Assessment of antibacterial efficacy of a biocompatible nanoparticle PC@AgNPs against Staphylococcus aureus

Effects of PEF on Cell and Transcriptomic of Escherichia coli

Pulsed electric field (PEF) is an up-to-date non-thermal processing technology with a wide range of applications in the food industry. The inactivation effect of PEF on Escherichia coli was different under different conditions. The E. coli inactivated number was 1.13 ± 0.01 lg CFU/mL when PEF was treated for 60 min and treated with 0.24 kV/cm. The treatment times were found to be positively correlated with the inactivation effect of PEF, and the number of E. coli was reduced by 3.09 ± 0.01 lg CFU/mL after 100 min of treatment. The inactivation assays showed that E. coli was inactivated at electrical intensity (0.24 kV/cm) within 100 min, providing an effective inactivating outcome for Gram-negative bacteria. The purpose of this work was to investigate the cellular level (morphological destruction, intracellular macromolecule damage, intracellular enzyme inactivation) as well as the molecular level via transcriptome analysis. Field Emission Scanning Electron Microscopy (TFESEM) and Transmission Electron Microscope (TEM) results demonstrated that cell permeability was disrupted after PEF treatment. Entocytes, including proteins and DNA, were markedly reduced after PEF treatment. In addition, the activities of Pyruvate Kinase (PK), Succinate Dehydrogenase (SDH), and Adenosine Triphosphatase (ATPase) were inhibited remarkably for PEF-treated samples. Transcriptome sequencing results showed that differentially expressed genes (DEGs) related to the biosynthesis of the cell membrane, DNA replication and repair, energy metabolism, and mobility were significantly affected. In conclusion, membrane damage, energy metabolism disruption, and other pathways are important mechanisms of PEF's inhibitory effect on E. coli.

A trinuclear Zn (II) schiff base dicyanamide complex attenuates bacterial biofilm formation by ROS generation and membrane damage and exhibits anticancer activity

A trinuclear Zn (II) complex, [(ZnL{N(CN)2})2Zn], termed complex 1 has been synthesized by the reaction of an aqueous solution of sodium dicyanamide to the methanolic solution of Zn (CH3COO)2, 2H2O and corresponding Schiff base (H2L) which is derived from 1:2 condensation of 1, 4 butane diamine with 3-ethoxy salicylaldehyde. Complex 1 is characterized by elemental analysis, IR, UV and Single X-ray diffraction study. Drug resistance is a growing global public health concern that has prompted researchers to look into advanced alternative treatment modalities. In this context, complex 1 has shown promising antibacterial and antibiofilm efficacy against gram-positive Staphylococcus aureus and Methicillin-resistant Staphylococcus aureus strains. Complex 1 attenuated Staphylococcal biofilm formation by reducing several virulence factors including the formation of extracellular polysaccharide matrix, slime, haemolysin, staphyloxanthin, auto-aggregation, cell surface hydrophobicity, and motility. Notably, complex 1 mechanistically potentiated Reactive Oxygen Species (ROS) generation within the bacterial cells, leading to the damage of bacterial cell membrane followed by DNA leakage and thereby impeding the growth of Staphylococcus aureus. Furthermore, complex 1 significantly exhibited anticancer activity by reducing the growth of prostate adenocarcinoma cells. It obstructed the migration of cancer cells by potentiating apoptosis and arresting the cell cycle at the G2/M phase. In summary, complex 1 could act as a potent candidate for the generation of novel antibacterial, antibiofilm as well as anticancer treatment regimens for the management of drug-resistant biofilm-mediated Staphylococcus aureus infection and lethal prostate malignancy.

Bacteriophage-mediated biosynthesis of MnO2NPs and MgONPs and their role in the protection of plants from bacterial pathogens

Introduction

Xanthomonas oryzae pv. oryzae (Xoo) is the plant pathogen of Bacterial Leaf Blight (BLB), which causes yield loss in rice.

Methods

In this study, the lysate of Xoo bacteriophage X3 was used to mediate the bio-synthesis of MgO and MnO₂. The physiochemical features of MgONPs and MnO₂NPs were observed via Ultraviolet - Visible spectroscopy (UV-Vis), X-ray diffraction (XRD), Transmission/Scanning electron microscopy (TEM/SEM), Energy dispersive spectrum (EDS), and Fourier-transform infrared spectrum (FTIR). The impact of nanoparticles on plant growth and bacterial leaf blight disease were evaluated. Chlorophyll fluorescence was used to determine whether the nanoparticles application were toxic to the plants.

Results

An absorption peak of 215 and 230 nm for MgO and MnO₂, respectively, confirmed nanoparticle formation via UV-Vis. The crystalline nature of the nanoparticles was detected by the analysis of XRD. Bacteriological tests indicated that MgONPs and MnO₂NPs sized 12.5 and 9.8 nm, respectively, had strong in vitro antibacterial effects on rice bacterial blight pathogen, Xoo. MnO₂NPs were found to have the most significant antagonist effect on nutrient agar plates, while MgONPs had the most significant impact on bacterial growth in nutrient broth and on cellular efflux. Furthermore, no toxicity to plants was observed for MgONPs and MnO₂NPs, indeed, MgONPs at 200 μg/mL significantly increased the quantum efficiency of PSII photochemistry on the model plant, Arabidopsis, in light (ΦPSII) compared to other interactions. Additionally, significant suppression of BLB was noted in rice seedlings amended with the synthesized MgONPs and MnO₂NPs. MnO₂NPs showed promotion of plant growth in the presence of Xoo compared to MgONPs.

Conclusion

An effective alternative for the biological production of MgONPs and MnO₂NPs was reported, which serves as an effective substitute to control plant bacterial disease with no phytotoxic effect.

Exploring the biological application of Penicillium fimorum-derived silver nanoparticles: In vitro physicochemical, antifungal, biofilm inhibitory, antioxidant, anticoagulant, and thrombolytic performance

This study showed the anti-candida, biofilm inhibitory, antioxidant, anticoagulant, and thrombolytic properties of biogenic silver nanoparticles (AgNPs) fabricated by using the supernatant of Penicillium fimorum (GenBank accession number OQ568180) isolated from soil. The biogenic AgNPs were characterized by using different analytical techniques. A sharp surface plasmon resonance (SPR) peak of the colloidal AgNPs at 429.5 nm in the UV-vis spectrum confirmed the fabrication of nanosized silver particles. The broth microdilution assay confirmed the anti-candida properties of AgNPs with a minimum inhibitory concentration (MIC) of 4 μg mL^-1. In the next step, the protein and DNA leakage assays as well as reactive oxygen species (ROS) assay were performed to evaluate the possible anti-candida mechanisms of AgNPs representing an increase in the total protein and DNA of supernatant along with a climb-up in ROS levels in AgNPs-treated samples. Flow cytometry also confirmed a dose-dependent cell death in the AgNPs-treated samples. Further studies also confirmed the biofilm inhibitory performance of AgNPs against Candia albicans. The AgNPs at the concentrations of MIC and 4*MIC inhibited 79.68 ± 14.38% and 83.57 ± 3.41% of biofilm formation in C. albicans, respectively. Moreover, this study showed that the intrinsic pathway may play a significant role in the anticoagulant properties of AgNPs. In addition, the AgNPs at the concentration of 500 μg mL^-1, represented 49.27%, and 73.96 ± 2.59% thrombolytic and DPPH radical scavenging potential, respectively. Promising biological performance of AgNPs suggests these nanomaterials as a good candidate for biomedical and pharmaceutical applications.

Design, Synthesis and Evaluation of a Series of Zinc(II) Complexes of Anthracene-Affixed Multifunctional Organic Assembly as Potential Antibacterial and Antibiofilm Agents against Methicillin-Resistant Staphylococcus aureus

A novel class of zinc(II)-based metal complexes, i.e., [Zn₂(acdp)(μ-Cl)]·2H₂O (1), [Zn₂(acdp)(μ-NO₃)]·2H₂O (2), and [Zn₂(acdp)(μ-O₂CCF₃)]·2H₂O (3) (Cl^- = chloride; NO₃^- = nitrate; CF₃CO₂^- = trifluoroacetate) of anthracene-affixed multifunctional organic assembly, H₃acdp (H₃acdp = N,N'-bis[anthracene-2-ylmethyl]-N,N'-bis[carboxymethyl]-1,3-diaminopropan-2-ol), have emerged as promising antibacterial and antibiofilm agents in the domain of medicinal chemistry. Accordingly, complexes 1-3 were synthesized by utilizing H₃acdp in combination with ZnCl₂, Zn(NO₃)₂·6H₂O, and Zn(CF₃CO₂)₂·H₂O respectively, in the presence of NaOH at ambient temperature. The complexation between H₃acdp and Zn²⁺ was delineated by a combined approach of spectrophotometric and spectrofluorometric titration studies. The stoichiometry of acdp^3-/Zn²⁺ in all three complexes is observed to be 1:2, as confirmed by spectrophotometric/spectrofluorometric titration data. Elemental analysis (C, H, N, Zn), molar conductance, FTIR, UV-vis, and thermoanalytical (TGA/DTA) data were effectively used to characterize these complexes. Besides, the structures of 1-3 were established by density functional theory (DFT) calculation using B3LYP/6-311G, specifying a self-assembled compact geometry with average Zn···Zn separation of 3.4629 Å. All three zinc complexes exhibited significantly high antibacterial and antibiofilm activity against methicillin-resistant Staphylococcus aureus (MRSA BAA1717). However, complex 1 showed a more recognizable activity than 2 and 3, with minimum inhibitory concentration (MIC) values of 200, 350, and 450 μg/mL, respectively. The antimicrobial activity was tested by employing the minimum inhibitory concentration (MIC) and time-kill assay. The crystal violet (CV) assay and microscopic study were performed to examine the antibiofilm activity. As observed, complexes 1-3 had an effect on the production of extracellular polymeric substance (EPS), biofilm cell-viability, and other virulence factors such as staphyloxanthin and hemolysin production, autoaggregation ability, and microbial cell-surface hydrophobicity. Reactive oxygen species (ROS) generated due to inhibition of staphyloxanthin production in response to 1-3 were also analyzed. Moreover, complexes 1-3 showed an ability to damage the bacterial cell membrane due to accumulation of ROS resulting in DNA leakage. In addition, complexes 1-3 displayed a synergistic/additive activity with a commercially available antibiotic drug, vancomycin, with enhanced antibacterial activity. On the whole, our investigation disclosed that complex 1 could be a promising drug lead and attract much attention to medicinal chemists compared to 2 and 3 from therapeutic aspects.

Perspectives on Usage of Functional Nanomaterials in Antimicrobial Therapy for Antibiotic-Resistant Bacterial Infections

The clinical applications of nanotechnology are emerging as widely popular, particularly as a potential treatment approach for infectious diseases. Diseases associated with multiple drug-resistant organisms (MDROs) are a global concern of morbidity and mortality. The prevalence of infections caused by antibiotic-resistant bacterial strains has increased the urgency associated with researching and developing novel bactericidal medicines or unorthodox methods capable of combating antimicrobial resistance. Nanomaterial-based treatments are promising for treating severe bacterial infections because they bypass antibiotic resistance mechanisms. Nanomaterial-based approaches, especially those that do not rely on small-molecule antimicrobials, display potential since they can bypass drug-resistant bacteria systems. Nanoparticles (NPs) are small enough to pass through the cell membranes of pathogenic bacteria and interfere with essential molecular pathways. They can also target biofilms and eliminate infections that have proven difficult to treat. In this review, we described the antibacterial mechanisms of NPs against bacteria and the parameters involved in targeting established antibiotic resistance and biofilms. Finally, yet importantly, we talked about NPs and the various ways they can be utilized, including as delivery methods, intrinsic antimicrobials, or a mixture.

Bioinspired Green Synthesis of Silver Nanoparticles Using Three Plant Extracts and Their Antibacterial Activity against Rice Bacterial Leaf Blight Pathogen Xanthomonas oryzae pv. oryzae

Rice bacterial leaf blight caused by Xanthomonas oryzae pv. oryzae (Xoo) is responsible for a significant reduction in rice production. Due to the small impact on the environment, biogenic nanomaterials are regarded as a new type of antibacterial agent. In this research, three colloids of silver nanoparticles (AgNPs) were synthesized with different biological materials such as Arctium lappa fruit, Solanum melongena leaves, and Taraxacum mongolicum leaves, and called Al-AgNPs, Sm-AgNPs and Tm-AgNPs, respectively. The appearance of brown colloids and the UV-Visible spectroscopy analysis proved the successful synthesis of the three colloids of AgNPs. Moreover, FTIR and XRD analysis revealed the formation of AgNPs structure. The SEM and TEM analysis indicated that the average diameters of the three synthesized spherical AgNPs were 20.18 nm, 21.00 nm, and 40.08 nm, respectively. The three botanical AgNPs had the strongest bacteriostatic against Xoo strain C2 at 20 μg/mL with the inhibition zone of 16.5 mm, 14.5 mm, and 12.4 mm, while bacterial numbers in a liquid broth (measured by OD600) decreased by 72.10%, 68.19%, and 65.60%, respectively. Results showed that the three AgNPs could inhibit biofilm formation and swarming motility of Xoo. The ultrastructural observation showed that Al-AgNPs adhered to the surface of bacteria and broke the bacteria. Overall, the three synthetic AgNPs could be used to inhibit the pathogen Xoo of rice bacterial leaf blight.

Bio-Hybrid Hydrogels Incorporated into a System of Salicylic Acid-pH/Thermosensitive Nanocarriers Intended for Cutaneous Wound-Healing Processes

In this paper, the preparation method of bio-hybrid hydrogels incorporated into a system of salicylic acid-pH/thermosensitive nanocarriers to speed up the wound-healing process was developed. This combination creates a dual drug delivery system, which releases the model hydrophobic active substance-salicylic acid-in a gradual and controlled manner for an extended time. Our research team has determined the various properties of bio-hybrid hydrogels based on their physicochemical (swelling degree, and degradation), structural (FT-IR), morphological (SEM), and mechanical (elongation tests) traits. Moreover, empty pH/thermosensitive nanocarriers and their salicylic acid-containing systems were characterized using the following methods: DLS, TG/DTG, and DSC. Additionally, salicylic acid release profiles directly from thermosensitive nanocarriers were compared to the bio-hybrid matrix. These studies were conducted in PBS (pH = 7.4) for 7 days using the USP4 method. To evaluate the antibacterial properties of the obtained materials, the inhibition of growth of Staphylococcus aureus, Escherichia coli, Candida albicans, and Aspergillus niger-as the main microorganisms responsible for human infections-were tested. The obtained results indicated that the pH/thermosensitive nanocarrier-salicylic acid system and bio-hybrid hydrogels are characterized by antibacterial activity against both S. aureus and E. coli.

Biosynthesis of silver nanoparticles for the fabrication of non cytotoxic and antibacterial metallic polymer based nanocomposite system

Nanomaterials have significantly contributed in the field of nanomedicine as this subject matter has combined the usefulness of natural macromolecules with organic and inorganic nanomaterials. In this respect, various types of nanocomposites are increasingly being explored in order to discover an effective approach in controlling high morbidity and mortality rate that had triggered by the evolution and emergence of multidrug resistant microorganisms. Current research is focused towards the production of biogenic silver nanoparticles for the fabrication of antimicrobial metallic-polymer-based non-cytotoxic nanocomposite system. An ecofriendly approach was adapted for the production of silver nanoparticles using fungal biomass (Aspergillus fumigatus KIBGE-IB33). The biologically synthesized nanoparticles were further layered with a biodegradable macromolecule (chitosan) to improve and augment the properties of the developed nanocomposite system. Both nanostructures were characterized using different spectrographic analyses including UV–visible and scanning electron microscopy, energy dispersive X-ray analysis, dynamic light scattering, and Fourier transform infrared spectroscopic technique. The biologically mediated approach adapted in this study resulted in the formation of highly dispersed silver nanoparticles that exhibited an average nano size and zeta potential value of 05 nm (77.0%) and − 22.1 mV, respectively with a polydispersity index of 0.4. Correspondingly, fabricated silver–chitosan nanocomposites revealed a size of 941 nm with a zeta potential and polydispersity index of + 63.2 mV and 0.57, respectively. The successful capping of chitosan on silver nanoparticles prevented the agglomeration of nanomaterial and also facilitated the stabilization of the nano system. Both nanoscopic entities exhibited antimicrobial potential against some pathogenic bacterial species but did not displayed any antifungal activity. The lowest minimal inhibitory concentration of nanocomposite system (1.56 µg ml⁻¹) was noticed against Enterococcus faecalis ATCC 29212. Fractional inhibitory concentration index of the developed nanocomposite system confirmed its improved synergistic behavior against various bacterial species with no cytotoxic effect on NIH/3T3 cell lines. Both nanostructures, developed in the present study, could be utilized in the form of nanomedicines or nanocarrier system after some quantifiable trials as both of them are nonhazardous and have substantial antibacterial properties.

Synthesis and characterization of chitosan silver nanoparticle decorated with benzodioxane coupled piperazine as an effective anti-biofilm agent against MRSA: A validation of molecular docking and dynamics

Biomaterial research has improved the delivery and efficacy of drugs over a wide range of pharmaceutical applications. The objective of this study was to synthesize benzodioxane coupled piperazine decorated chitosan silver nanoparticle (Bcp*C@AgNPs) against methicillin-resistant Staphylococcus aureus (MRSA) and to assess the nanoparticle as an effective candidate for antibacterial and anti-biofilm care. Antibacterial activity of the compound was examined and minimum inhibitory concentration (MIC) was observed at (10.21 ± 0.03 ZOI) a concentration of 200 μg/mL. The Bcp*C@AgNPs interferes with surface adherence of MRSA, suggesting an anti-biofilm distinctive property that is verified for the first time by confocal laser microscopic studies. By ADMET studies the absorption, distribution, metabolism, excretion and toxicity of the compound was examined. The interaction solidity and the stability of the compound when surrounded by water molecules were analyzed by docking and dynamic simulation analysis. The myoblast cell line (L6) was considered for toxicity study and was observed that the compound exhibited less toxic effect. This current research highlights the biocidal efficiency of Bcp*C@AgNPs with their bactericidal and anti-biofilm properties over potential interesting clinical trial targets in future.

Antimicrobial activity of biosynthesized silver nanoparticles, amoxicillin, and glass-ionomer cement againstStreptococcus mutansandStaphylococcus aureus

Background. The development of dental caries is associated with various microorganisms and secondary caries formation is the main cause of restorations failure. The advice for restorative dental materials that have antimicrobial properties has stimulated the introduction of materials containing different antibacterial agents.Objectives. The present study has been designed to synthesize silver nanoparticles (AgNPs) and incorporate AgNPs and amoxicillin into glass ionomer cement (GIC) to synergize its effect on oral microbes. The effect of the added antimicrobial agents on compressive strength (CS) of GIC was also evaluated.Material and methods. Biosynthesis of AgNPs was done usingCupressus macrocarpaextract and AgNPs were characterized. A total of 120 disc-shaped specimens were prepared and classified into 4 main groups where Group A includes conventional GIC, Groups B and C include GIC with AgNPs or amoxicillin, respectively, while Group D included GIC with both AgNPs and amoxicillin. Each group was tested for the antimicrobial activity against bothStreptococcus mutans(S. mutans) andStaphylococcus aureus(S. aureus). The distribution of biofilm was examined via a scanning electron microscope. The CS of the tested material was measured using a Material Test System.Results. The UV-visible spectrum showed a peak of 429 nm. Transmission electron microscopy, x-ray diffraction pattern and Fourier transform infrared analysis confirmed the formation of AgNPs with spherical to oblong polydispersed particles of diameter in the range of 13.5-25.8 nm. The maximum inhibitory zone was recorded for group D against both tested bacteria with a mean of 29 mm at first 24 h period to 15 mm at three weeks and showed antimicrobial rate 92.2% and 92.56%, against both strains, respectively. Additionally, group D disintegrated the structure ofS. aureusbiofilm and even kill bacteria in the biofilms. The addition of AgNPs and amoxicillin caused an insignificant effect on CS of GIC.Conclusion.TheAgNPs showed a synergistic effect in combination with amoxicillin and GIC dental restorative material against studied microorganisms. The agents can be safely added with minimal effect on the mechanical properties of the original cement.

Investigation of Ultrasonic Treatment on Physicochemical, Structural and Morphological Properties of Sodium Alginate/AgNPs/Apple Polyphenol Films and Its Preservation Effect on Strawberry

An antibacterial and anti-oxidation composite film was prepared by a casting method using sodium alginate (SA) and apple polyphenols (APPs) as the base material and glycerol as the plasticizer. Silver nanoparticles (AgNPs) were deposited by ultrasonic-assisted electrospray method. The degree of influence of the addition ratio of SA and AgNPs and different ultrasonic time on the mechanical properties, barrier properties, optical properties, and hydrophilicity of the composite film was explored. The composite films were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results showed that the SA: AgNPs ratio of 7:3 and the ultrasonic time for 30 min have the best comprehensive performance, and SA/AgNPs/APP films showed the lowest water vapor permeability value of 0.75 × 10⁻¹¹ g/m·s·Pa. The composite film has good strength and softness, with tensile strength (TS) and elongation at break (E) at 23.94 MPa and 29.18%, respectively. SEM images showed that the surface of the composite film was smooth and the AgNPs’ distribution was uniform. The composite film showed broad antibacterial activity, and the antibacterial activity of Escherichia coli (92.01%) was higher than that of Staphylococcus aureus (91.26%). However, due to the addition of APP, its antioxidant activity can reach 98.39%, which has a synergistic effect on antibacterial activity. For strawberry as a model, the results showed that this composite film can prolong the shelf life of strawberries for about 8 days at 4 °C, effectively maintaining their storage quality. Compared with the commonly used PE(Polyethylene film) film on the market, it has a greater fresh-keeping effect and can be used as an active food packaging material.