoS2 , based on the cathodic current density). This work offers a promising way to prevent the self-aggregation of MoS2 and provides a new insight for the design of heterojunctions for materials with lattice mismatches.

131I-labeled monoclonal antibody targeting neuropilin receptor type-2 for tumor SPECT imaging.

As a co-receptor for vascular endothelial growth factor­3 (VEGF­3), neuropilin receptor type­2 (NRP­2) plays a central role in lymphangiogenesis and angiogenesis. Recently, mounting data of evidence show that NRP­2 is overexpressed in several human cancers, and its overexpression is often associated with poor prognosis. Therefore, it is necessary for us to develop an affinity reagent for noninvasive imaging of NRP­2 expression because it may be possible to provide early cancer diagnosis, more accurate prognosis, and better treatment planning. Due to their high affinity, and specificity, monoclonal antibodies (mAbs) have been considered attractive candidates for targeted cancer therapy and diagnostics. We recently generated and validated a monoclonal antibody that specifically binds NRP­2 b1b2 domain with no cross­reactivity to NRP­1 b1b2 domain, also known to be overexpressed in a variety of cancers. Here, we developed a single photon emission computed tomography (SPECT) probe for imaging NRP­2- positive tumors. Anti­NRP­2 monoclonal antibodies were prepared by hybridomas and were labeled with iodine­131 by chloramine­T method. The in vitro physicochemical properties of 131I­anti­NRP­2 mAb was determined. Binding affinity and specificity of 131I­anti­NRP­2 mAb to NRP­2 were assessed using human lung adenocarcinoma A549 cells. Biodistribution and SPECT studies were performed in mice bearing A549 tumor xenografts to evaluate the in vivo performance of 131I­anti­NRP­2 mAb. The preparation of anti­NRP­2 mAb was completed successfully by hybridoma with high purity (>95%) and specific for NRP­2 b1b2 domain, but not NRP­1 b1b2 domain. The radiosynthesis of 131I­anti­NRP­2 mAb was completed successfully within 60 min with high labelling efficiency (94.69±3.63%), and radiochemical purity (98.56±0.48%). The resulting probe, 131I­anti­NRP­2 mAb displayed excellent stability in PBS solution during 24-72 h. 131I­anti­NRP­2 mAb showed high binding affinity with A549 cells (96.6±1.44 nM). In vivo biodistribution and SPECT studies demonstrated targeting of A549 glioma xenografts was NRP­2 specific. The tumor uptake was 5.86±0.27% ID/g at 6 h, and kept at high level of 4.64±0.82% ID/g at 72 h­post­injection. The tumor to contralateral muscle ratio (T/NT) was 2.08±0.33 at 6 h, and reached the highest level of 3.83±0.18 at 72 h after injection. SPECT imaging studies revealed that 131I­anti­NRP­2 mAb could clearly identify A549 tumors with good contrast, especially at 48­72 h after injection. In conclusion, this study demonstrates that 131I­anti­NRP­2 mAb exhibited highly selective uptake in NRP­2­expressing tumors, and may provide a promising SPECT probe for imaging NRP­2 positive tumors.

[Field evaluation of a novel plant molluscicide "Luo-wei" against Oncomelania hupensis IV molluscicidal effect in field of river beach in Dongzhi County, Anhui Province].

OBJECTIVE: To evaluate the field effect of the plant molluscicide "Luo-wei" (tea-seed distilled saponins, TDS) against the snail Oncomelania hupensis in the river beach in Anhui Province. METHODS: The immersing and spraying experiments were carried out in the river beach in Dongzhi County, Anhui Province, to assess the molluscicidal effect of 4% TDS comparing with 50% wettable powder of niclosamide ethanolamine salt (WPN). The chi(2) test or Fish's exact test was used to examine the differences between or among the molluscicidal effects by different environments, molluscicides, application methods, or days after the intervention. Meanwhile, the cost-effectiveness of the two molluscicides was analyzed. RESULTS: After 1, 2 , 3 d and 7 d of the immersion, the snail death rates in both TDS group and WPN group increased gradually, the snail death rates in the two groups after immersing for 7 d were 94.62% and 99.24%, respectively, and there was no significant difference between them ( chi(2) = 3.30, P > 0.05). After 1 , 3 , 7 d and 15 d of spraying, the snail death rates were 70.82%, 79.75%, 85.11% and 91.65% in the TDS group, and 77.71%, 84.27%, 91.90% and 95.58% in the WPN group, respectively, and the differences among the snail death rates of the two groups at each time point were statistically significant (all P values < 0.05). The costs of spraying were 316.71 yuan per 100 m2 for TDS and 309.71 for WPN. CONCLUSIONS: The molluscicidal effect of TDS has reached the requirements of national standard on nature source pesticides in the river beach of the middle and lower reaches of the Yangtze River. It is necessary to further evaluate its cost-effectiveness in large-scale field experiments in the future.