Antimicrobial Efficacy Research Articles

Microencapsulation of Anthocyanins from Zea mays and Solanum tuberosum: Impacts on Antioxidant, Antimicrobial, and Cytotoxic Activities

Objectives: This study investigates the biological activities of microencapsulated anthocyanins extracted from two Andean ancestral edible plants, Solanum tuberosum, and Zea mays, with a focus on their potential applications in functional foods and therapeutics. The primary objective was to evaluate their antioxidant, antimicrobial, and cytotoxic properties alongside structural and functional analyses of the microencapsulation process. Methods: Anthocyanins were extracted and microencapsulated using maltodextrin as a carrier. Fourier-transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) were employed to analyze the stability and structure of the microencapsulated particles. The antioxidant, antimicrobial, and cytotoxic activities of the microencapsulated were assessed through established assays. Results:S. tuberosum exhibited superior antioxidant capacity and potent anticancer activity against HepG2 and THJ29T cell lines, while Z. mays demonstrated significant antimicrobial efficacy against multidrug-resistant bacterial strains and biofilm-forming pathogens. Fourier-transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) confirmed the stabilization of anthocyanins within a maltodextrin matrix, enhancing their bioavailability and application potential. Conclusions: These results highlight the versatility of microencapsulated anthocyanins as bioactive agents for industrial and therapeutic applications. Future studies should explore in vivo validation and synergistic formulations to optimize their efficacy and broaden their use in nutraceutical and pharmaceutical fields.

Deciphering physical and functional properties of chitosan-based particles for agriculture applications

Traditional methods for controlling plant pathogens rely on toxic chemicals, posing environmental and health risks. Developing sustainable, eco-friendly alternatives is crucial. Chitosan (CS)-based materials offer promising solutions for sustainable agriculture. We aimed to synthesize and characterize CS-based microparticles with varying properties and assess their antimicrobial performance to establish correlations between variations in physicochemical characteristics and their impact on performance within biological systems. We adjusted the synthesis parameters, producing particles labeled P1, P2, and P3, which have sizes of 0.19 ± 0.07 μm, 0.45 ± 0.32 μm, and 1.22 ± 0.32 μm, and zeta potentials of +7.6 ± 4.25 mV, +22 ± 3.51 mV, and + 12.9 ± 4.54 mV, respectively. Extensive toxicological screenings showed that these CS-based microparticles were non-toxic across cell cultures, mouse red blood cells, soil microbiota, nitrogen-cycling bacteria, and plant toxicity assays. Encouraged by these results, we evaluated their antimicrobial potential against economically important crop pathogens. The CS-based microparticles exhibited antimicrobial effects against the bacterium Pseudomonas syringae pv. tomato DC3000 and the fungus Fusarium solani f. sp. eumartii. Higher zeta potentials correlated with greater antimicrobial efficacy, evidenced by lower IC50 and minimum inhibitory concentration (MIC) values. These findings indicate that all three microparticles analyzed displayed antimicrobial activity against two economically significant crop pathogens, with P2 showing solid performance attributed to its physicochemical characteristics. Therefore, CS-based microparticles represent a promising, nontoxic, and environmentally friendly alternative for modern agriculture, with their biological activities potentially predictable through careful selection of physicochemical properties before the synthesis process.

Effectiveness of sodium hypochlorite and benzalkonium chloride in reducing spoilage yeast biofilms on food contact surfaces

The study evaluates the effectiveness of sodium hypochlorite (NaOCl) and a commercial quaternary ammonium compound (QAC) against planktonic and biofilm-associated yeast (Candida tropicalis, C. krusei, C. kefyr, and Rhodotorula mucilaginosa) isolated from ultrafiltration modules in a clarified apple juice production facility. The results demonstrated that the efficacy of disinfection against planktonic yeast cells did not directly correlate with the effectiveness against biofilm-embedded cells. QAC proved to be more effective than NaOCl in reducing yeast biofilms, achieving a higher than 3-log10 reduction in cell counts. In contrast, NaOCl, even at its maximum permissible concentration for food-contact surfaces, exhibited limited efficacy against biofilms. Both disinfectants had limited success in preventing biofilm regrowth, indicating the potential for persistent contamination in food processing environments. Furthermore, both agents compromised biofilm structure, with QAC having a significantly more pronounced impact than NaOCl.

Exploring the enhanced bioactivity and reactivity of novel Fe(III) and Co(II) complexes incorporating sulfadiazine tetradentate ligand: Structural, DFT, molecular docking, and biological applications

This current work presented the synthesis, characterization and bio-evaluation of new Fe(III) (FePSD), and Co(II) (CoPSD) complexes based on N-[4-amino-5-cyano-6-(methylthio)pyridin-2-yl]-3-oxobutanamide in pyridine afford N-(4-amino-5-cyano-6-(methylthio) pyridin-2-yl)-3-oxo-2-([4-(pyrimidin-2-ylsulfamoyl) phenyl]hydrazono) butanamide (PSD). Interestingly, the FePSD and CoPSD complexes exhibit notable stability and solubility in organic solvents, with molar conductivity values of 79.35 Ω−1 cm2 mol−1 for FePSD and 8.89 Ω−1 cm2 mol−1 for CoPSD, indicating a 1:1 electrolytic nature for FePSD and non-electrolytic behavior for CoPSD. FTIR analysis confirmed metal–ligand interactions, as shifts in key bands were observed, while UV–Vis spectra and magnetic moment measurements supported octahedral geometries for both complexes. DFT calculations provided insights into the electronic structure, revealing that CoPSD has higher reactivity and electrophilicity, while FePSD showed moderate reactivity. Thermal and mass spectral analyses further characterized their stoichiometry and stability. The antibacterial and antifungal activities were evaluated against a range of Gram-positive and Gram-negative bacteria and fungal strains. The FePSD and CoPSD complexes demonstrated significantly enhanced antimicrobial efficacy compared to the parent ligand, as evidenced by larger inhibition zones, higher activity indices, and lower minimum inhibition concentrations (MIC). CoPSD exhibited superior antibacterial and antifungal activity compared to FePSD, nearing the effectiveness of standard antibiotics and antifungal drugs. Additionally, the anti-inflammatory potential of these compounds was assessed using the egg albumin denaturation method. Both FePSD and CoPSD showed remarkable inhibition of protein denaturation, surpassing the parent ligand and even outperforming the standard drug Ibuprofen at higher concentrations. The enhancement in biological activity is attributed to the metal chelation effect, which improves cell membrane permeability and reactive oxygen species (ROS) generation. Molecular docking studies further elucidated the binding interactions of PSD, FePSD, and CoPSD with target proteins, revealing stronger hydrophobic interactions and hydrogen bonding in the metal complexes, correlating with their superior biological activity. These findings highlight the potential of FePSD and CoPSD as promising antimicrobial and anti-inflammatory agents.

Recombinant Production of Ib-AMP4 and Oncorhyncin II Antimicrobial Peptides and Antimicrobial Synergistic Assessment on the Treatment of Staphylococcus aureus Under in vitro Condition.

Methicillin-resistant Staphylococcus aureus (MRSA) is a significant and prevalent pathogen that poses a major challenge in healthcare environments. In light of the growing threat posed by multidrug-resistant organisms like MRSA, there is an urgent need for alternative therapeutic strategies. One promising avenue of research involves the use of antimicrobial peptides (AMPs). These naturally occurring molecules, which are part of the innate immune response in many organisms, have garnered attention for their ability to combat a wide range of pathogens. This study aimed to produce recombinant versions of Ib-AMP4 and Oncorhyncin II and to evaluate their combined effects against MRSA (NCTC10442). Escherichia coli BL21(DE3] served as the expression host for the synthesized variants of the Ib-AMP4 and Oncorhyncin II genes. The antimicrobial efficacy of these peptides against MRSA S. aureus (NCTC1042] was evaluated using a comprehensive methodology that encompassed the determination of the minimum inhibitory concentration (MIC), the performance of time-kill assays, and the analysis of growth kinetics. The individual antimicrobial activities of Ib-AMP4 and Oncorhyncin II were assessed, revealing minimum inhibitory concentrations (MICs) of 27.75 μg/mL and 40.125 μg/mL against S. aureus (MRSA) (NCTC10442), respectively. The application of a checkerboard assay to evaluate the combination of these antimicrobial peptides (AMPs) demonstrated a synergistic interaction, which was further validated through time-kill and growth kinetic studies. When administered at double the MIC, a significant reduction in the log10 CFU/mL of MRSA (NCTC 10442) was observed, underscoring the synergistic bacteriostatic effect mediated by the fractional inhibitory concentration (FIC) index of the two peptides. Antimicrobial peptides (AMPs) have attracted significant interest owing to the growing intricacy of microbial infections. They constitute a promising category of novel antibiotics that warrant further investigation for the treatment of S. aureus infections and the enhancement of wound healing. Although certain AMPs can operate autonomously, others may necessitate a synergistic approach alongside conventional antibiotics. Studies examining the combined efficacy of Oncorhyncin II and Ib-AMP4 against MRSA in vitro have revealed their effectiveness.

Evolution of copper resistance in Xanthomonas euvesicatoria pv. perforans population.

The widespread use of antimicrobials that target bacterial pathogens has driven evolution of resistance, compromising the efficacy of these bactericides. Understanding the emergence and spread of resistance genes via mobile genetic elements is crucial for combating antimicrobial resistance. Copper resistance (CuR) in Xanthomonas euvesicatoria pv. perforans has severely affected the efficacy of copper-based bactericides for controlling bacterial leaf spot disease of tomato and pepper. Here, we investigated the evolutionary pathways of CuR acquisition and dissemination in X. euvesicatoria pv. perforans using an extensive collection of strains. We determined that chromosomally encoded CuR predominates over plasmid-borne CuR in multiple distinct phylogenetic groups of X. euvesicatoria pv. perforans. Our analysis revealed a single site of chromosomal integration by a CuR genomic island, although the genomic island showed sequence variation among phylogenetic groups. While chromosomal CuR was more prevalent, strains with plasmid-borne resistance conferred greater copper tolerance. Additionally, we identified strains carrying two copies of CuR genes, on plasmid and chromosome, that exhibited increased copper tolerance. Strains of X. euvesicatoria pv. perforans from the USA shared identical CuR gene sequences whether on plasmids or chromosome while different alleles were found in strains from other countries. In contrast to X. euvesicatoria pv. perforans, plasmid-borne CuR predominated in closely related pathovar, X. euvesicatoria pv. euvesicatoria. Overall, these findings contribute to a better understanding of the evolution and persistence of CuR in X. euvesicatoria pv. perforans and its closest relatives.IMPORTANCEThe emergence of antimicrobial resistance is a significant threat to agricultural production as it reduces the efficacy of various antimicrobials including copper-based bactericides that are widely used to control plant diseases. The challenge of increasing antimicrobial resistance entering a production system necessitates a deeper understanding of the dynamics and mechanisms by which pathogens acquire resistance. As a result of this research, we have identified different mechanisms of copper resistance acquisition as well as levels of copper resistance in a devastating plant pathogen, X. euvesicatoria pv. perforans. The evolution and dissemination of copper resistance in strains through plasmid or chromosomally integrated genomic island or both presents barriers to current management approaches, where growers rely heavily on copper-based bactericides to manage disease outbreaks. This knowledge is crucial when considering the continued use of existing antimicrobials or adopting alternative antimicrobials in efforts to implement enhanced antimicrobial stewardship strategies in agriculture.

Efficacy of photoClO2 against two human norovirus surrogates and Clostridioides difficile endospores on stainless steel and nylon carpet.

Determine efficacy of an aqueous photocatalytic disinfection system, photoClO2, against two human norovirus surrogates [feline calicivirus (FCV) and Tulane virus (TuV)] and Clostridioides difficile endospores on stainless steel and nylon carpet. The photoClO2 system was first optimized with 1% sodium chlorite (NaClO2) and 10 ppm Eosin Y to produce 60.64 ppm ClO2/min in a 4.5×4.5 cm2 area. It was then tested against FCV, TuV, and C. difficile endospores on stainless steel and nylon carpet with two different backings. On stainless steel, photoClO2 achieved a >5 log10 plaque-forming unit (PFU) reduction of FCV in 45 min, >3 log10 median tissue culture infectious dose (TCID50) reduction of TuV in 60 min, and 1.3 log10 colony-forming unit (CFU) reduction of C. difficile endospores in 120 min. Under indoor lighting conditions, photoClO2 achieved a 4.3 log10 PFU reduction of FCV and 1.4 log10 TCID50 reduction of TuV on stainless steel after 120 min. Further, photoClO2 achieved a 2.9 log10 PFU reduction of FCV and 2.5 log10 TCID50 reduction of TuV on nylon carpet with waterproof backing in 60 min, which was higher than carpet with water-permeable backing (1.3 log10 PFU and 1.1 log10 TCID50 reduction, respectively). ClO2 production rate of the photoClO2 system was influenced by light distribution, while disinfection efficacy was affected by light intensity, surface characteristics, and target microorganisms. PhotoClO2 was efficacious in inactivating both human norovirus surrogates on stainless steel and nylon carpet. Efficacy against C. difficile endospores was limited.

Collagen and chitosan-based biogenic sprayable gel of silver nanoparticle for advanced wound care.

Silver nanoparticles have gained significant attention recently due to their unique antibacterial properties, making them promising candidates for wound care applications. This study proposes a novel approach for advanced wound care using a silver nanoparticle-impregnated biogenic spray hydrogel supplemented with collagen and chitosan. Silver nanoparticles were incorporated into the hydrogel (optimized by a QbD approach) to impart antimicrobial activity, crucial for combating wound infections and promoting faster healing. The study assessed the physical and chemical properties of the biogenic hydrogel, including its viscosity, pH, and nanoparticle dispersion characteristics. In vitro, antimicrobial efficacy against common wound pathogens and in vivo studies using chronic wound models in small animals portrayed the immense potential of the developed biogenic hydrogel in effectively reducing the bacterial load of broad-spectrum pathogens. The hydrogel exhibited excellent biocompatibility, supporting cell proliferation and tissue repair without toxic effects. It accelerated wound healing, improved collagen deposition, and enhanced tissue regeneration in the tested animals by reducing proinflammatory cytokines, ROS, and NF-kb levels. Overall, this innovative silver nanoparticle-impregnated biogenic spray hydrogel of collagen and chitosan presents a uniform spray pattern that proved efficient, showing a promising solution for advanced wound care. Its biocompatibility, safety, anti-inflammatory, antimicrobial efficacy, and wound healing properties hold great potential for improving the management of complex wounds, opening new avenues in wound care and regenerative medicine.

Experimental confirmation of the bactericidal action of the domestic antiseptic “Anolit” in surgical practice

Background. Antimicrobial resistance is one of the most serious threats to modern clinical medicine. Despite the significant successes of modern pharmacology, the search for effective antiseptics that can influence wound processes continues. In our study, an experimental study of the effect of Anolit solution on pathogenic microorganisms Pseudomonas aeruginosa and Proteus mirabilis was conducted.The aim. To evaluate the antimicrobial activity of the domestic antiseptic “Anolit” against gram-negative pathogens of nosocomial infections using the example of P. aeruginosa and P. mirabilis.Methods. To assess the quality of the effect of “Anolit” on the studied colonies of microorganisms, experimental studies were performed in vitro. The bacteriological study was carried out in three stages using the Koch method.Results. “Anolit” is a modern antiseptic agent with a pronounced antimicrobial effect based on the electrolysis of aqueous solutions. Its ability to lyse pathogenic microorganisms (P. aeruginosa and P. mirabilis) has been confirmed by experimental research.Conclusion. The bactericidal effect of “Anolit” on the growth of gram-negative bacteria is shown, proving its high antimicrobial efficacy.

Investigation of the mechanical properties of lavender-reinforced heat-activated polymethyl methacrylate denture base resin

Statement of problemThe antimicrobial efficacy of lavender has been well evidenced. However, investigations into its impact on the mechanical properties of denture resins are lacking. PurposeThe purpose of this in vitro study was to evaluate the flexural strength, impact strength, surface characteristics, roughness, elastic modulus, and yield strength of lavender-reinforced, heat-activated polymethyl methacrylate denture base resin. Material and methodsA total of 200 specimens were categorized into 5 groups based on 0, 0.5, 1.0, 1.5, and 2.0 wt% of dry lavender extract incorporated into heat-activated polymethyl methacrylate denture base resin powder. Unmodified resin served as the control group. Flexural strength, elastic moduli, and yield strength were determined with a universal testing machine, impact strength with an Izod impact tester, surface characteristics with scanning electron microscopy, and roughness with a profilometer. The data were statistically analyzed with 1-way ANOVA followed by Tukey post hoc tests for pairwise comparison within the groups (α=.05). ResultsCompared with the control group, all the mechanical properties significantly improved with the addition of lavender (P<.001). The highest flexural, yield, and impact strengths and elastic modulus values were in the 2% group. Elevated surface roughness in 0.5, 1.0 and 1.5 wt% and a decline in roughness at 2 wt% were noted when compared with the control group. ConclusionsThe addition of lavender enhanced the flexural strength, yield strength, impact strength, elastic moduli, and decreased surface roughness when added at 2 wt%.

Improving Antimicrobial Properties of Biopolymer-Based Films in Food Packaging: Key Factors and Their Impact

Biodegradable films derived from polysaccharides are increasingly considered eco-friendly alternatives to synthetic packaging in the food industry. The study’s purpose was to improve the antimicrobial properties of biopolymer-based films made from starch, chitosan, alginate, and their blends (starch/chitosan and starch/alginate) and to evaluate the effects of modifiers, i.e., plant extracts, plasticizers, cross-linking agents, and nanofillers. Films were prepared via the Solution Casting Method and modified with various plasticizers, calcium chloride, oxidized sucrose, and nanofiber cellulose (NC). Chestnut, nettle, grape, and graviola extracts were tested for antimicrobial activity against Staphylococcus epidermidis, Escherichia coli, and Candida albicans. The film’s mechanical and hydrophilic properties were studied as well. The chestnut extract showed the strongest antimicrobial properties, leading to its incorporation in all the films. The chitosan films displayed better antibacterial activity against Gram-positive than Gram-negative bacteria but were ineffective against C. albicans. NC significantly improved the mechanical and antimicrobial properties of the chitosan films. The alginate films, modified with various plasticizers cross-linked with calcium chloride, demonstrated the highest antimicrobial efficacy against E. coli. The starch films, cross-linked with oxidized sucrose, exhibited slightly lower antimicrobial resistance due to a more compact structure. Films such as ALG6 and ALG5, including plasticizers EPGOS and PGOS, respectively, indicated optimal hydrophilicity and mechanical properties and achieved the best antimicrobial performance against all the investigated microorganisms. All these findings highlight the potential of these biodegradable films for food packaging, offering enhanced antimicrobial activity that prolongs shelf life and reduces spoilage, making them promising candidates for sustainable food preservation.

Optimizing Ultrasound Probe Disinfection for Healthcare-Associated Infection Control: A Comparative Analysis of Disinfectant Efficacy

Optimizing Ultrasound Probe Disinfection for Healthcare-Associated Infection Control: A Comparative Analysis of Disinfectant Efficacy

Comprehensive evaluation of UV inactivation of E. coli using multiple gene targets and real-time quantitative PCR

UV disinfection is extensively used for wastewater disinfection and disinfection efficiency is commonly monitored using culture-based enumeration of E. coli. While culture-independent real-time quantitative polymerase chain reaction (qPCR) based methods are attractive due to faster turnaround and easier application, previous attempts with qPCR to monitor disinfection have been unsuccessful. In this study, the effect of UV irradiation on a pure E. coli culture was examined in collimated beam (CB) experiments and monitored using both a culturing technique and DNA damage quantified using both short amplicon (SA; <∼200 bp) qPCR and longer amplicon (LA; ∼500-bp) qPCR. The results, covering a UV dose range of 0 - 20 mJ/cm2 commonly used for wastewater disinfection, indicate a correlation between DNA gene damage quantified by both SA- and LA-qPCR and the decline in E. coli observed through culture-based methods. This demonstrates the potential of qPCR to serve as rapid alternative for monitoring wastewater disinfection efficacy. Furthermore, LA-qPCR was observed to be more sensitive than SA-qPCR. The results using LA-qPCR also revealed that UV exposure caused widespread and indiscriminate damage to E. coli’s genome, which is considered critical for its function and survival. The combined effect of UV on E. coli’s ability to function, grow or repair damage is suggested as the reason for the decline in culturability observed.

Insights into an indolicidin-derived low-toxic anti-microbial peptide's efficacy against bacterial cells while preserving eukaryotic cell viability.

Antimicrobial peptides (AMPs) are a current solution to combat antibiotic resistance, but they have limitations, including their expensive production process and the induction of cytotoxic effects. We have developed novel AMP candidate (peptide 3.1) based on indolicidin, among the shortest naturally occurring AMP. The antimicrobial activity of this peptide is demonstrated by the minimum inhibitory concentration, while the hemolysis tests and MTT assay indicate its low cytotoxicity. In optical diffraction tomography, red blood cells treated with peptide 3.1 showed no discernible effects, in contrast to indolicidin. However, peptide 3.1 did induce cell lysis in E. coli, leading to a reduced potential for the development of antibiotic resistance. To investigate the mechanism underlying membrane selectivity, the structure of peptide 3.1 was analyzed using nuclear magnetic resonance spectroscopy and molecular dynamics simulations. Peptide 3.1 is structured with an increased distinction between hydrophobic and charged residues and remained in close proximity to the eukaryotic membrane. On the other hand, peptide 3.1 exhibited a disordered conformation when approaching the prokaryotic membrane, similar to indolicidin, leading to its penetration into the membrane. Consequently, it appears that the amphipathicity and structural rigidity of peptide 3.1 contribute to its membrane selectivity. In conclusion, this study may lead to the development of Peptide 3.1, a promising commercial candidate based on its low cost to produce and low cytotoxicity. We have also shed light on the mechanism of action of AMP, which exhibits selective toxicity to bacteria while not damaging eukaryotic cells.

Introduction to Pharmaceutical Microbiology

Pharmaceutical microbiology is a specialized discipline within pharmaceutical sciences that looks at microorganisms and their impact on drugs, manufacturing methods, and the environment. Microorganisms, inclusive of microorganisms, fungi, viruses, and parasites, can drastically affect the protection, efficacy, and best of pharmaceutical products.with knowledge of their characteristics, interactions, and management measures is crucial to ensuring the safety and effectiveness of medicinal drugs.the field covers diverse components along with infection manipulation, sterility trying out, microbial identification, antimicrobial efficacy testing, and environmental monitoring. One of the main challenges in pharmaceutical microbiology is stopping microbial infection at some stage in the manufacturing process, as even minimum microbial presence can compromise the quality of drug Product and pose risk to the affected person's health. Sterility testing is an important aspect of pharmaceutical microbiology, making sure that sterile products are loose from feasible microorganisms. additionally, microbial identity strategies are used to locate and become aware of microorganisms in pharmaceutical production environments. Pharmaceutical microbiologists play a vital role in the development and testing of antimicrobial agents including antibiotics and antifungals,in the fight in against to microbial contemination. moreover, environmental tracking programs are carried out to assess and manage microbial infection in production centers, making sure compliance with regulatory standards and guidelines. In conclusion, pharmaceutical microbiology is essential for ensuring the protection, efficacy, and first-rate of pharmaceutical products. by knowledge and handling microbial dangers, pharmaceutical microbiologists assist supply secure medications that help public health globally.

The role of secondary structures of peptide polymers on antimicrobial efficacy and antibiotic potentiation.

The rise of antibiotic resistance, biofilm formation, and dormant bacterial populations poses serious global health threats. Synthetic antimicrobial peptide (AMP) mimics offer promising alternatives, though the impact of secondary structures in polymeric AMP mimics on antimicrobial efficacy is underexplored. This study investigates chirality-controlled α-peptide polymers (D-PP and DL-PP), synthesized via ring-opening polymerization of allylglycine N -carboxy anhydrides and post-polymerization modification through thiol-ene click chemistry. D-PP adopts a stable helical structure under biomimetic conditions, whereas DL-PP remains random. This helical structure enhanced D-PP's antibacterial and antibiotic potentiation activities, amplifying antibiotic efficacy by 2- to 256-fold across various classes-including tetracyclines, ansamycins, fusidanes, macrolides, cephalosporins, and monobactams-against multidrug-resistant Gram-negative pathogens, while maintaining low hemolytic activity and high protease stability. Mechanistic investigations revealed that D-PP exhibited greater membrane interaction. D-PP and antibiotic combinations eradicated dormant bacterial populations and disrupted biofilms with minimal antimicrobial resistance development. This study paves the way for the rational design of polypeptide-based antimicrobial agents, harnessing chirality and secondary structural features to enhance the efficacy of synthetic antimicrobial peptide mimics.

Enhancing Antimicrobial Activity of Thyme Essential Oil Through Cellulose Nano Crystals-Stabilized Pickering Emulsions.

Essential oils (EOs), such as thyme essential oil (TEO), are widely known for their antimicrobial properties; however, their direct application in food systems is limited due to their poor stability, which affects their efficacy. This study aims to improve the stability and antimicrobial efficacy of TEO by encapsulating it in Pickering emulsions stabilized with cellulose nanocrystals (CNC). Two formulations of Pickering emulsions with 5% and 10% TEO were prepared and compared to traditional surfactant-based emulsions. The stability of the emulsions was assessed over 21 days, and particle size, zeta potential, Raman spectroscopy, and FTIR were used for characterization. The antimicrobial activity was tested against several foodborne pathogens, with minimum inhibitory concentration (MIC) values determined. The 10% TEO Pickering emulsion showed antimicrobial activity, with MIC50 values of 4096 µg/mL against Staphylococcus aureus and Escherichia coli, while the 5% TEO formulation had no effect at MIC50 > 8192 µg/mL. The CNC-stabilized Pickering emulsions exhibited superior stability, showing no phase separation over 21 days. The findings suggest that CNC-stabilized Pickering emulsions are effective at improving the stability and antimicrobial performance of TEO, making them a promising natural preservative for food packaging and safety. Further research is recommended to optimize the formulation and broaden TEO's application in food preservation.

Assessment of the Antimicrobial Efficacy and Mechanical Properties of Glass Ionomer Cement (GIC) Incorporating Silver Nanoparticles In Varying Concentrations for Pediatric Dental Applications

ABSTRACT Background: Glass ionomer cement (GIC) is widely used in pediatric dentistry due to its fluoride-releasing properties and strong adhesion to tooth structure. However, enhancing its antimicrobial efficacy remains a challenge. Incorporating silver nanoparticles (AgNPs) has been proposed as a solution to increase the antimicrobial properties of GIC without compromising its mechanical strength. Materials and Methods: This study investigated the effects of integrating varying concentrations of AgNPs into GIC on its antimicrobial efficacy against common oral pathogens and its mechanical properties. Three concentrations of AgNPs (0.5%, 1%, and 1.5% by weight) were evaluated. Antimicrobial activity was assessed using the agar diffusion test against Streptococcus mutans and Lactobacillus acidophilus. Mechanical properties, including compressive strength and wear resistance, were measured using standardized tests. Thirty pediatric patients were randomly assigned to receive dental treatments using one of the three modified GIC formulations. Results: The GIC modified with 1% AgNPs demonstrated optimal antimicrobial activity, showing a significant inhibition zone increase of 25% against S. mutans and 20% against L. acidophilus compared to the control. The compressive strength of the GIC was maintained, with the 1% AgNP formulation achieving a compressive strength of 220 MPa, comparable to the control (215 MPa). Wear resistance slightly decreased as the concentration of AgNPs increased. Conclusion: The addition of 1% AgNPs to GIC significantly enhances its antimicrobial properties without adversely affecting its mechanical strength. This formulation holds potential for improving the effectiveness of pediatric dental restorations by reducing the risk of secondary caries.

The novel peptide adjuvants potentiate antimicrobial properties of melittin against methicillin-resistant Staphylococcus aureus and their efficacy as potential food preservatives

Melittin, a notable antimicrobial peptide (AMP), shows great potential in food preservation due to its robust antimicrobial properties, especially when facing multidrug-resistant (MDR) bacteria. However, developing melittin as a food preservative is limited by its poor cell selectively, necessitating innovative strategies are needed to address the application bottleneck of melittin. Here, we characterize two linear peptide adjuvants (3-WP and 9-RP), which exhibited obvious synergistic effects with melittin against common Gram-positive bacteria. Their synergistic effects potentiated antimicrobial efficacy of melittin against methicillin-resistant Staphylococcus aureus (MRSA), while reduced the required dose of melittin for antimicrobial activity, which is contributed to improving the cell selectively of melittin. Mechanistically, 3-WP disrupted cell wall membrane permeability, induced reactive oxygen species (ROS) production, and inhibited energy metabolism. The 3-WP/melittin combination exhibited favorable antimicrobial effects in food storage contexts. Our findings highlighted the great potential of 3-WP as a peptide adjuvant of melittin for combating MDR-associated foodborne diseases and developing safe and effective peptide-based bio-preservatives.

Magnesium-Doped Hydroxyapatite Nanofibers for Medicine Applications: Characterization, Antimicrobial Activity, and Cytotoxicity Study.

Magnesium-doped hydroxyapatite (HAp-Mg) nanofibers show promise for medical applications due to their structural similarity to bone minerals and enhanced biological properties, such as improved biocompatibility and antimicrobial activity. This study synthesized HAp-Mg nanofibers using a microwave-assisted hydrothermal method (MAHM) to evaluate their cytotoxicity, biocompatibility, and antimicrobial efficacy compared to commercial hydroxyapatite (HAp). Characterization through X-ray diffraction (XRD), scanning electron microscopy (SEM), Transmission Electron Microscopy (TEM), energy-dispersive X-ray spectroscopy (EDS), and Fourier transform infrared spectroscopy (FTIR) confirmed the successful incorporation of magnesium, producing high-purity, crystalline nanofibers with hexagonal morphology. Rietveld refinement showed slight lattice parameter shortening, indicating Mg2+ ion integration. Cell viability assays (MTT and AlamarBlue) revealed a significant increase in fibroblast proliferation with 2% and 5% HAp-Mg concentrations compared to controls (p < 0.05), demonstrating non-cytotoxicity and enhanced biocompatibility. Antimicrobial tests (disk diffusion method, 100 µg/mL) showed that HAp-Mg had strong antibacterial effects against Gram-positive and Gram-negative bacteria and moderate antifungal activity against Candida albicans. In contrast, commercial HAp showed no antimicrobial effects. These results suggest HAp-Mg nanofibers have significant advantages as biomaterials for medical applications, particularly in preventing implant-related infections and supporting further clinical development.