Copper-doped bismuth oxychloride nanosheets assembled into sphere-like morphology for improved photocatalytic inactivation of drug-resistant bacteria

Cu nano-armor supported on Ti Metal-Organic Frameworks: A stable catalyst for enhanced photocatalytic water disinfection

The rapid spread of microbial contamination and drug-resistant bacteria poses a significant threat to ecosystems and public health, highlighting the urgent need for efficient and stable disinfection materials. Metal-organic frameworks (MOFs) have emerged as promising functional materials for a variety of applications due to their regular microstructure and excellent physicochemical properties. However, their long-term use is limited by intrinsic instability. In this study, we designed copper nanolayers as protective armor for titanium-based MOFs (Cu/Ti-MOFs) to enhance their catalytic performance in photocatalytic disinfection under visible-light irradiation. The results demonstrated that Cu/Ti-MOFs exhibited slightly improved antimicrobial activity against Escherichia coli (E. coli), Staphylococcus aureus, and tetracycline-resistant E. coli compared to Ti-MOFs. More importantly, Cu/Ti-MOFs retained 92 % of their initial activity after seven consecutive catalytic cycles, whereas Ti-MOFs completely lost their photosensitive properties, indicating much higher catalytic stability of Cu/Ti-MOFs. This improvement was confirmed through various physicochemical characterizations and was attributed to the protection of active sites, catalyst reinforcement, and efficient surface reconstruction due to the introduction of the Cu nanolayer. This study provides a strategy for enhancing the long-term performance of MOF materials in photocatalytic water disinfection applications.

A novel Cu2+-coordinated fluorescent sensing system for specific detection of glyphosate and its applications in environmental and biological systems

Glyphosate is a non-selective herbicide widely used in agriculture, and its overexposure poses significant health and environmental risks. Herein, a novel Cu2+-coordinated fluorescent sensing system (HYBC-Cu2+ system) based on acylhydrazone groups was designed, capable of glyphosate-specific recognition. The HYBC-Cu2+ system was constructed with simple steps, with the advantages of short recognition time (< 1 min), good specificity, anti-interference, and excellent sensitivity (LOD = 95 nM). The effect of proton functional group on glyphosate resulted in Cu2+ of the HYBC-Cu2+ system being able to be competed down by the glyphosate to release HYBC thus inducing the fluorescence enhancement of the system and realizing the rapid detection of glyphosate. The recognition mechanism by the HYBC-Cu2+ system was verified by high-resolution mass spectrometry (HRMS), density function theory (DFT) calculations and Job's Plot. The system can cycle alternately to detect the glyphosate more than 6 times and effectively quantify trace glyphosate in environmental samples. Furthermore, the HYBC-Cu2+ system has low cytotoxicity and good membrane permeability, which can enter HeLa cells and zebrafish to react rapidly with exogenous glyphosate, resulting in fluorescence enhancements that are visually distinctive. The application of HYBC-Cu2+ system can further promote the development of pesticide residue monitoring methods such as glyphosate and provide scientific basis for policy making and public health protection.

Charge Engineering of Star-Shaped Organic Photosensitizers Enables Efficient Type-I Radicals for Photodynamic Therapy of Multidrug-Resistant Bacterial Infection

Infection induced by multidrug-resistant bacteria is now the second most common cause of accidental death worldwide. However, identifying a high-performance strategy with good efficiency and low toxicity is still urgently needed. Antibacterial photodynamic therapy (PDT) is considered a non-invasive and efficient approach with minimal drug resistance. Whereas, the precise molecular design for highly efficient oxygen-independent type-I photosensitizers is still undefined. In this work, the regulation of the positive charge of star-shaped NIR-emissive organic photosensitizers can boost radical generation for the efficient treatment of wounds infected with multidrug-resistant bacteria. With positive charge engineering, TPAT-DNN, which has six positive charges, mainly produces hydroxyl radicals via the type-I pathway, while TPAT-DN, which has three positive charges, tends to generate singlet oxygen and superoxide radicals. For multidrug-resistant bacteria, TPAT-DNN exhibited specific killing effects on multidrug-resistant gram-positive bacteria at low concentrations, while TPAT-DN is similar antibacterial effects on both multidrug-resistant gram-negative and gram-positive bacteria. Furthermore, the efficiency and safety of TPAT-DNN for eradicating multidrug-resistant bacteria methicillin-resistant S. aureus (MRSA) infection and accelerating wound healing in an MRSA-infected mouse model are demonstrated. This work offers a new approach toward manipulating efficient type-I photosensitizers for MRSA treatment.

Tailored Phototherapy Agent by Infection Site In Situ Activated Against Methicillin-Resistant S. aureus

Phototherapy, including photodynamic therapy (PDT) and photothermal therapy (PTT), is a promising treatment approach for multidrug resistant infections. PDT/PTT combination therapy can more efficiently eliminate pathogens without drug resistance. The key to improve the efficacy of photochemotherapy is the utilization efficiency of non-radiation energy of phototherapy agents. Herein, a facile phototherapy molecule (SCy-Le) with the enhancement of non-radiative energy transfer is designed by an acid stimulation under a single laser. Introduction of the protonated receptor into SCy-Le results in a distorted intramolecular charge in the infected acidic microenvironment, pH ≈ 5.5, which in turn, enhances light capture, reduces the singlet-triplet transition energies (ΔES1-T1), promotes electron system crossing, enhances capacity of reactive oxygen species generation, and causes a significant increase in temperature by improving vibrational relaxation. SCy-Le shows more than 99% bacterial killing rate against both methicillin-resistant Staphylococcus aureus and its biofilms in vitro and causes bacteria-induced wound healing in mice. This work will provide a new perspective for the design of phototherapy agents, and the emerging photochemotherapy will be a promising approach to combat the problem of antibiotic resistance.

3D/2D-Bismuth Oxybromide Spheres with Selenium-Doped Graphitic Carbon Nitride Sheets: An Efficient Electrocatalyst for the Detection of Arsenic Drug Roxarsone

Heavy metals are crucial carcinogenic agents threatening the environment and living habituates. Among them, arsenic (As) is an important metalloid that is categorized as a group I toxic carcinogen. Roxarsone (RX) is an organoarsenic antibiotic compound primarily used as a veterinarian drug and growth promoter for poultry animals. The extensive usage of RX increased the accumulation of As in living beings and the ecosystem. Therefore, we have prepared an electrochemical sensor based on 3D bismuth oxybromide with 2D selenium-doped graphitic carbon nitride (BOB/SCN) electrocatalyst for the rapid detection of RX. The elemental and structural details were thoroughly investigated with several spectroscopic techniques. The electrochemical properties were measured by impedance and voltammetric measurements. The electrocatalytic behavior toward the RX was estimated with different voltammetric methods. Therefore, our BOB/SCN-based electrochemical sensor demonstrated a low detection limit (2.3 nM), low quantification value (7.7 nM), optimal sensitivity (0.675 μA μM-1 cm-2), and good linear ranges (0.01-77 and 77-857 μM). Additionally, this sensor showed good electrochemical performance and was applied to monitor the RX in various real samples with remarkable recoveries. Based on these results, our BOB/SCN sensor is a promising electrochemical platform for determining RX.

Biocompatible plasma-treated liquids: A sustainable approach for decontaminating gastrointestinal-infection causing pathogens

Nosocomial infections are a serious threat and difficult to cure due to rising antibiotic resistance in pathogens and biofilms. Direct exposure to cold atmospheric plasma (CAP) has been widely employed in numerous biological research endeavors. Nonetheless, plasma-treated liquids (PTLs) formulated with physiological solutions may offer additional benefits such as enhanced portability, and biocompatibility. Additionally, CAP-infused long-lived reactive oxygen and nitrogen species (RONS) such as nitrite (NO2-), nitrate (NO3-), and hydrogen peroxide (H2O2) can synergistically induce their antibacterial activity. Herein, we investigated those argon-plasma jet-treated liquids, including Ringer's lactate (RL), phosphate-buffered saline (PBS), and physiological saline, have significant antibacterial activity against nosocomial/gastrointestinal-causing pathogens, which might be due to ROS-mediated lipid peroxidation. Combining the conventional culture-based method with propidium iodide monoazide quantitative PCR (PMAxx™-qPCR) indicated that PTLs induce a minimal viable but non-culturable (VBNC) state and moderately affect culturable counts. Specifically, the PTL exposure resulted in pathogenicity dysfunction via controlling T3SS-related effector genes of S. enterica. Overall, this study provides insights into the effectiveness of PTLs for inducing ROS-mediated damage, controlling the virulence of diarrheagenic bacteria, and modulating homeostatic genes.

Accelerated Wound Healing by Electrospun Multifunctional Fibers with Self-Powered Performance

Wound healing has been a persistent clinical challenge for a long time. Electrical stimulation is an effective therapy with the potential to accelerate wound healing. In this work, the self-powered electrospun nanofiber membranes (triples) were constructed as multifunctional wound dressings with electrical stimulation and biochemical capabilities. Triple was composed of a hydrolyzable inner layer with antiseptic and hemostatic chitosan, a hydrophilic core layer loaded with conductive AgNWs, and a hydrophobic outer layer fabricated by self-powered PVDF. Triple exhibited presentable wettability and acceptable moisture permeability. Electrical performance tests indicated that triple can transmit electrical signals formed by the piezoelectric effect to the wound. High antibacterial activities were observed for triple against Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa, with inhibition rates of 96.52, 98.63, and 97.26%, respectively. In vitro cell assays demonstrated that triple cells showed satisfactory proliferation and mobility. A whole blood clotting test showed that triple can enhance hemostasis. The innovative self-powered multifunctional fibers presented in this work offer a promising approach to addressing complications and expediting the promotion of chronic wound healing.