Methylene Blue-Fortified Molybdenum Trioxide Nanoparticles: Harnessing Radical Scavenging Property

Rapidly responsive and highly selective NIR fluorescent probe for detecting hydrogen sulfide in food samples and living cells

Hydrogen sulfide (H2S) is a pungent gas that is one of the key mediators of signal transduction in biological systems, and its presence is related to the freshness of some protein foods. Using phenothiazine derivatives as fluorophores and 2, 4-dinitrobenzene sulfonate (DNBS) fragments as reaction groups, a near-infrared (NIR) probe WX-HS for H2S identification was designed. With the addition of H2S, WX-HS appeared a strong fluorescence signal at 660 nm with short reaction time (90 s) and high sensitivity, and fluorescence state change from non-fluorescent to orange-red. In addition, WX-HS could effectively detect H2S produced during food oxidation. Based on its low cytotoxicity, the WX-HS probe further enabled the detection and imaging of H2S in A549 cells.

A Novel NIR Fluorescent Probe for Rapid Response to Hydrogen Sulfide

Hydrogen sulfide (H2S), as an important small molecule bioregulator, plays a key role in many physiological activities and signaling, and abnormal fluctuations in H2S concentration can lead to a variety of diseases. Therefore, it is of great significance to develop a near-infrared fluorescence probe to visualize fluctuations in H2S levels. This work is based on Sulfur-substituted dicyanomethylene-4 H-chromene (DCM), A novel NIR fluorescent probe (E) -3 - (2 - (4 - (dicyanomethylene) -6-methyl-4 H-Thiochromen-2-yl)vinyl-1-methylquinolin-1-ium (DMT) was synthesized successfully. Research has found that in weakly alkaline environments, the probe DMT reacts rapidly with H2S (only 10 s), the fluorescence intensity at 684 nm is enhanced by about 60 fold, the detection limit is as low as 0.1623 µM, the Stokes shift is large (94 nm), and strong selectivity as well as anti-interference ability towards H2S. This will provide a new method for the rapid detection and further application of H2S.

Single Side-Chain-Modulatory of Hemicyanine for Optimized Fluorescence and Photoacoustic Dual-Modality Imaging of H2S In Vivo

Near-infrared fluorescence (NIRF)/photoacoustic (PA) dual-modality imaging integrated high-sensitivity fluorescence imaging with deep-penetration PA imaging has been recognized as a reliable tool for disease detection and diagnosis. However, it remains an immense challenge for a molecule probe to achieve the optimal NIRF and PA imaging by adjusting the energy allocation between radiative transition and nonradiative transition. Herein, a simple but effective strategy is reported to engineer a NIRF/PA dual-modality probe (Cl-HDN3) based on the near-infrared hemicyanine scaffold to optimize the energy allocation between radiative and nonradiative transition. Upon activation by H2S, the Cl-HDN3 shows a 3.6-fold enhancement in the PA signal and a 4.3-fold enhancement in the fluorescence signal. To achieve the sensitive and selective detection of H2S in vivo, the Cl-HDN3 is encapsulated within an amphiphilic lipid (DSPE-PEG2000) to form the Cl-HDN3-LP, which can successfully map the changes of H2S in a tumor-bearing mouse model with the NIRF/PA dual-modality imaging. This work presents a promising strategy for optimizing fluorescence and PA effects in a molecule probe, which may be extended to the NIRF/PA dual-modality imaging of other disease-relevant biomarkers.

Green Synthesis of Molybdenum Nanoparticles From Solanum xanthocarpum and Evaluation of Their Antimicrobial and Antioxidant Activity Against Multidrug-Resistant Wound Isolates

INTRODUCTION

In recent years, antimicrobial drug resistance has emerged as a serious global public health concern, according to the World Health Organization data. The emergence of pathogens resistant to multiple drugs has been linked to an increase in morbidity and mortality from microbial infections. The study's main goal is to explore the efficacy of using Solanum xanthocarpum in the green synthesis of molybdenum nanoparticles (Mo NPs) for antibacterial and antioxidant properties.

METHODS

An eco-friendly method of synthesizing Mo NPs was accomplished using an aqueous extract of Solanum xanthocarpum. Characterization of the synthesized nanoparticles was done by UV-visible spectroscopy (UV-Vis), Fourier-transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscope (SEM), and energy-dispersive X-ray spectroscopy (EDX). After that, antibacterial and antioxidant activity was further evaluated.

RESULTS

The UV-visible spectrophotometer analysis confirmed the presence of synthesized Mo NPs showing a peak around 320 nm. The presence of functional compounds like C-CI, C-H, C=C, and O=C=O was confirmed by FT-IR spectrum analysis. The positions of diffraction peaks in Mo NP patterns were identified using XRD analysis; they were more crystalline (82.7%) and less amorphous (17.3%). The presence of the elements molybdenum (Mo), carbon (C), and oxygen (O) was confirmed by the EDX spectrum and irregular shapes shown in the SEM images. Further, the antimicrobial study results showed the formation of an inhibition zone against 27 mm for Klebsiella pneumoniae, 24 mm for Pseudomonas aeruginosa, 22 mm for Staphylococcus aureus, and 24 mm for Enterococcus faecalis, respectively, at a high concentration 80 μg/ml of Mo NPs. The maximum antioxidant activity at 100 μg/ml was 73.49%, compared to the standard ascorbic acid (74.25%). Additionally, the moderate activity at 60 μg/ml was 53.21%, compared to the standard (56.5%), and the minimal activity at 20 μg/ml was 30.21%, compared to the standard (36.89%).

CONCLUSION

The environmentally friendly synthesized Mo NPs from Solanum xanthocarpum exhibited antioxidant activity. Furthermore, the findings show that Mo NPs mediated by Solanum xanthocarpum can inhibit antibiotic-resistant bacteria, especially methicillin-resistant Staphylococcus aureus, Klebsiella pneumoniae, Pseudomonas aeruginosa, and Enterococcus faecalis. In order to understand further how nanoparticles work against bacteria that are resistant to many drugs, additional research and clinical studies would be needed.

Tadpole-Like Anisotropic Polymer/Lipid Janus Nanoparticles for Nose-to-Brain Drug Delivery: Importance of Geometry, Elasticity on Mucus-Penetration Ability

Asymmetric geometry (aspect ratio >1), moderate stiffness (i.e., semielasticity), large surface area, and low mucoadhesion of nanoparticles are the main features to reach the brain by penetrating across the nasal mucosa. Herein, a new application has been presented for the use of multifunctional Janus nanoparticles (JNPs) with controllable geometry and size as a nose-to-brain (N2B) delivery system by changing proportions of Precirol ATO 5 and polycaprolactone compartments and other operating conditions. To bring to light the N2B application of JNPs, the results are presented in comparison with polymer and solid lipid nanoparticles, which are frequently used in the literature regarding their biopharmaceutical aspects: mucoadhesion and permeability through the nasal mucosa. The morphology and geometry of JPs were observed via cryogenic-temperature transmission electron microscopy images, and their particle sizes were verified by dynamic light scattering, atomic force microscopy, and scanning electron microscopy. Although all NPs showed penetration across the mucus barrier, the best increase in penetration was observed with asymmetric and semielastic JNPs, which have low interaction ability with the mucus layer. This study presents a new and promising field of application for a multifunctional system suitable for N2B delivery, potentially benefiting the treatment of brain tumors and other central nervous system diseases.

A NIR ratiometric fluorescent probe for the rapid detection of hydrogen sulfide in living cells and zebrafish

Hydrogen sulfide (H2S) acts as a gas transporter and cell protector and plays a role in a number of disorders and signaling processes. Given that the half-life of H2S in biological systems is between seconds and minutes, the development of rapid and accurate technologies for reliable monitoring H2S levels and dynamics in organisms is critical. However, it is still difficult to design innovative near-infrared fluorescent probes that can quickly and accurately detect H2S. Here, we constructed a novel NIR ratiometric fluorescent probe based on the "aldehyde group auxiliary strategy", Cy-H2S, for the quantitative detection and precise imaging of H2S in living cells and zebrafish. Cy-H2S responded quickly (150 s) and was highly sensitive (0.179 μM) to H2S donor. Cy-H2S was further successfully employed to track endogenous H2S fluctuation in HCT116 cells and zebrafish and evaluated the release efficiency of the H2S prodrug in a NIR ratiometric imaging way. Cy-H2S has the potential to be used as a reliable indication of H2S levels in living cells and zebrafish, as well as an innovative and practical instrument for furthering the physiological research of H2S, which will encourage the creation of advanced NIR ratiometric probes for a variety of biological applications.

Review on Methylene Blue: Its Properties, Uses, Toxicity and Photodegradation

The unavailability of clean drinking water is one of the significant health issues in modern times. Industrial dyes are one of the dominant chemicals that make water unfit for drinking. Among these dyes, methylene blue (MB) is toxic, carcinogenic, and non-biodegradable and can cause a severe threat to human health and environmental safety. It is usually released in natural water sources, which becomes a health threat to human beings and living organisms. Hence, there is a need to develop an environmentally friendly, efficient technology for removing MB from wastewater. Photodegradation is an advanced oxidation process widely used for MB removal. It has the advantages of complete mineralization of dye into simple and nontoxic species with the potential to decrease the processing cost. This review provides a tutorial basis for the readers working in the dye degradation research area. We not only covered the basic principles of the process but also provided a wide range of previously published work on advanced photocatalytic systems (single-component and multi-component photocatalysts). Our study has focused on critical parameters that can affect the photodegradation rate of MB, such as photocatalyst type and loading, irradiation reaction time, pH of reaction media, initial concentration of dye, radical scavengers and oxidising agents. The photodegradation mechanism, reaction pathways, intermediate products, and final products of MB are also summarized. An overview of the future perspectives to utilize MB at an industrial scale is also provided. This paper identifies strategies for the development of effective MB photodegradation systems.

Heterostructured TiO2@HKUST-1 for the enhanced removal of methylene blue by integrated adsorption and photocatalytic degradation

Aiming at exploring an effective photocatalytic adsorbent for organic dye removal, a series of heterostructured TiO₂@HKUST-1 photocatalysts, by incorporating HKUST-1 with different TiO₂ nanoparticles loading, were prepared by single-step hydrothermal method. The morphology and surface characteristics of the as-prepared TiO₂@HKUST-1were analyzed using SEM, HRTEM, XRD, FTIR, UV-vis DRS, and Photoluminescence techniques. The adsorption-photocatalytic degradation of the model dye methylene blue (MB) on the catalysts was investigated. It was indicated that the introduction of a certain amount of TiO₂ on the surface of HKUST-1 could improve the transfer and separation of the photogenerated charge carriers, resulting in the enhanced photocatalytic activity. The optimal 0.02TiO₂@HKUST-1 exhibited the highest MB removal rate with about 4.4 and 19.3 times as high MB removal efficiency as that of HKUST-1 and TiO₂, respectively. Heterostructured TiO₂@HKUST-1 materials for the removal of MB involved the integrated adsorption and visible light photocatalysis. Meanwhile, the composite exhibited good reusability in the process of cyclic experiments. Therefore, this work provides a potential MOF-based photocatalytic adsorbent for organic dye removal.

Survival upon Staphylococcus aureus mediated wound infection in Caenorhabditis elegans and the mechanism entailed

Infection following injury is one of the major threats which causes huge economic burden in wound care management all over the world. Injury often results with poor healing when coupled by following infection. In contrast to this, we observed enhanced survival of wound infected worms compared to wounded worms in Caenorhabditis elegans wound model while infecting with Staphylococcus aureus. Hence, the study was intended to identify the mechanism for the enhanced survival of wound infected worms through LCMS/MS based high throughput proteomic analysis. Bioinformatics analyses of the identified protein players indicated differential enrichment of several pathways including MAPK signaling, oxidative phosphorylation and phosphatidylinositol signaling. Inhibition of oxidative phosphorylation and phosphatidylinositol signaling through chemical treatment showed complete reversal of the enhanced survival during wound infection nevertheless mutant of MAPK pathway did not reverse the same. Consequently, it was delineated that oxidative phosphorylation and phosphatidylinositol signaling are crucial for the survival. In this regard, elevated calcium signals and ROS including O^- and H₂O₂ were observed in wounded and wound infected worms. Consequently, it was insinuated that presence of pathogen stress could have incited survival in wound infected worms with the aid of elevated ROS and calcium signals.

Injectable self-healing bioactive antioxidative one-component poly(salicylic acid) hydrogel with strong ultraviolet-shielding for preventing skin light injury

The design and development of one-component temperature-sensitive bioactive hydrogel with multifunctional properties for protecting skin against light injury remain a challenge. Herein, we report a bioactive multifunctional poly(salicylic acid)-F127-poly(salicylic acid) copolymer hydrogel (FPSa) with one-component for potential skin protection applications. The FPSa hydrogel possesses the thermosensitivity (23 °C), injectability, self-healing ability, ultraviolet shielding (shielding the wavelength between 280 and 370 nm), and antioxidation activity (above 70%), and also showed the good cytocompatibility (cell survival rate >90% and hemolysis rate less than 5%) and biodegradability (90% weight loss at 3 days). The in vivo animal model showed that FPSa hydrogel could effectively protect the skin tissue and prevent the ultraviolet induced injury. This study can provide a strategy to design multifunctional bioactive hydrogel with simple composition for disease therapy and regenerative medicine.

Catalytic Nanozyme for Radiation Protection

Radiotherapy has been widely used in clinical cancer treatment. However, the ionizing radiation required to kill the tumor will inevitably cause damage to the surrounding normal tissues. To minimize the radiation damage and side effects, small molecular radioprotective agents have been used as clinical adjuvants for radiation protection of healthy tissues. However, the shortcomings of small molecules such as short circulation time and rapid kidney clearance from the body greatly hinder their biomedical applications. In recent years, nanozymes have attracted much attention because of their potential to treat a variety of diseases. Nanozymes exhibit catalytic properties and antioxidant capabilities to provide a potential solution for the development of high-efficiency radioprotective agents in radiotherapy and nuclear radiation accidents. Therefore, in this review, we systematically summarize the catalytic nanozymes used for radiation protection of healthy tissues and discuss the challenges and future prospects of nanomaterials in the field of radiation protection.

Glioma cells eradication by photoexcitation of bioengineered molybdenum trioxide nanoparticles synthesized by wet chemical and microwave route: Dose dependent photosensitizer bioactivity

Here, we surveyed the usage of MoO₃ nanostructure in role of a photosensitizer to eradicate glioma cells. This is the first endeavor upon survey of usage of nanostructured MoO₃ to treat glioma in vitro. Here, we offer a simple way for preparation of bioactive MoO₃ nanostructure via two different routes; wet chemical and microwave. The influence of diverse experimental factors like various alcoholic solvents and presence of capping agent was investigated on the final properties of synthesized products. Dimension and morphology of inorganic molybdenum trioxide nanostructures checked with TEM, HRTEM and also SEM images. Moreover, the cytotoxicity effect of optimized MoO₃ nanoparticles was investigated on T98 and A172 cell lines. Both T98 and A172 cell lines indicated dose-dependent manner in the presence of increasing concentration of MoO₃ nanostructures, but T98 cells were less sensitive to MoO₃ in comparison with A172. Anti-glioma role of MoO₃ nanostructures excited with the aid of UVC illumination studied in vitro as well. By studying the UV exposure lonely, it is evident that UV effects on cell viability about 50% in both cell lines after 24 h. Interestingly, by combining nanostructured MoO₃ with UVC illumination, decrement in the proliferation value could be remarkably occurred in comparison with controls. The outcomes denote that the photodynamic therapy with the help of nanostructured MoO₃ may be beneficial to treat glioma.

State-of-Art Bio-Assay Systems and Electrochemical Approaches for Nanotoxicity Assessment

Innovations in the field of nanotechnology, material science and engineering has rendered fruitful utilities in energy, environment and healthcare. Particularly, emergence of surface engineered nanomaterials offered novel varieties in the daily consumables and healthcare products including therapeutics and diagnostics. However, the nanotoxicity and bioactivity of the nanomaterials upon interaction with biological system has raised critical concerns to individual as well as to the environment. Several biological models including plant and animal sources have been identified to study the toxicity of novel nanomaterials, correlating the physio-chemical properties. Biological interaction of nanomaterials and its mediated physiological functions are studied using conventional cell/molecular biological assays to understand the expression levels of genetic information specific to intra/extra cellular enzymes, cell viability, proliferation and function. However, modern research still demands advanced bioassay methods to screen the acute and chronic effects of nanomaterials at the real-time. In this regard, bioelectrochemical techniques, with the recent advancements in the microelectronics, proved to be capable of providing non-invasive measurement of the nanotoxicity effects (in vivo and in vitro) both at single cellular and multicellular levels. This review attempted to provide a detailed information on the recent advancements made in development of bioassay models and systems for assessing the nanotoxicology. With a short background information on engineered nanomaterials and physiochemical properties specific to consumer application, present review highlights the multiple bioassay models evolved for toxicological studies. Emphasize on multiple mechanisms involved in the cell toxicity and electrochemical probing of the biological interactions, revealing the cytotoxicity were also provided. Limitations in the existing electrochemical techniques and opportunities for the future research focusing the advancement in single molecular and whole cell bioassay has been discussed.

Carbohydrate coated fluorescent mesoporous silica particles for bacterial imaging

This work investigated the synthesis of carbohydrate functionalized methylene blue doped amine grafted mesoporous silica nanoparticles (MB AMSN) and their application in bioimaging. A single-pot synthesis methodology was developed via a modified co-condensation sol-gel technique for simultaneous incorporation of the dye molecule in the nanoparticles, with amine grafting for subsequent functionalization. The obtained nanoparticles (∼ 450 nm) are mesoporous and have a high surface area (538 m²/g), pore-volume (0.3 cm³/g), showed excellent UV-vis absorbance, and dye encapsulation efficiency (> 75 %). These fluorescent nanoparticles were further functionalized with carbohydrate molecules before application as contrast agents in bacterial cells. In the present study, gram-positive (E. coli) and gram-negative (B. subtilis) bacteria were used as model organisms. Confocal laser microscopy results showed that the nanoparticles are highly fluorescent, and SEM of glucose conjugated MB doped nanoparticles indicated close interaction with E. coli with no toxicity observed towards either bacterial cells. The results demonstrate that by suitable surface functionalization, the methylene blue doped silica nanoparticles can be used as bioimaging agents.

The controllable growth of ultrathin MnO2 on polydopamine nanospheres as a single nanoplatform for the MRI-guided synergistic therapy of tumors

The integration of two-dimensional (2D) nanosheets with biocompatible photothermal nanoparticles may produce effective multifunctional nanotheranostic agents.