Fluorophore Label-Free Light-up Near Infrared Deoxyribonucleic Acid Nanosensor for Monitoring Extracellular Potassium Levels.

Fluorescent DNA nanosensors have been widely used due to their unique advantages, among which the near-infrared (NIR) imaging mode can provide deeper penetration depth and lower biological background for the nanosensors. However, efficient NIR quenchers require ingenious design, complex synthesis, and modification, which severely limit the development of NIR DNA nanosensors. Label-free strategies based on G-quadruplex (G4) and NIR G4 dyes were first introduced into in situ extracellular imaging, and a novel NIR sensing strategy for the specific detection of extracellular targets is proposed. The strategy avoids complex synthesis and site-specific modification by controlling the change of the NIR signal through the formation of a G4 nanostructure. A light-up NIR DNA nanosensor based on potassium ion (K+)-sensitive G4 chain PS2.M was constructed to verify the strategy. PS2.M forms a stable G4 nanostructure in the presence of K+ and activates the NIR G4 dye CSTS, thus outputting NIR signals. The nanosensor can rapidly respond to K+ with a linear range of 5-50 mM and has good resistance to interference. The nanosensor with cholesterol can provide feedback on the changes in extracellular K+ concentration in many kinds of cells, serving as a potential tool for the study of diseases such as epilepsy and cancer, as well as the development of related drugs. The strategy can be potentially applied to the NIR detection of a variety of extracellular targets with the help of functional DNAs such as aptamer and DNAzyme.

Recent advances in inspection technologies of food safety health hazards for fish and fish products.

The development of reliable and sensitive detection methods is essential for addressing the escalating concerns surrounding fish and fish products, driven by increasing market demands. This comprehensive review presents recent advances in detection approaches, specifically focusing on microplastic, biological, and chemical hazards associated with these products. The overview encompasses 21 distinct detection methods, categorized based on the type of hazard they target. For microplastic hazards, six methods are visual, spectroscopic, and thermal analyses. Biological hazard identification relies on six approaches employing nucleic-acid sequence, immunological, and biosensor technologies. The investigation of chemical hazards encompasses ten methods, including chromatography, spectroscopy, mass spectrometry, immunological, biosensor, and electrochemical techniques. The review provides in-depth insights into the basic principles, general characteristics, and the recognized advantages and disadvantages of each method. Moreover, it elaborates on recent advancements within these methodologies. The concluding section of the review discusses current challenges and outlines future perspectives for these detection methods. Overall, this comprehensive summary not only serves as a guide for researchers involved in fish safety and quality control but also emphasizes the significance of staying abreast of evolving detection technologies to ensure the continued safety of fish and fish products in response to emerging food safety hazards.

Anthropogenic particles in the muscle, gill, and gastrointestinal tract of marine fish sold for human consumption.

Contamination of marine fish with the widespread distribution of anthropogenic particles (APs) becomes increasingly severe, however, related research on the assessment of the occurrence of APs in the edible tissue of commercial fish is scarce. The objective of this study was to evaluate the features of APs pollution based on seven species of commercial marine fish (n = 12 per species) and investigate the accumulation of APs in different tissues of fish namely gill and gastrointestinal tract (GIT), and muscle. The results show that a total of 62 APs were detected in 33 out of 84 (39.3%) fresh fish samples using a micro-Raman spectrometer which in particular is characterized by a blue color, shape-like fiber, and size smaller than 0.5 mm. Among them, 47 (75.8%) particles were identified as pigments such as indigo, chrome yellow-orange, disperse yellow, and pigment black. The other 11 (17.7%) particles were plastic including polypropylene (PP), polyethylene terephthalate (PET), and polyacrylonitrile (PAN). And the rest 4 (6.5%) particles were anthropogenic cellulose fibers. Muscle tissue from six species of fish was detected to contain a total of 15 APs. Based on the total mean of APs found in fish muscle (0.018 AP items/g tissue) and on the consumption of fish in Malaysia (59 kg/capita/year), the estimated human intake of APs through fish consumption was 1062 AP items/year/capita. Considering that food consumption is an important route of human exposure to APs, it is suggested to add APs testing into the guidelines of food safety management systems and adopt mitigation measures to reduce the APs pollution in food.

Current status of food safety hazards and health risks connected with aquatic food products from Southeast Asian region.

Food safety issues associated with aquatic food products become more important with the increasing consumption and followed by its ongoing challenges. The objective of this paper is to review the food safety hazards and health risks related to aquatic food products for the Southeast Asian region. These hazards can be categorized as microplastics (MPs) hazard, biological hazards (pathogenic bacteria, biogenic amines, viruses, parasites), and chemical hazards (antimicrobial, formaldehyde, heavy metal). In different Southeast Asian countries, the potential health risks of aquatic food products brought by food hazards to consumers were at different intensity and classes. Among all these hazards, pathogenic bacteria, antimicrobials, and heavy metal were a particular concern in the Southeast Asian region. With environmental changes, evolving consumption patterns, and the globalization of trade, new food safety challenges are created, which put forward higher requirements on food technologies, food safety regulations, and international cooperation.

Cell-Surface-Anchored DNA Sensors for Simultaneously Monitoring Extracellular Sodium and Potassium Levels.

The K+ and Na+ levels in cells have a synergistic effect on many biological processes (BPs); therefore, the simultaneous detection of them is important. Here, we propose a novel Y-shaped DNA sensor for simultaneous monitoring of Na+ and K+ in extracellular microenvironments. The designed sensor contributed to the selective response to the above two ions. In addition, it performed the imaging of the above two ions on the cell surface in a real-time, on-site manner, which would shed more light on the association of the Na+/K+ content with regulatory BPs. We believe that this new strategy will be a promising tool to investigate the synergy of Na+/K+ in regulating different BPs.

Capsule-like molecular imprinted polymer nanoparticles for targeted and chemophotothermal synergistic cancer therapy.

Selective cancer cell targeting, controlled drug release, easy construction and multiple therapeutic modalities are some of the desirable characteristics of drug delivery systems. We designed and built simple capsule-like molecular imprinted polymer (MIP)-based nanoparticles for targeted and chemo-photothermal synergistic cancer therapy. Using dopamine (DA) as functional monomer, cross-linking agent as well as photo-thermal agent, ZIF-8 (zeoliticimidazolate framework-8) as drug carrier, epitope of EGFR (epidermal growth factor receptor) as template molecules, molecular imprinted polymer (MIP) drug carrier was constructed. The ability of MIP layer to bind to EGFR epitope endowed the MD (DOX@MIP) particles to recognize EGFR-overexpressing cancer cells, while the pH-responsiveness and photothermal conversion ability of PDA (polydopamine) achieved chemo-photothermal synergistic effects upon NIR irradiation. Taken together, the MD nanoparticles integrated cancer cell targeting recognition, intelligent drug release, biocompatibility and chemo-photothermal effects, and is therefore a promising tool for targeted cancer therapy with minimal toxicity to normal cells, as well as tumor imaging.

A nanoprobe for ratiometric imaging of glutathione in living cells based on the use of a nanocomposite prepared from dual-emission carbon dots and manganese dioxide nanosheets.

A ratiometric fluorescence assay for glutathione (GSH) was developed. The novel assay is based on a nanoprobe composed of manganese dioxide nanosheets (MnO2 NS) and dual-emission carbon dots (de-CDs) with intrinsic GSH-response property. After construction of the nanoprobe, two emission peaks of de-CDs were suppressed to varying degrees by MnO2 NS. The suppression was relieved and the two emission peaks recovered proportionally when MnO2 NS was decomposed by GSH, thus realizing the ratiometric assay for micromolar GSH. The intrinsic responsiveness of de-CDs to millimolar GSH broadens the analytical range of the nanoprobe. An appropriate precursor, calcon-carboxylic acid, was screened out to synthesize de-CDs via one-step hydrothermal treatment. The de-CD@MnO2 NS nanoprobe can measure GSH concentrations through the fluorescence intensity ratio between 435 and 516 nm excited at 365 nm. The range of response was from 1 µM to 10 mM and the detection limit reached 0.6 µM (3σ criterion). Benefiting from its good biocompatibility, the proposed nanoprobe has excellent applicability for intracellular GSH imaging.Graphical abstract Schematic representation of glutathione (GSH) ratiometric detection. The nanoprobe is prepared from dual-emission carbon dots (de-CDs) and manganese dioxide nanosheets (MnO2 NS). GSH removes quenching effect by decomposing MnO2 NS and induces intrinsic response of de-CDs, which realizes ratiometric detection.

Micelles via self-assembly of amphiphilic beta-cyclodextrin block copolymers as drug carrier for cancer therapy.

We developed intelligent, star-shaped amphiphilic ß-cyclodextrin (ß-CD) co-polymer nanocarriers to circumvent the poor drug loading and water-solubility of ß-CD. The secondary hydroxyl groups of ß-CD were methylated to improve solubility, and the primary hydroxyl groups were conjugated with mPEG-b-PCL-SH through disulfide linkage to amplify the hydrophobic cavity and enhance the stability of the nanocarrier. A series of amphiphilic ß-CD block copolymers (CCPPs) differing in molecular weights were synthesized that could self-assemble into core-shell nanospheres measuring 50-70 nm in water. The different CCPP carriers were screened for their drug loading, encapsulation and release efficiencies, and CCPP-2 showed the highest drug loading capacity of 31.9% by weight. These nanocarriers accumulated at the tumor site through the EPR effect and released the drug in a controlled manner in the reductive tumor microenvironment, with negligible premature leakage and side effects. Therefore, CCPP-2 shows significant potential as a smart and efficient nanovehicle for anticancer drug delivery.

Amphipathic ß-cyclodextrin nanocarriers serve as intelligent delivery platform for anticancer drug.

A novel glutathione-responsive (GSH-responsive) star-like amphiphilic polymer (C12H25)14-ß-CD-(S-S-mPEG)7 (denoted as CCSP) was designed for efficient antitumor drug delivery. The amphiphilic ß-cyclodextrin (ß-CD) self-polymerize in water to form a sphere with a diameter of 40-50 nm. The secondary hydroxyl groups of ß-CD were modified by dodecyl to form a hydrophobic core and the primary hydroxyl groups of ß-CD were decorated with PEG through disulfide bond to form a hydrophilic shell. Since the hydrophobic cavity of ß-CD was maintained, the hydrophobic core formed by dodecyl as well as cavity of ß-CD provided CCSP with a loading content as high as 39.6 wt%. Importantly, DOX@CCSP exhibited low drug leakage and negligible cytotoxicity in non-reductive physiological environment, while it showed rapid release and high cytotoxicity in reductive tumorous environment via the breakage of disulfide bond. In view of the above-mentioned advantages of DOX@CCSP nanocarriers such as high loading content, proper size, favorable stimulus-response release performance and low leakage, it is believed that CCSP may offer great potential to be used as an intelligent nanocarrier for anticancer drug delivery.