Effects of metal ions on the activity of protein tyrosine phosphatase VHR: highly potent and reversible oxidative inactivation by Cu2+ ion

Biomimetic gold nanocages incorporating copper-human serum albumin for tumor immunotherapy via cuproptosis-lactate regulation

Cancer immunotherapy remains a significant challenge due to insufficient proliferation of immune cells and the sturdy immunosuppressive tumor microenvironment. Herein, we proposed the hypothesis of cuproptosis-lactate regulation to provoke cuproptosis and enhance anti-tumor immunity. For this purpose, copper-human serum albumin nanocomplex loaded gold nanocages with bacterial membrane coating (BAu-CuNCs) were developed. The targeted delivery and disassembly of BAu-CuNCs in tumor cells initiated a cascade of reactions. Under near infrared (NIR) laser irradiation, the release of copper-human serum albumin (Cu-HSA) was enhanced that reacted with intratumoral glutathione (GSH) via a disulfide exchange reaction to liberate Cu2+ ions and exert cuproptosis. Subsequently, the cuproptosis effect triggered immunogenic cell death (ICD) in tumor by the release of damage associated molecular patterns (DAMPs) to realize anti-tumor immunity via robust production of cytotoxic T cells (CD8+) and helper T cells (CD4+). Meanwhile, under NIR irradiation, gold nanocages (AuNCs) promoted excessive reactive oxygen species (ROS) generation that played a primary role in inhibiting glycolysis, reducing the lactate and ATP level. The combine action of lower lactate level, ATP reduction and GSH depletion further sensitized the tumor cells to cuproptosis. Also, the lower lactate production led to the significant blockage of immunosuppressive T regulatory cells (Tregs) and boosted the anti-tumor immunity. Additionally, the effective inhibition of breast cancer metastasis to the lungs enhanced the anti-tumor therapeutic impact of BAu-CuNCs + NIR treatment. Hence, BAu-CuNCs + NIR concurrently induced cuproptosis, ICD and hindered lactate production, leading to the inhibition of tumor growth, remodeling of the immunosuppressive tumor microenvironment and suppression of lung metastasis. Therefore, leveraging cuproptosis-lactate regulation, this approach presents a novel strategy for enhanced tumor immunotherapy.

Characterization and Application of an Aspartate Dehydrogenase from Achromobacter denitrificans

A novel gene encoding aspartate dehydrogenase (ASPDH) has been discovered in Achromobacter denitrificans. The product of this gene has a strict dependence on NADH and demonstrated significant reductive activity towards not only oxaloacetate (OAA) but also 2-ketobutyric acid. Further enzymatic characterization revealed the kinetic parameters of ASPDH for OAA and 2-ketobutyric acid were as follows: Km values of 4.25 mM and 0.89 mM, Vmax values of 10.67 U mg-1 and 2.10 U mg-1, and Kcat values of 3.70 s-1 and 0.72 s-1, respectively. The enzyme also showed a dependency on metal ions, with EDTA and Cu2+ exerting strong inhibitory effects, while Ca2+ and Fe2+ exhibited pronounced enhancing effects. By utilizing a whole-cell biocatalyst system comprising glucose dehydrogenase (GDH) and ASPDH as a coupled system to replenish cofactors by oxidizing glucose, enabling the effective conversion of 2-ketobutyric acid to L-2-aminobutyric acid (L-2-ABA) with 97.2% yield.

A Multifunctional Scaffold for Bone Infection Treatment by Delivery of microRNA Therapeutics Combined With Antimicrobial Nanoparticles

Treating bone infections and ensuring bone repair is one of the greatest global challenges of modern orthopedics, made complex by antimicrobial resistance (AMR) risks due to long-term antibiotic treatment and debilitating large bone defects following infected tissue removal. An ideal multi-faceted solution would will eradicate bacterial infection without long-term antibiotic use, simultaneously stimulating osteogenesis and angiogenesis. Here, a multifunctional collagen-based scaffold that addresses these needs by leveraging the potential of antibiotic-free antimicrobial nanoparticles (copper-doped bioactive glass, CuBG) to combat infection without contributing to AMR in conjunction with microRNA-based gene therapy (utilizing an inhibitor of microRNA-138) to stimulate both osteogenesis and angiogenesis, is developed. CuBG scaffolds reduce the attachment of gram-positive bacteria by over 80%, showcasing antimicrobial functionality. The antagomiR-138 nanoparticles induce osteogenesis of human mesenchymal stem cells in vitro and heal a large load-bearing defect in a rat femur when delivered on the scaffold. Combining both promising technologies results in a multifunctional antagomiR-138-activated CuBG scaffold inducing hMSC-mediated osteogenesis and stimulating vasculogenesis in an in vivo chick chorioallantoic membrane model. Overall, this multifunctional scaffold catalyzes killing mechanisms in bacteria while inducing bone repair through osteogenic and angiogenic coupling, making this platform a promising multi-functional strategy for treating and repairing complex bone infections.

Specializing Carbon Nanozyme Active Sites for Sensitive Alkaline Phosphatase Activity Metal-Free Detection

As biological enzymes regulate metabolic processes, alkaline phosphatase (ALP) is a critical diagnostic indicator associated with many diseases. To accurately measure the enzyme activity, nanozymactic materials can offer sensitive strategies for ALP detection. However, nanozymes often lack specific target binding sites, and the presence of common co-components, e. g., metal ions, may cause false-positive or false-negative results in enzyme activity determination. Herein, we developed a colorimetric assay for ALP detection using metal-free nanozymatic carbon dots (CDs). The ALP hydrolysis of pyrophosphate ions (PPi) to phosphate ions (Pi) induces a "turn-on" response based on the nanozyme activity. This PPi-induced inhibition mechanism is extensively studied via the Michaelis-Menten model, revealing that PPi acts as a noncompetitive inhibitor for CDs at a binding site distinct from the common nanozyme active site. With superior responses to ALP substrates, a highly sensitive and selective method is established for sensing ALP activity with a linear range of 0.010-0.200 U/L and a detection limit of 0.009 U/L. This finding explores the recognition and binding behavior of nanozymes, allowing for precise and reliable measurements even in complex samples, and represents a significant breakthrough for nanozyme-based assays in biological analysis.

Development of antibacterial neural stimulation electrodes via hierarchical surface restructuring and atomic layer deposition

Miniaturization and electrochemical performance enhancement of electrodes and microelectrode arrays in emerging long-term implantable neural stimulation devices improves specificity, functionality, and performance of these devices. However, surgical site and post-implantation infections are amongst the most devastating complications after surgical procedures and implantations. Additionally, with the increased use of antibiotics, the threat of antibiotic resistance is significant and is increasingly being recognized as a global problem. Therefore, the need for alternative strategies to eliminate post-implantation infections and reduce antibiotic use has led to the development of medical devices with antibacterial properties. In this work, we report on the development of electrochemically active antibacterial platinum-iridium electrodes targeted for use in neural stimulation and sensing applications. A two-step development process was used. Electrodes were first restructured using femtosecond laser hierarchical surface restructuring. In the second step of the process, atomic layer deposition was utilized to deposit conformal antibacterial copper oxide thin films on the hierarchical surface structure of the electrodes to impart antibacterial properties to the electrodes with minimal impact on electrochemical performance of the electrodes. Morphological, compositional, and structural properties of the electrodes were studied using multiple modalities of microscopy and spectroscopy. Antibacterial properties of the electrodes were also studied, particularly, the killing effect of the hierarchically restructured antibacterial electrodes on Escherichia coli and Staphylococcus aureus-two common types of bacteria responsible for implant infections.

Biofabrication of Acer palmatum-Mediated Multifunctional CuO Nanoparticles for Dye Removal, Antibacterial-Antifungal Activity, and Molecular Docking

Copper oxide nanoparticles (CuONPs) are used in many fields from electronics to medicine due to their multifunctionality, and therefore, their production with environmentally friendly methods is a current issue. In this study, biofabricated CuONPs were obtained by using the leaf extract of Acer palmatum plant originating from the Far East to enlighten the characteristics of the novel nanoparticles differentiating from those existing in the literature. Multifunctional nature of the CuONPs was evaluated by the antibacterial, antifungal, and decolorative applications and also by performing molecular docking analysis. The fabricated CuONPs were characterized using ultraviolet-visible spectroscopy (UV-vis), Fourier-transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), and dynamic light scattering (DLS). The absorbance seen at 270 nm in the SPR band obtained by UV-vis spectroscopy proved the presence of CuONPs, while the 602, 560, and 540 cm-1 vibrations obtained in the FT-IR spectroscopy indicated the same result. SEM images proved that the nanoparticles were in spherical form with sizes ranging from 140 to 225 nm. The result of DLS analysis showed that the average particle size was 229 nm in diameter, and CuONPs had monodisperse systems (polydispersity index, 0.184). The dye removal potency of CuONPs was also investigated by using remazol brilliant blue R (RBBR) and napthol blue black (NBB). Decolorizations (74 and 86%) of RBBR and NBB were obtained in 90 min at 50 °C, respectively. The strong antibacterial properties of the synthesized CuONPs were observed on both Gram (-) and Gram (+) bacterial strains by disk diffusion and optical analyses, and their antifungal activity was close to that of Amphotericin B, which was applied as a positive control. Molecular docking analysis was performed with Escherichia coli dihydrofolate reductase and Staphylococcus aureus DNA Gyrase B to analyze the antibacterial mechanisms of CuONP and observed that they exhibit good interactions with their targets with binding energies of -12.562 and -8.797 kcal/mol, respectively. Our findings suggested that CuONPs are crucial in the mechanisms of folate metabolism and DNA replication associated with bacterial proliferation. This work will provide significant guidance for the biofabrication of CuONPs and their medical and industrial applications.

The Link between Trace Metal Elements and Glucose Metabolism: Evidence from Zinc, Copper, Iron, and Manganese-Mediated Metabolic Regulation

Trace metal elements are of vital importance for fundamental biological processes. They function in various metabolic pathways after the long evolution of living organisms. Glucose is considered to be one of the main sources of biological energy that supports biological activities, and its metabolism is tightly regulated by trace metal elements such as iron, zinc, copper, and manganese. However, there is still a lack of understanding of the regulation of glucose metabolism by trace metal elements. In particular, the underlying mechanism of action remains to be elucidated. In this review, we summarize the current concepts and progress linking trace metal elements and glucose metabolism, particularly for the trace metal elements zinc, copper, manganese, and iron.

Therapeutic Strategies against Biofilm Infections

A biofilm is an aggregation of surface-associated microbial cells that is confined in an extracellular polymeric substance (EPS) matrix. Infections caused by microbes that form biofilms are linked to a variety of animals, including insects and humans. Antibiotics and other antimicrobials can be used to remove or eradicate biofilms in order to treat infections. However, due to biofilm resistance to antibiotics and antimicrobials, clinical observations and experimental research clearly demonstrates that antibiotic and antimicrobial therapies alone are frequently insufficient to completely eradicate biofilm infections. Therefore, it becomes crucial and urgent for clinicians to properly treat biofilm infections with currently available antimicrobials and analyze the results. Numerous biofilm-fighting strategies have been developed as a result of advancements in nanoparticle synthesis with an emphasis on metal oxide np. This review focuses on several therapeutic strategies that are currently being used and also those that could be developed in the future. These strategies aim to address important structural and functional aspects of microbial biofilms as well as biofilms' mechanisms for drug resistance, including the EPS matrix, quorum sensing (QS), and dormant cell targeting. The NPs have demonstrated significant efficacy against bacterial biofilms in a variety of bacterial species. To overcome resistance, treatments such as nanotechnology, quorum sensing, and photodynamic therapy could be used.

Emerging Trends in Nanomaterials for Antibacterial Applications

Around the globe, surges of bacterial diseases are causing serious health threats and related concerns. Recently, the metal ion release and photodynamic and photothermal effects of nanomaterials were demonstrated to have substantial efficiency in eliminating resistance and surges of bacteria. Nanomaterials with characteristics such as surface plasmonic resonance, photocatalysis, structural complexities, and optical features have been utilized to control metal ion release, generate reactive oxygen species, and produce heat for antibacterial applications. The superior characteristics of nanomaterials present an opportunity to explore and enhance their antibacterial activities leading to clinical applications. In this review, we comprehensively list three different antibacterial mechanisms of metal ion release, photodynamic therapy, and photothermal therapy based on nanomaterials. These three different antibacterial mechanisms are divided into their respective subgroups in accordance with recent achievements, showcasing prospective challenges and opportunities in clinical, environmental, and related fields.

Effect of the Concentration and the Type of Dispersant on the Synthesis of Copper Oxide Nanoparticles and Their Potential Antimicrobial Applications

The bactericidal properties of copper oxide nanoparticles have growing interest due to potential application in the medical area. The present research investigates the influence of sodium dodecyl sulfate (SDS) and poly(vinylpyrrolidone) (PVP) on the production of copper oxide nanoparticles prepared from copper sulfate (CuSO₄) and sodium borohydride (NaBH₄) solutions. Different analytical techniques were used to determine the crystal nature, mean size diameter, and surface morphology of the copper oxide nanoparticles. The X-ray diffraction (XRD) patterns showed formation of nanoparticles of cuprite (Cu₂O) and tenorite (CuO) when PVP and SDS were added at the beginning of the reaction. In fact, when the Cu/PVP ratio was 1.62, Cu₂O nanoparticles were obtained. In addition, nanoparticles of CuO were synthesized when the Cu/PVP ratios were 0.54 and 0.81. On the other hand, a mixture of copper oxides (CuO and Cu₂O) and cuprite (Cu₂O) was obtained when PVP (Cu/PVP = 0.81 and 1.62) and SDS (Cu/SDS = 0.90) were added 30 min after the beginning of the reaction. Transmission electron microscopy (TEM) images show agglomerated nanoparticles with a size distribution ranging from 2 to 60 nm, while individual particles have sizes between 4.1 ± 1.9 and 41.6 ± 12.8 nm. The Kirby-Bauer method for the determination of antibacterial activity shows that small CuO (4.1 ± 1.9 nm) and Cu₂O (8.5 ± 5.3 nm) nanoparticles inhibit the growth of Escherichia coli, Staphylococcus aureus MRSA, S. aureus and Pseudomonas aeruginosa bacteria. The antibacterial test of cotton fabric impregnated with nanoparticles shows positive results. The determination of the optimal ratio of copper oxide nanoparticles per cm² of fabric that are able to exhibit a good antibacterial activity is ongoing.

Green synthesis of multifunctional carbon coated copper oxide nanosheets and their photocatalytic and antibacterial activities

The studies of metal oxides in environmental remediation of chemical and biological pollutants are gaining colossal importance. Herein, we report the facile synthesis of multifunctional copper oxide nanosheets (CuO NS) using an aqueous extract of Rhazya stricta. The phytochemical investigation of R. stricta indicated the presence of saponins, tannins, and reducing sugars, responsible for the reduction and stabilization of CuO NS. A UV–Visible spectrophotometer initially confirmed the fabrication of CuO NS with specific Surface Plasmon Resonance at 294 nm. Field Emission Scanning Electron Microscopy (FE-SEM), Fourier-transform infrared spectroscopy FTIR, and XRD were further used to characterize the CuO NS. The obtained CuO NS were poly-dispersed with an average size of 20 nm. Interestingly these particles were aligned together in 3D cubical sheets layered above each other via self-assembly. The as-synthesized CuO NS showed enhanced antibacterial potential (17.63 mm, overall mean inhibition zone) in comparison to the known antibiotics (11.51 mm, overall mean inhibition zone) against both Solanaceous crop's wilt-causing bacteria (Ralstonia solanacearum and Clavibacter michiganensis). Furthermore, the appreciable photocatalytic potential of CuO NS has also been observed, causing 83% degradation of methylene blue (MB) upon solar irradiation. The synthesis methodology is devoid of any toxic waste or by-products. It could be used to produce eco-friendly CuO nanomaterial for industrial uses.

Trachyspermum ammi and Cinnamomum verum as nutraceuticals: Spices rich in therapeutically significant protein tyrosine phosphatases

Nutraceuticals need special attention as preventive molecules to create a natural barrier against various dreadful diseases like cancer and to regulate metabolism. In the present study, two spices, Trachyspermum ammi and Cinnamomum verum, been identified as excellent Protein Tyrosine Phosphatases (PTPases) sources that play significant role in the regulation of cell signal transduction and developmental processes in plants as well as animals, being lucrative and potential targets for pharmacological modulation. PTPases from both cases were partially purified into 0%-40% and 40%-80% fractions based on ammonium sulfate saturation levels. Fraction (40%-80%) exhibited a purification level of 4.44-fold and 2.86-fold with specific activity of 44.06 and 23.33 U/mg for PTPases from T. ammi and C. verum, respectively. PTPases being found to be thermally stable up to 70°C imply their industrial significance. Kinetic studies showed K_m values to be 7.14 and 8.33 mM, whereas the activation energy (E_a ) values were 25.89 and 29.13 kJ/mol, respectively. Divalent cations: Cu²⁺ , Zn²⁺ , and Mn²⁺ acted as inhibitors of PTPases, from both sources. The K_i values of inhibitors varied from 0.014-0.125 mM in the descending order Cu²⁺  > Zn²⁺  > Mn²⁺ and Mn²⁺  > Cu²⁺  > Zn²⁺ for PTPases from T. ammi and C. verum, respectively. The inhibitory effect of sodium metavanadate aligns with prominent PTPase characteristics. In addition to these properties, the thermostability of PTPases from two spices enhances their significance in industries with therapeutically vital products. Although the source of PTPases is culinary spices, further studies are required to establish the utilization of PTPases as nutraceuticals and in therapeutic formulations. PRACTICAL APPLICATIONS: For a healthy lifestyle, awareness needs to be created by humankind towards food habits to minimize illnesses. Numerous studies have explored the consumption of nutraceutical products acts as a natural barrier and immune booster for various human ailments including SARS-COV-2. PTPases play important roles in regulating intracellular signaling and, ultimately, biological function along with their structural features. The importance of PTPases and their inhibitors has been implicated in various diseases like cancer, diabetes, and obesity. Further investigations need to be undertaken to explore the therapeutic properties of PTPases in both in vivo and in vitro for their clinical significance.

Copper Tannic Acid-Coordinated Metal-Organic Nanosheets for Synergistic Antimicrobial and Antifouling Coatings

The copper tannic acid (CuTA) nanosheets with an excellent antibacterial activity were successfully prepared, which showed fine antibacterial and antifouling performance after hybridization with acrylic resin. The morphology and structure characterization of CuTA nanosheets were studied by transmission electron microscopy, scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, thermogravimetric analysis, etc. The plate counting method, zone of inhibition test, and minimum inhibitory concentration (MIC) method were used to detect the antibacterial activity of the prepared samples against Gram-positive Bacillus subtilis (B. subtilis) and Gram-negative Escherichia coli (E. coli). The results showed that the killing rates of 2 and 0.5 mg/mL of CuTA powder were close to 100% after 24 h. The MIC values of E. coli and B. subtilis were 0.25 and 0.5 mg/mL, respectively. The results of morphology and element distribution of bacteria, after treating with CuTA powder, revealed that Cu²⁺ and TA destroyed their cell walls and inhibited the proliferation and growth of the bacteria. Furthermore, the hybrid coating of CuTA nanosheets and acrylic resin showed brilliant antimicrobial performance for E. coli and B. subtilis and antialgae properties under a lower CuTA load (≤5%). The CuTA nanosheets with a low copper content (30.9 wt %) and low pollution have promising applications in marine antifouling coatings.

Enhanced Biosynthesis Synthesis of Copper Oxide Nanoparticles (CuO-NPs) for their Antifungal Activity Toxicity against Major Phyto-Pathogens of Apple Orchards

PURPOSE

The present study made an attempt to develop copper nanoparticles (Cu-NP) with antifungal property using green synthesis method. Copper oxide nanoparticles (CuO-NPs) botanically synthesized using Neem leaf extract (Azadirachta indica A. Juss) were characterized by using different techniques like; UV-visible spectrophotometry, FTIR, XRD, SEM and TEM.

METHODS

Materials were chosen the disease free and fresh Azadirachta indica A. Juss were collected and identified at Center of Biodiversity and Taxonomy. The plant samples were vigorously washed with distilled water then shade dried followed by sterilization with 0.1% mercuric chloride for 20 s and again it was washed with distilled water. 15 g powder form of plant material was added to 200 ml double distilled, CO₂ free and deionized water and kept in shaker at 80°C and 1500 rpm for six hours. After agitation, the extract was separated by regular centrifugation at 10,000 rpm followed by filtration by using whatmann filter paper. The final volume of 100 ml of supernatant was collected as pure extract and stored in cool place for further use.

RESULTS

The final results confirm a significant inhibition of CuO-NPs for the test fungi. Additionally, CuO-NPs demonstrated an enhanced effect when combined with Neem leaf extract. A total of 20-30% improvement in activity was noticed after combination, which correlates with commonly used synthetic fungicides. The toxicity results reveal that A. indica extract and their combined fractions with CuO-NP were less toxic to the test seeds of experimental plant while as bulk Cu followed by biosynthesized CuO-NPs influenced the germination rate as compared to control pots.

CONCLUSIONS

The study drops a concern of research and offers a promising route of developing Copper based green fungicides that can help to combat with modern issues of synthetic fungicides. An average size of 80 ± 15 nm monoclinic cupric oxide (CuO) and cubic cuprous oxides (Cu₂O) nanocrystals that existed in mixed form were successfully developed.

Metal Oxide Nanoparticles Against Bacterial Biofilms: Perspectives and Limitations

At present, there is an urgent need in medicine and industry to develop new approaches to eliminate bacterial biofilms. Considering the low efficiency of classical approaches to biofilm eradication and the growing problem of antibiotic resistance, the introduction of nanomaterials may be a promising solution. Outstanding antimicrobial properties have been demonstrated by nanoparticles (NPs) of metal oxides and their nanocomposites. The review presents a comparative analysis of antibiofilm properties of various metal oxide NPs (primarily, CuO, Fe3O4, TiO2, ZnO, MgO, and Al2O3 NPs) and nanocomposites, as well as mechanisms of their effect on plankton bacteria cells and biofilms. The potential mutagenicity of metal oxide NPs and safety problems of their wide application are also discussed.

In Vitro Assessment Antiparasitic Effect of Selenium and Copper Nanoparticles on Giardia deodenalis Cyst

Background:

Application of chemotherapy to treatment of parasitic disease of man and animals can be problematic due to different adverse effects. As a result, there is an increasing interest in nanoparticles as new therapeutic tools against these diseases. This study was designed to evaluate the effect of selenium and copper oxide nanoparticles on Giardia deudenalis cysts in vitro, as well as comparing it to that of metronidazole.

Methods:

The cysts were taken from the stools of patients in Urmia, Iran, during 2017–2018. The cysts were taken from stool and were concentrated and isolated on 0.85 M-sucrose. Then, selenium and copper oxide nanoparticles were prepared at concentrations of 0.15, 0.3, and 0.6 mg/ml. The effect of nanoparticle’s various concentrations at 10, 15, 30, 60, and 180 min were evaluated and compared to control groups. Obtained data was recorded and statistically analyzed.

Results:

Copper oxide nanoparticles at a concentration of 0.6 mg/ml and selenium nanoparticles at a concentration of 0.3 mg/ml had the same effect as of metronidazole in killing of Giardia cysts. The cytotoxic effects of selenium and copper oxide nanoparticles, compared with metronidazole, on Giardia cysts, showed an increase of fatality rate due to extend exposure time and nanoparticle’s concentration (P<0.05).

Conclusion:

Selenium and copper oxide nanoparticles are as efficient as metronidazole, for killing Giardia cysts in vitro.

Organic and inorganic antibacterial approaches in combating bacterial infection for biomedical application

In spite of antibiotics, antibacterial agents or specifically known as antiseptics are actively explored for the prevention of infection-associated medical devices. Antibacterial agents are introduced to overcome the complication of bacterial resistance which devoted by antibiotics. It can be classified into inorganic and organic, that prominently have impacted bacterial retardation in their own killing mechanism patterns. Therefore, this review paper aimed to provide information on most common used inorganic and organic antibacterial agents which have potential to be utilized in biomedical applications, thus, classifying the trends of antibacterial mechanism on Gram-negative and Gram-positive bacteria. In the beginning, infectious diseases and associated biomedical infections were stated to expose current infection scenarios on medical devices. The general view, application, susceptible bacteria and activation mechanism of inorganic (silver, copper, gold and zinc) and organic (chlorhexidine, triclosan, polyaniline and polyethylenimine) antibacterial agents that are widely proposed for biomedical area, were then gathered and reviewed. In the latter part of the study, the intact mechanisms of inorganic and organic antibacterial agents in retarding bacterial growth were classified and summarized based on its susceptibility on Gram-negative and Gram-positive bacteria. Most of inorganic antibacterial agents are in the form of metal, which release its ions to retard prominently Gram-negative bacteria. While organic antibacterial agents are susceptible to Gram-positive bacteria through organelle modification and disturbance of bio-chemical pathway. However, the antibacterial effects of each antibacterial agent are also depending on its effective mechanism and the species of bacterial strain. These compilation reviews and classification mechanisms are beneficial to assist the selection of antibacterial agents to be incorporated on/within biomaterials, based on its susceptible bacteria. Besides, the combination of several antibacterial agents with different susceptibilities will cover a wide range of antibacterial spectrum.

Non-redox cycling mechanisms of oxidative stress induced by PM metals

Metallic compounds contribute to the oxidative stress of ambient particulate matter (PM) exposure. The toxicity of redox inert ions of cadmium, mercury, lead and zinc, as well as redox-active ions of vanadium and chromium is underlain by dysregulation of mitochondrial function and loss of signaling quiescence. Central to the initiation of these effects is the interaction of metal ions with cysteinyl thiols on glutathione and key regulatory proteins, which leads to impaired mitochondrial electron transport and persistent pan-activation of signal transduction pathways. The mitochondrial and signaling effects are linked by the production of H₂O₂, generated from mitochondrial superoxide anion or through the activation of NADPH oxidase, which extends the range and amplifies the magnitude of the oxidative effects of the metals. This oxidative burden can be further potentiated by inhibitory effects of the metals on the enzymes of the glutathione and thioredoxin systems. Along with the better-known Fenton-based mechanisms, the non-redox cycling mechanisms of oxidative stress induced by metals constitute significant pathways for cellular injury induced by PM inhalation.

Green Synthesis, Characterization and Antimicrobial Activity of Copper Oxide Nanomaterial Derived from Momordica charantia

Background

In the emerging field of nanotechnology, copper oxide (CuO) nanomaterials are considered to be one of the most important transition metal oxides owing to its fascinating properties. Its synthesis from green chemistry principles is gaining importance as next-generation antibiotics due to its simplicity, eco-friendliness, and cost-effectiveness. In the present study, CuO nanorods (CuO NRs) were synthesized from the aqueous fruit extract of Momordica charantia and characterized using different analytical techniques. Further, the biomedical therapeutic potential was evaluated against multi-drug resistant microbial strains.

Materials and Methods

To synthesize CuO NRs, 0.1M of CuSO₄.5H₂O solution was added to aqueous extract of Momordica charantia in a 1:3 (v/v) ratio (pH=11) and heated at 50°C followed by washing and drying. The synthesized CuO NRs were subjected to characterization using different analytical techniques such as UV visible spectroscopy, zeta sizer equipped with zeta potential, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM) equipped with energy-dispersive X-ray spectroscopy (EDS) and transmission electron microscopy (TEM). Further, the application as a biomedical therapeutic potential was evaluated in vitro using well diffusion method against eleven multidrug-resistant clinical bacterial strains, a fungus- Trichophyton rubrum and in ovo against the R₂B virus using haemagglutination (HA) test.

Results

Characterization was preliminarily done by the spectral study that confirms the absorbance band at 245nm. FTIR analysis at 628 cm⁻¹ peak identified copper oxide vibration. SEM analysis revealed agglomerated particle clusters. However, with TEM clear nanorods of average diameter of 61.48 ± 2 nm were observed. EDAX confirmed CuO formation while XRD showed a typical monoclinic structure with 6 nm crystallite size. Biological screening of CuO NRs showed significant results against both in vitro and in ovo methods. Significant inhibitory activity (p<0.0001) was noted against most of the resistant human pathogenic strains including both Gram-positive and Gram-negative bacteria. The highest efficacy was observed against Bacillus cereus with a 31.66 mm zone of inhibition. Besides, the therapeutic potential of CuO NRs against Corynebacterium xerosis, Streptococcus viridians and R₂B strain of Newcastle disease is reported for the first time.

Conclusion

Based on the present results, it could be expected that green synthesized CuO NRs would find potential applications in the field of nanomedicine.

Synthesis of biologically active copper oxide nanoparticles as promising novel antibacterial-antibiofilm agents

In this study, we aimed to synthesize copper oxide nanoparticles (CuONPs) mediated by plant extract in an environmentally friendly way and to reveal their potential biological activities. Here we synthesized CuONPs by using different concentrations of aqueous leaf extract of Thymbra spicata at 80 °C to obtain Ts1CuONPs and Ts2CuONPs. Biosynthesized nanoparticles were characterized by using UV-Vis, AFM, FTIR, SEM-EDS, TEM, DLS and zeta potential analysis. The antibacterial activity of the nanoparticles was determined by calculation of the inhibition zone and minimum inhibitory concentration against selected bacterial strains. Moreover, the antioxidant activity of the as-synthesized nanoparticles was evaluated based on DPPH radical scavenging activity. The results indicate that the as-synthesized NPs have an average size of 26.8 and 21 nm for Ts1CuONPs and Ts2CuONPs, respectively. The formed CuONPs have more antibacterial action on gram-positive bacteria compared to gram-negative bacteria. In addition, CuONPs demonstrated good inhibition activity against biofilm formation of Staphylococcus aureus (S. aureus). Furthermore, the results showed that the smaller size of the CuONPs caused the higher cytotoxicity on L929 mouse fibroblast cells. The as-synthesized CuONPs exhibit antibacterial and antibiofilm potential against S. aureus, indicating that they may be attractive candidates to use in future therapeutic applications.

Immobilization of Microalgae

Several microalgae synthesize metabolites of great commercial interest. Microalgae also act as filters for wastewater N and P, heavy metals, and xenobiotic compounds. However, the cost-effective harvesting of microalgae is one of the major bottlenecks limiting the microalgal biomass applications. In this context, immobilization of algal cells has been proposed for circumventing the harvest problem as well as retaining the high-value algal biomass for further processing. In recent years, innovative approaches have been employed in the field of coimmobilization and microencapsulation, which have proved the superiority of immobilized cells over the free cells. Further, the development in the field of biosensor technology with immobilized microalgae presents an early warning device to monitor pollutants in natural waters. This chapter reviews the various applications of immobilized microalgae and addresses the specific methods concerning the production of coimmobilized beads and the protocol for construction of optical algal biosensors.

Antiprotozoal activity of silver nanoparticles against Cryptosporidium parvum oocysts: New insights on their feasibility as a water disinfectant

Cryptosporidium is a protozoan of extremely medical and veterinary impact; whose oocysts donate a considerable resistant to the water treatment processes. Therefore, this study aimed to explore the impacts of silver nanoparticles (AgNPs) on count and viability of the Cryptosporidium parvum (CP) isolated from different tap water samples. The oocysts were exposed to AgNPs at different dosages of 0.05, 0.1 and 1 ppm for several contact times (30 min to 4 h). The results showed a significant decrease in oocyst count and viability in a dose-dependent manner. Additionally, AgNPs at a conc. of 1 ppm for 30 min and 0.1 ppm for 1 h reduced the oocysts by 97.2 and 94.4%, respectively. Comparatively, there was a noticeable increase in the oocyst's viability at 2 and 4 h, which emphasized that the time of contact between AgNPs and CP was not a major influencing factor for successful application of AgNPs in the nano-water treatment.

The Use of Copper as an Antimicrobial Agent in Health Care, Including Obstetrics and Gynecology

Health care-associated infections (HAIs) are a global problem associated with significant morbidity and mortality. Controlling the spread of antimicrobial-resistant bacteria is a major public health challenge, and antimicrobial resistance has become one of the most important global problems in current times. The antimicrobial effect of copper has been known for centuries, and ongoing research is being conducted on the use of copper-coated hard and soft surfaces for reduction of microbial contamination and, subsequently, reduction of HAIs. This review provides an overview of the historical and current evidence of the antimicrobial and wound-healing properties of copper and explores its possible utility in obstetrics and gynecology.

Copper Oxide Nanomaterials Derived from Zanthoxylum armatum DC. and Berberis lycium Royle Plant Species: Characterization, Assessment of Free Radical Scavenging and Antibacterial Activity

Copper oxide nanomaterials were synthesized by a facile sustainable biological method using two plant species (Zanthoxylum armatum DC. and Berberis lycium Royle). The formation of materials was confirmed by FT-IR, ATR, UV-visible, XRD, TEM, SEM, EDX, TGA and PL. The antibacterial activity was evaluated by agar well diffusion method to ascertain the efficacy of plant species extract and extract derived copper oxide nanomaterials against six Gram-positive bacteria namely Staphylococcus aureus, Streptococcus mutans, Streptococcus pyogenes, Corynebacterium diphtheriae, Corynebacterium xerosis, Bacillus cereus and four Gram-negative bacteria such as Klebsiella pneumonia, Escherichia coli, Pseudomonas aeruginosa and Proteus vulgaris against the standard drug, Ciprofloxacin for Gram-positive and Gentamicin for Gram-negative bacteria, respectively. In both cases, copper oxide nanomaterials were found to be sensitive in all the bacterial species. Sensitivity of copper oxide nanomaterials shows an be higher as compared to plant species extract against different bacteria. Scavenging activity of plant extracts along with nanomaterials have been accessed using previously reported protocols employing ascorbic acid as standard. Scavenging activity of copper oxide nanomaterials shows an increase with increase in concentration. The biological activity (bactericidal and scavenging efficiency) of plant derived copper oxide nanomaterials revealed that these materials can be used as potent antimicrobial agent and DPPH scavengers in industrial as well as pharmacological fields.

Antibacterial activity of ZnO and CuO nanoparticles against gram positive and gram negative strains

This is a report on the antibacterial activity of ZnO and CuO nanoparticles synthesized via sol-gel method. The studies were performed on Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli and Pseudomonas aeruginosa bacteria using disc and well diffusion methods, bioluminescence and optical density analysis. The results show a strong decline of bacterial strains after a short contact with nanoparticles. The modelling allowed clarifying the bacterial sensitivity of toxic agents at different stages of their population evolution kinetics. It was concluded that the bacterial suppression is most effective at the exponential growth phase while it is of a lower effectiveness at the lag and stationary phases. The CuO and ZnO nanoparticles showed comparable effectiveness at the exponential growth phase. In the same time, ZnO was almost inactive at the lag phase and of lower effectiveness at the stationary phase, at which CuO conserved a significant activity.

Green synthesis of CuO nanomaterials and their proficient use for organic waste removal and antimicrobial application

Copper oxide (CuO) nanomaterials (NMs) of different size and morphology were synthesized by Chemical precipitation, Microwave irradiation and Hydrothermal method and characterized by TEM, BET, FTIR, XRD and EDX analysis. As synthesized CuO NMs were utilized for elimination of harmful dyes viz. Direct Red 81 (DR-81) and Coomassie Brilliant blue R-250 (BBR-250) and pathogenic bacteria (Staphylococcus aureus). Owing to their morphology, smaller size and relatively high surface area (40.320 m² g^-1), CuO NMs prepared by chemical precipitation method were observed to show better adsorption capacity for both the dyes (68.70 (DR-81) and 73.04 (BBR-250) mg g^-1). The influence of different experimental conditions was studied by the methodical assessments of various parameters such as pH, adsorbent dose, concentration and contact time. Moreover, different adsorption isotherms and pseudo-second order kinetic model were applied to understand the adsorption mechanism. Langmuir model was found to be best fit thus confirming the monolayer adsorption process. To ensure the practical utility of CuO NMs for organic waste removal, the adsorption studies were performed in the presence of different inorganic ions and real water samples. In addition, recovery of the dye and NMs were also carried out effectively by simple method, thus avoiding the secondary pollution. CuO NMs were observed to exhibit significant antibacterial activity against the human pathogenic bacteria. These studies demonstrated that synthesized CuO NMs showed good adsorption efficiency for the removal of harmful dyes and antimicrobial activity against the pathogenic bacteria, which vary as a function of size and surface area.

Assessment of biotoxicity of Cu nanoparticles with respect to probiotic strains of microorganisms and representatives of the normal flora of the intestine of broiler chickens

Copper nanoparticle Cu (d = 55 ± 15 nm) and CuO nanoparticles (d = 90 ± 10 nm) were used in the studies (OOO Platina, Russia). Using the method of pure cultures, we extracted Lactobacillus, Enterococcus, and Enterobacterium from the intestines of broilers. Additionally, strains of Bacillus subtilis 10641 and Bifidobacterium were involved in probiotic strains. The data obtained in the course of the study testify to the insignificant biotoxicity of copper nanoparticles with respect to representatives of the genera Lactobacillus (30 to 15 μg/ml) and Bifidobacterium (30 μg/ml), with the most sensitive bacteria being the genus Lactobacillus, for which a concentration of 7.5 μg/ml was subinhibitory. The second stage was the study using method of agar wells. In the course of the experiment, we obtained results confirming the data of the research by the serial dilution method. In this case, as in the first case, the data indicate the insignificant biotoxicity of copper nanoparticles in relation to representatives of the genera Lactobacillus and Bifidobacterium. We have studied the bioaccumulating ability of microorganisms of the studied metals. In all the studies carried out, as in the first series of experiments, representatives of the genera Lactobacillus and Bifidobacterium with the lowest bioaccumulative ability were the most sensitive to copper nanoparticles and were 3.1 and 8.2%, respectively. The use of nanoparticles as a component of the fodder additive in small concentrations does not adversely affect not only the probiotic strains, but also the main representatives of the normoflora (Lactobacillus, Enterococcus, and Enterobacterium) of the poultry, the positive effect of the copper nanoparticles being directly related to low level of dissociation of nanoparticles, since biologically active ions will be released much more slowly, thereby creating a prolonged effect of exposure.

Covalent inhibition of protein tyrosine phosphatases

Protein tyrosine phosphatases (PTPs) are a large family of 107 signaling enzymes that catalyze the hydrolytic removal of phosphate groups from tyrosine residues in a target protein. The phosphorylation status of tyrosine residues on proteins serve as a ubiquitous mechanism for cellular signal transduction. Aberrant function of PTPs can lead to many human diseases, such as diabetes, obesity, cancer, and autoimmune diseases. As the number of disease relevant PTPs increases, there is urgency in developing highly potent inhibitors that are selective towards specific PTPs. Most current efforts have been devoted to the development of active site-directed and reversible inhibitors for PTPs. This review summarizes recent progress made in the field of covalent inhibitors to target PTPs. Here, we discuss the in vivo and in vitro inactivation of various PTPs by small molecule-containing electrophiles, such as Michael acceptors, α-halo ketones, epoxides, and isothiocyanates, etc. as well as oxidizing agents. We also suggest potential strategies to transform these electrophiles into isozyme selective covalent PTP inhibitors.

DUSP3/VHR: A Druggable Dual Phosphatase for Human Diseases

Protein tyrosine kinases (PTK), discovered in the 1970s, have been considered master regulators of biological processes with high clinical significance as targets for human diseases. Their actions are countered by protein tyrosine phosphatases (PTP), enzymes yet underrepresented as drug targets because of the high homology of their catalytic domains and high charge of their catalytic pocket. This scenario is still worse for some PTP subclasses, for example, for the atypical dual-specificity phosphatases (ADUSPs), whose biological functions are not even completely known. In this sense, the present work focuses on the dual-specificity phosphatase 3 (DUSP3), also known as VH1-related phosphatase (VHR), an uncommon regulator of mitogen-activated protein kinase (MAPK) phosphorylation. DUSP3 expression and activities are suggestive of a tumor suppressor or tumor-promoting enzyme in different types of human cancers. Furthermore, DUSP3 has other biological functions involving immune response mediation, thrombosis, hemostasis, angiogenesis, and genomic stability that occur through either MAPK-dependent or MAPK-independent mechanisms. This broad spectrum of actions is likely due to the large substrate diversity and molecular mechanisms that are still under scrutiny. The growing advances in characterizing new DUSP3 substrates will allow the development of pharmacological inhibitors relevant for possible future clinical trials. This review covers all aspects of DUSP3, since its gene cloning and crystallographic structure resolution, in addition to its classical and novel substrates and the biological processes involved, followed by an update of what is currently known about the DUSP3/VHR-inhibiting compounds that might be considered potential drugs to treat human diseases.

Silver nanoparticle embedded copper oxide as an efficient core–shell for the catalytic reduction of 4-nitrophenol and antibacterial activity improvement

A facile and eco-friendly method was developed to prepare a microporous CuO@Ag⁰ core–shell with high catalytic and antibacterial activities.

Green Adeptness in the Synthesis and Stabilization of Copper Nanoparticles: Catalytic, Antibacterial, Cytotoxicity, and Antioxidant Activities

Copper nanoparticles (CuNPs) are of great interest due to their extraordinary properties such as high surface-to-volume ratio, high yield strength, ductility, hardness, flexibility, and rigidity. CuNPs show catalytic, antibacterial, antioxidant, and antifungal activities along with cytotoxicity and anticancer properties in many different applications. Many physical and chemical methods have been used to synthesize nanoparticles including laser ablation, microwave-assisted process, sol-gel, co-precipitation, pulsed wire discharge, vacuum vapor deposition, high-energy irradiation, lithography, mechanical milling, photochemical reduction, electrochemistry, electrospray synthesis, hydrothermal reaction, microemulsion, and chemical reduction. Phytosynthesis of nanoparticles has been suggested as a valuable alternative to physical and chemical methods due to low cytotoxicity, economic prospects, environment-friendly, enhanced biocompatibility, and high antioxidant and antimicrobial activities. The review explains characterization techniques, their main role, limitations, and sensitivity used in the preparation of CuNPs. An overview of techniques used in the synthesis of CuNPs, synthesis procedure, reaction parameters which affect the properties of synthesized CuNPs, and a screening analysis which is used to identify phytochemicals in different plants is presented from the recent published literature which has been reviewed and summarized. Hypothetical mechanisms of reduction of the copper ion by quercetin, stabilization of copper nanoparticles by santin, antimicrobial activity, and reduction of 4-nitrophenol with diagrammatic illustrations are given. The main purpose of this review was to summarize the data of plants used for the synthesis of CuNPs and open a new pathway for researchers to investigate those plants which have not been used in the past. Graphical abstract Proposed Mechanism for Antibacterial activity of copper nanoparticles.

Expression, purification, and characterization of a novel acid phosphatase that displays protein tyrosine phosphatases activity from Metarhizium anisopliae strain CQMa102

The protein tyrosine phosphatase (PTPase) plays an important role in insect immune system. Our group has purified a type of acid phosphatase that could specifically dephosphorylate trans-Golgi p230 in vitro. In order to study this phosphatase further, we have identified and cloned the phosphatase gene from a locust specific Metarhizium anisopliae Strain CQMa102. The CQMa102 phosphatase was expressed in Pichia pastoris to verify its protease activity. The molecular weight (MW) and the isoelectric point (pI) of the phosphatase were about 85 kDa and 6.15, respectively. Substrate specificity evaluation showed that the purified enzyme exhibited high activity on O-phospho-L-tyrosine. At its optimal pH of 6.5 and optimum temperature of 70 °C, the protein showed the highest activity respectively. It can be activated by Ca2+, Mg2+, Mn2+, Ba2+, Co2+ and phosphate analogs, but inhibited by Zn2+, Cu2+, fluoride, dithiothreitol, β-mercaptoethanol and N-ethylmaleimide.

Novel Durable Antimicrobial Ceramic with Embedded Copper Sub-Microparticles for a Steady-State Release of Copper Ions

Using pottery clay, porous ceramic stones were molded and then decorated with copper sub-microparticles inside the pores. Copper added antimicrobial functionality to the clay-based ceramic and showed ability in disinfecting water. Populations of both Staphylococcus aureus and Klebsiella pneumoniae in contaminated water were reduced by >99.9% in 3 h when exposed to an antimicrobial stone. This antimicrobial performance is attributed to a slow release of copper into water at both room and elevated temperatures. Copper is leached by water to produce ion concentrations in water at a level of 0.05–0.20 ppm after 24 to 72 h immersion tests. This concentration is reproducible over a number of cycles >400. To our knowledge, this is the first formulation of copper sub-microparticles inside the porous structure of commercial-sized ceramic stones that can disinfect bacteria-contaminated water over a period of at least several months.

The role of copper nanoparticles in an etch-and-rinse adhesive on antimicrobial activity, mechanical properties and the durability of resin-dentine interfaces

OBJECTIVES

To evaluate the effect of addition of copper nanoparticles at different concentrations into an etch-and-rinse adhesive (ER) on antimicrobial activity, Knoop microhardness (KHN), in vitro and in situ degree of conversion (DC), as well as the immediate (IM) and 2-year (2Y) resin-dentine bond strength (μTBS) and nanoleakage (NL).

METHODS

Seven experimental ER adhesives were formulated according to the amount of copper nanoparticles incorporated into the adhesives (0 [control], 0.0075 to 1wt.%). We tested the antimicrobial activity of adhesives against Streptococcus mutans using agar diffusion assay after IM and 2Y. The Knoop microhardness and in vitro DC were tested after IM and 2Y. The adhesives were applied to flat occlusal dentine surfaces after acid etching. After resin build-ups, specimens were longitudinally sectioned to obtain beam-like resin-dentine specimens (0.8mm²), which were used for evaluation of μTBS and nanoleakage at the IM and 2Y periods. In situ DC was evaluated at the IM period in these beam-like specimens. Data were submitted to appropriate statistical analyses (α=0.05).

RESULTS

The addition of copper nanoparticles provided antimicrobial activity to the adhesives only in the IM evaluation and slightly reduced the KHN, the in vitro and in situ DC (copper concentrations of 1wt.%). However, KHN increase for all concentrations after 2Y. After 2Y, no significant reductions of μTBS (0.06 to 1% wt.%) and increases of nanoleakage were observed for copper containing adhesives compared to the control group.

CONCLUSION

Copper nanoparticles addition up to 0.5wt.% may provide antimicrobial properties to ER adhesives and prevent the degradation of the adhesive interface, without reducing the mechanical properties of the formulations.

Antimicrobial organic–inorganic composite membranes including sepiolite-supported nanometals

In this study, composite polysulfone–polyvinylpyrrolidone (PSU–PVP) membranes were prepared using silver and copper loaded sepiolite as a filler.

The Inorganic Side of NGF: Copper(II) and Zinc(II) Affect the NGF Mimicking Signaling of the N-Terminus Peptides Encompassing the Recognition Domain of TrkA Receptor

The nerve growth factor (NGF) N-terminus peptide, NGF(1–14), and its acetylated form, Ac-NGF(1–14), were investigated to scrutinize the ability of this neurotrophin domain to mimic the whole protein. Theoretical calculations demonstrated that non-covalent forces assist the molecular recognition of TrkA receptor by both peptides. Combined parallel tempering/docking simulations discriminated the effect of the N-terminal acetylation on the recognition of NGF(1–14) by the domain 5 of TrkA (TrkA-D5). Experimental findings demonstrated that both NGF(1–14) and Ac-NGF(1–14) activate TrkA signaling pathways essential for neuronal survival. The NGF-induced TrkA internalization was slightly inhibited in the presence of Cu²⁺ and Zn²⁺ ions, whereas the metal ions elicited the NGF(1–14)-induced internalization of TrkA and no significant differences were found in the weak Ac-NGF(1–14)-induced receptor internalization. The crucial role of the metals was confirmed by experiments with the metal-chelator bathocuproine disulfonic acid, which showed different inhibitory effects in the signaling cascade, due to different metal affinity of NGF, NGF(1–14) and Ac-NGF(1–14). The NGF signaling cascade, activated by the two peptides, induced CREB phosphorylation, but the copper addition further stimulated the Akt, ERK and CREB phosphorylation in the presence of NGF and NGF(1–14) only. A dynamic and quick influx of both peptides into PC12 cells was tracked by live cell imaging with confocal microscopy. A significant role of copper ions was found in the modulation of peptide sub-cellular localization, especially at the nuclear level. Furthermore, a strong copper ionophoric ability of NGF(1–14) was measured. The Ac-NGF(1–14) peptide, which binds copper ions with a lower stability constant than NGF(1–14), exhibited a lower nuclear localization with respect to the total cellular uptake. These findings were correlated to the metal-induced increase of CREB and BDNF expression caused by NGF(1–14) stimulation. In summary, we here validated NGF(1–14) and Ac-NGF(1–14) as first examples of monomer and linear peptides able to activate the NGF-TrkA signaling cascade. Metal ions modulated the activity of both NGF protein and the NGF-mimicking peptides. Such findings demonstrated that NGF(1–14) sequence can reproduce the signal transduction of whole protein, therefore representing a very promising drug candidate for further pre-clinical studies.

The metal face of protein tyrosine phosphatase 1B

A new paradigm in metallobiochemistry describes the activation of inactive metalloenzymes by metal ion removal. Protein tyrosine phosphatases (PTPs) do not seem to require a metal ion for enzymatic activity. However, both metal cations and metal anions modulate their enzymatic activity. One binding site is the phosphate binding site at the catalytic cysteine residue. Oxyanions with structural similarity to phosphate, such as vanadate, inhibit the enzyme with nanomolar to micromolar affinities. In addition, zinc ions (Zn2+) inhibit with picomolar to nanomolar affinities. We mapped the cation binding site close to the anion binding site and established a specific mechanism of inhibition occurring only in the closed conformation of the enzyme when the catalytic cysteine is phosphorylated and the catalytic aspartate moves into the active site. We discuss this dual inhibition by anions and cations here for PTP1B, the most thoroughly investigated protein tyrosine phosphatase. The significance of the inhibition in phosphorylation signaling is becoming apparent only from the functions of PTP1B in the biological context of metal cations as cellular signaling ions. Zinc ion signals complement redox signals but provide a different type of control and longer lasting inhibition on a biological time scale owing to the specificity and affinity of zinc ions for coordination environments. Inhibitor design for PTP1B and other PTPs is a major area of research activity and interest owing to their prominent roles in metabolic regulation in health and disease, in particular cancer and diabetes. Our results explain the apparent dichotomy of both cations (Zn2+) and oxyanions such as vanadate inhibiting PTP1B and having insulin-enhancing ("anti-diabetic") effects and suggest different approaches, namely targeting PTPs in the cell by affecting their physiological modulators and considering a metallodrug approach that builds on the knowledge of the insulin-enhancing effects of both zinc and vanadium compounds.

Protective hybrid coating containing silver, copper and zinc cations effective against human immunodeficiency virus and other enveloped viruses

Background

Healthcare-acquired infections by pathogenic microorganisms including viruses represent significant health concern worldwide. Next to direct transmission from person-to-person also indirect transmission from contaminated surfaces is well documented and important route of infections. Here, we tested antiviral properties of hybrid coating containing silver, copper and zinc cations that was previously shown to be effective against pathogenic bacteria including methicillin-resistant Staphylococcus aureus. Hybrid coatings containing silver, copper and zinc cations were prepared through radical polymerization via sol-gel method and applied on glass slides or into the wells of polymethylmethacrylate plates. A 10 μl droplet of several viruses such as human immunodeficiency virus type 1 (HIV-1), influenza, dengue virus, herpes simplex virus, and coxsackievirus was added to coated and uncoated slides or plates, incubated usually from 5 to 240 min and followed by titer determination of recovered virus.

Results

Scanning electron microscopy analysis showed better adhesion of coatings on glass surfaces, which resulted in 99.5–100 % HIV-1 titer reduction (3.1 ± 0.8 log₁₀TCID₅₀, n = 3) already after 20 min of exposure to coatings, than on coated polymethylmethacrylate plates with 75–100 % (1.7 ± 1.1 log₁₀TCID₅₀, n = 3) and 98–100 % (2.3 ± 0.5 log₁₀TCID₅₀, n = 3) HIV-1 titer reduction after 20 and 120 min of exposure, respectively. Slower virucidal kinetics was observed with other enveloped viruses, where 240 min exposure to coated slides lead to 97 % (dengue), 100 % (herpes simplex) and 77 % (influenza) reduction in virus titers. Interestingly, only marginal reduction in viral titer after 240 min of exposure was noticed for non-enveloped coxsackie B3 virus.

Conclusions

Our hybrid coatings showed virucidal activity against HIV and other enveloped viruses thus providing further findings towards development of broad-spectrum antimicrobial coating suitable for surfaces in healthcare settings.

2-Imino-(3,4-dimethoxybenzyl) ethanesulfonic acid Schiff base anchored silver nanocomplex mediated by sugarcane juice and their antibacterial activities

In this present investigation, 2-imino-(3,4-dimethoxybenzyl)ethane sulphonic acid was anchored on a silver nanoparticle mediated by sugarcane sap. The Schiff base was synthesized from 2-aminoethanesulphonic acid and 3,4-dimethoxybenzaldehyde under lemon juice catalyzed conditions while the nanoparticles were obtained by careful stirring of sugarcane sap and 1 mM AgNO₃ in the ratio of 1:10 respectively at room temperature. The resulting nanocomplex was formed by gentle heating and stirring of the silver nanoparticles solution and the ligand at a temperature of about 80 °C for 3 h. The ligand, nanoparticles and nanocomplex were characterized using UV–vis spectrophotometer, scanning electron microscope, FT-IR and XRD machines. From the UV–vis results, surface plasmon bands (SPBs) were observed at 475 nm for the nanoparticle within 1 h of the reaction and 450 nm for the nanocomplex. The ligand exhibited absorption bands at 310 nm, 280 nm and 230 nm which are due to π-electron transitions within the chromophores. The strikingly broad nature of the SPBs especially in the nanoparticles revealed that the particles are kinetically favored, nucleate easily and are polydispersed and the blue shift observed in the nanocomplex suggested further reduction in the particle size therefore giving us a clue on how to tailor the products by tuning the raw materials. From the scanning electron micrographs, the morphologies and growth mechanisms revealed oriented attachment for the nanoparticles onwards digestive ripening for the nanocomplex. All the synthesized materials proved to be potential antibacterial agents as they showed great inhibition to the growth of some bacterial strains with the activity enhanced in the nanocomplex.

Bioactive and biocompatible copper containing glass-ceramics with remarkable antibacterial properties and high cell viability designed for future in vivo trials

The efficiency of 60SiO₂·(32 − x) CaO·8P₂O₅·xCuO (mol%) glass-ceramics were proved, and was determined the most appropriate composition for further in vivo trials.