Reversible Chemosensor for Bioimaging and Biosensing of Zn(II) and hpH in Cells, Larval Zebrafish, and Plants with Dual-Channel Fluorescence Signals.

Zinc/Zn(II) is an essential trace element for humans and acts as an important substance that maintains the normal growth, development, and metabolism of the body. Excess or deficient Zn(II) can cause abnormal metabolism in the human body, leading to a series of diseases. Moreover, biosystems have complex homeostasis systems, especially harsh pH (OH-) environments. Thus, investigating the variation in the levels of Zn(II) and OH- is extremely important in clinical, medical, and environmental testing. Nevertheless, the lack of practical and convenient fluorescence imaging tools limits the tracing of Zn(II) and OH- in biosystems. In this work, a well-designed dual-channel fluorescent signal response chemosensor (DACH-fhba) was assembled for selective sensing of Zn(II) and OH- in the biosystem using a fluorescence turn-on strategy. On encountering Zn(II), the chemosensor emitted a blue fluorescence signal (455 nm). Meanwhile, the bright green fluorescence signal (530 nm) increased with OH- addition simultaneously. With the blue/green dual fluorescence response of DACH-fhba, the sensor exhibited high stability and reversibility. Notably, the bioimaging revealed that DACH-fhba successfully tracked Zn(II) and OH- in live cells, larval zebrafish, and plants. Further results implied that DACH-fhba can be used to achieve visual detection of Zn(II) and OH- in organisms. Altogether, this work is conducive to the monitoring of Zn(II) and OH- in organisms and promotes the understanding of the function of Zn(II) and OH- in biosystems.

The CuO and AgO co-modified ZnO nanocomposites for promoting wound healing in Staphylococcus aureus infection.

Bacterial has become a common pathogen of humans owing to their drug-resistant effects and evasion of the host immune system, with their ability to form biofilm and induce severe infections, a condition which has become a primary public health concern globally. Herein, we report on CuO@AgO/ZnO NPs antibacterial activity enhanced by near-infrared (NIR) light which was effective in the elimination of Staphylococcus aureus and the Pseudomonas aeruginosa. The CuO@AgO/ZnO NPs under NIR significantly eradicated S. aureus and its biofilm and P. aeruginosa in vitro, and subsequently exhibited such phenomenon in vivo, eliminating bacteria and healing wound. This demonstrated the combined intrinsic antibacterial potency of the Cu and Ag components of the CuO@AgO/ZnO NPs was enhanced tremendously to achieve such outcomes in vitro and in vivo. Considering the above advantages and facile preparation methods, the CuO@AgO/ZnO NPs synthesized in this work may prove as an important antibacterial agent in bacterial-related infection therapeutics and for biomedical-related purposes.

A Vehicle-Free Antimicrobial Polymer Hybrid Gold Nanoparticle as Synergistically Therapeutic Platforms for Staphylococcus aureus Infected Wound Healing.

Pathogenic bacteria infection is a serious threat to human public health due to the high morbidity and mortality rates. Nano delivery system for delivering antibiotics provides an alternative option to improve the efficiency compared to conventional therapeutic agents. In addition to the drug loading capacity of nanocarriers, which is typically around 10%, further lowers the drug dose that pathological bacteria are exposed to. Moreover, nanocarriers that are not eliminated from the body may cause side effects. These limitations have motivated the development of self-delivery systems that are formed by the self-assembly of different therapeutic agents. In this study, a vehicle-free antimicrobial polymer polyhexamethylene biguanide (PHMB, with bactericidal and anti-biofilm functions) hybrid gold nanoparticle (Au NPs, with photothermal therapy (PTT)) platform (PHMB@Au NPs) is developed. This platform exhibits an excellent synergistic effect to enhance the photothermal bactericidal effect for Staphylococcus aureus under near-infrared irradiation. Furthermore, the results showed that PHMB@Au NPs inhibit the formation of biofilms, quickly remove bacteria to promote wound healing through PTT in infection model in vivo, and even mediate the transition of macrophages from M1 to M2 type, and accelerate tissue angiogenesis. PHMB@Au NPs will have promising value as highly effective antimicrobial agents for patient management.

Reaction-based chemosensor as dual-channel indicator for visualizing and bioimaging of exogenous hypochlorite concentrations in living cells, Pseudomonas aeruginosa, and zebrafish.

Tracking and quantifying hypochlorite (ClO-) in biological systems and environments remain challenging tasks, and many efforts have been made to improve ClO- recognition performance by modifying the sensor structure. In this study, a pre-designed coumarin/furanohydrazide-based sensor (CMFH) with the coumarin moiety as the building block (fluorogen) was rationally prepared as a ratiometric and colorimetric chemosensor for ClO- recognition. As expected, CMFH demonstrated excellent sensitivity and selectivity for ClO- detection. The fluorescence signal ratio (F466/F556) showed strong ClO- dependency, and the sensor exhibited ultrafast detection (within 60 s) and a low detection limit of 563 nM. Due to its low cytotoxicity and good tissue permeability, CMFH was demonstrated as a dual-channel sensor for ClO- bioimaging and visualization in cells, zebrafish, and even bacteria. Furthermore, CMFH-loaded paper strips were successfully applied to the colorimetric and fluorescent visualization of ClO-. The results demonstrate that CMFH has potential application value for tracking ClO- in various biosystems and environments.

Mitochondria-Targeted Chemosensor to Discriminately and Continuously Visualize HClO and H2S with Multiresponse Fluorescence Signals for In Vitro and In Vivo Bioimaging.

Bioactive molecules play a vital role in the process of regulating the redox balance in the intracellular environment, especially in maintaining the function of organelles. To explore the association and function of bioactive molecules in organelles, it is essential to develop a chemosensor tool that uses multiresponse fluorescence signals to distinguish between and track two related bioactive molecules in organelles. However, the development of sensors with multiresponse functions is still a challenging task. Herein, we present a unique and practical single chemosensor (Mito-CTC) that can monitor HClO (as an oxidative substance) and H2S (as a reductive substance) in mitochondria (organelle targeting) with multiresponse fluorescence signals. The response of the sensor to HClO and H2S changes from red to green and blue channel emission simultaneously, respectively, thereby providing a specific signal response to reductive/oxidative substances in the mitochondria. Using a single chemosensor, we have realized multichannel bioimaging of the exogenous and endogenous HClO and H2S in cellular mitochondria. Additionally, the excellent properties of the sensor Mito-CTC can be used to reveal the relationship between HClO and H2S in mitochondria. Meanwhile, Mito-CTC has been endowed with the ability to image in bacteria and zebrafish attributed to the good permeability and low cytotoxicity. Expectantly, drug-induced liver injury (DILI) caused by fluoxetine (an antidepressant drug) and the degree of drug-induced toxicity to the liver were evaluated using Mito-CTC through discriminating and imaging HClO, indicating that Mito-CTC has the potential function of evaluating the toxicity of the drug to the liver.