Zeta Potential Values Research Articles

A new galactomannan extracted from the seeds of Astragalus gombiformis Pomel (Fabaceae) and its utilization in the biosynthesis of silver nanoparticles

Finding novel sources of polysaccharides with suitable properties for desired uses in numerous sectors, such as nanotechnology, is becoming a more active area of research. Galactomannan (AGFPG) from the seeds of Astragalus gombiformis Pomel (Fabaceae) was extracted and characterized, and its potential application in the biosynthesis of silver nanoparticles (AgNPs) was investigated. The yield after hot water extraction was 10.4% (w/w), and the total carbohydrate content was 83.09 ± 0.03% (w/w). High-performance liquid chromatography and nuclear magnetic resonance revealed that AGFPG was composed of β-D-mannose (60.05%) and α-D-galactose (39.95%), with a Man/Gal ratio of 1.51. Biosynthesis was confirmed by the absorption peak of AgNPs at 423 nm. Scanning electron microscopy images and X-ray diffractogram revealed the spherical shape and the crystalline structure of AgNPs. A Zeta potential value of AgNPs − 48.6 mV showed their high stability. The hydrodynamic diameter of AgNPs by Dynamic light scattering is 144.4 nm. The AgNPs showed significant antimicrobial activity and antioxidant activity (DPPH and Ferric reducing power). AGFPG, as a new galactomannan, can be used as a reducing and capping agent. Biosynthesized AgNPs exhibit good antimicrobial and antioxidant activities, which has led to their use in a variety of fields.

Nanoengineering of novel MXene (Ti3C2Tx) based MgCr2O4 nanocomposite with detailed synthesis, morphology and characterization for enhanced energy storage application

In this study, we presented a novel approach involving the co-precipitation synthesis of a two-dimensional MXene nanocomposite with spinel magnesiochromite MgCr2O4. The resulting nanocomposite was comprehensively characterized. The synthesized nanomaterial exhibited an average crystallite size of approximately 6.85 nm, and its surface morphology confirmed the presence of agglomerated grains with the elemental composition being confirmed by EDS spectra. Raman spectra provided evidence of prominent molecular vibrations, while photoluminescence spectroscopy revealed significant electron-hole recombination within the nanocomposite, leading to a reduced bandgap as corroborated by UV–Vis spectra. Zeta potential measurements shows minimum value of −19.9 mV comparable to MXene zeta potential value –23 mV indicating maximum stability. Electrochemical impedance spectroscopy (EIS) spectra highlighted a minimal charge-transfer resistance value of 64.99 Ω in a basic electrolyte, resulting electron transfer rate value about 4.097 × 10−9 (S/cm) resulting maximum conduction. Electrode capacitive behavior in both acidic (0.1 M H2SO4) and basic media (1 M KOH) demonstrates the potential of this novel nanocomposite material with the maximum capacitance value of 542.6F/g observed in basic media in comparison to the minimum capacitance value of 454.1F/g in acidic media. From GCD analysis, maximum power density of 271.2 kW/kg with an energy density value of 14.58 kWh/kg is achieved. These findings underscore its applicability in energy storage applications partially in the context of supercapacitors.

Solid Lipid Nanoparticles Containing Dopamine and Grape Seed Extract: Freeze-Drying with Cryoprotection as a Formulation Strategy to Achieve Nasal Powders

(1) Background: DA-Gelucire® 50/13-based solid lipid nanoparticles (SLNs) administering the neurotransmitter dopamine (DA) and the antioxidant grape-seed-derived proanthocyanidins (grape seed extract, GSE) have been prepared by us in view of a possible application for Parkinson’s disease (PD) treatment. To develop powders constituted by such SLNs for nasal administration, herein, two different agents, namely sucrose and methyl-β-cyclodextrin (Me-β-CD), were evaluated as cryoprotectants. (2) Methods: SLNs were prepared following the melt homogenization method, and their physicochemical features were investigated by Raman spectroscopy, Scanning Electron Microscopy (SEM), atomic force microscopy (AFM) and X-ray Photoelectron Spectroscopy (XPS). (3) Results: SLN size and zeta potential values changed according to the type of cryoprotectant and the morphological features investigated by SEM showed that the SLN samples after lyophilization appear as folded sheets with rough surfaces. On the other hand, the AFM visualization of the SLNs showed that their morphology consists of round-shaped particles before and after freeze-drying. XPS showed that when sucrose or Me-β-CD were not detected on the surface (because they were not allocated on the surface or completely absent in the formulation), then a DA surfacing was observed. In vitro release studies in Simulated Nasal Fluid evidenced that DA release, but not the GSE one, occurred from all the cryoprotected formulations. Finally, sucrose increased the physical stability of SLNs better than Me-β-CD, whereas RPMI 2650 cell viability was unaffected by SLN-sucrose and slightly reduced by SLN-Me-β-CD. (4) Conclusions: Sucrose can be considered a promising excipient, eliciting cryoprotection of the investigated SLNs, leading to a powder nasal pharmaceutical dosage form suitable to be handled by PD patients.

Synthesis of hydroxyethylcellulose phthalate-modified silver nanoparticles and their multifunctional applications as an efficient antibacterial, photocatalytic and mercury-selective sensing agent

Water contamination by several aquatic pollutants such as dyes, heavy metal ions and microbes is a prevalent concern to health and environment. Thus, developing facile, economical, and eco-friendly strategies to tackle this problem have become paramount. Hence, this study reports the synthesis of hydroxyethylcellulose phthalate-capped silver nanoparticles (HEC-PA@AgNPs) using a simple sunlight-assisted route. The multifunctional applications of the synthesized particles as an efficient nanoprobe for the selective sensing of Hg2+ as well as their photocatalytic and antimicrobial activities were demonstrated. HEC-PA@AgNPs were systematically characterized by various advanced analytical techniques such as FTIR, UV–Vis spectroscopy, X-ray diffraction (XRD), zeta potential (ZP) and dynamic light scattering (DLS). The successful functionalization of AgNPs with HEC-PA was manifested using FTIR. SEM and XRD revealed the formation of spherical AgNPs with a face centered cubic structure and a crystallite size of 14 nm. The particles demonstrated a hydrodynamic size of 40 nm with a good colloidal stability as evidenced from the ZP value of −35 mV, suggesting the effective role of the negatively charged HEC-PA capping agent in stabilizing the NPs. HEC-PA@AgNPs exhibited fast naked-eye colorimetric detection, high selectivity, and sensitivity to Hg2+ in spiked real water samples over a wide range of pH (3–9) and temperatures (298–328 K), achieving a detection limit of 119 nM. The presence of other diverse metal ions didn't affect the specificity of the particles toward Hg ions. Further, the sensing mechanism is based on a characteristic redox reaction between Hg2+ and AgNPs. Further, HEC-PA@AgNPs showcased a more noxious antimicrobial activity to gram-positive bacteria (B. subtilis and S. aureus) than gram-negative bacteria (E. coli). Besides, AgNPs exhibited high photocatalytic potential under sunlight irradiation with a degradation efficiency of 79 % for methylene blue dye in only 80 min following pseudo-1st order kinetics with a rate constant of 0.019 min−1. The photocatalyst exhibited good reusability after five recycling runs. These results render our approach promising multifunctional analytical probe for environmental and biomedical applications.

Optimization of cationic nanoparticles stabilized by poloxamer 188: A potential approach for improving the biological activity of Aloeperryi

Aloe perryi (AP) has gained considerable interest as a medicinal herb in various biological applications due to its rich phytochemical composition. However, the therapeutic benefits of AP could be potentiated by utilizing nanotechnology. Moreover, cationic solid lipid nanoparticles (CSLNs) possess remarkable characteristics that can greatly enrich a variety of biological uses. An optimization approach was used to achieve high-quality CSLNs to maximize the therapeutic efficacy of AP. Therefore, a factorial design was used to investigate the influence of various variables on the attributes of CSLNs quality. In this study, the factors under investigation were compritol 888 ATO (C-888, X1), poloxamer 188 (PL188, X2), and chitosan (CS, X3), which served as independent variables. The parameters measured as dependent variables included particle size (Y1), zeta potential (Y2), and encapsulation efficiency EE (Y3). The relationship among these variables was determined by Analysis of Variance (ANOVA) and response surface plots. The results revealed that PL188 played a significant role in reducing the particle size of CSLNS (ranging from 207 to 261 nm with 1 % PL188 to 167–229 nm with 3 % PL188). Conversely, an increase in the concentration of CS led to a rise in the particle size. The magnitude of positive zeta potential values was dependent on the increased concentration of CS. Moreover, the higher amounts of C-888 and PL188 improved the EE% of the CSLNs from 42 % to 86 %. Furthermore, a concentration-dependent antioxidant effect of the optimized AP-CSLNs was observed. The antioxidant activity of the optimized AP-CSLNs at 100 μg/mL was 75 % compared to 62 % and 60 % for AP-SLNs and AP solution, respectively. A similar pattern of improvement was also observed with antimicrobial, and anticancer activities of the optimized AP-CSLNs. These findings demonstrated the potential of AP-CSLNs as a carrier system, enhancing the biological activities of AP, opening new possibilities in herbal medicines.

Niosomal formulation of mefenamic acid for enhanced cancer targeting; preparation, characterization and biodistribution study using radiolabeling technique

BackgroundThis work aimed to prepare niosomal formulations of an anticancer agent [mefenamic acid (MEF)] to enhance its cancer targeting. 131I was utilized as a radiolabeling isotope to study the radio-kinetics of MEF niosomes.Methodsniosomal formulations were prepared by the ether injection method and assessed for entrapment efficiency (EE%), zeta potential (ZP), polydispersity index (PDI) and particle size (PS). MEF was labeled with 131I by direct electrophilic substitution reaction through optimization of radiolabeling-related parameters. In the radio-kinetic study, the optimal 131I-MEF niosomal formula was administered intravenously (I.V.) to solid tumor-bearing mice and compared to I.V. 131I-MEF solution as a control.Resultsthe average PS and ZP values of the optimal formulation were 247.23 ± 2.32 nm and − 28.3 ± 1.21, respectively. The highest 131I-MEF labeling yield was 98.7 ± 0.8%. The biodistribution study revealed that the highest tumor uptake of 131I-MEF niosomal formula and 131I-MEF solution at 60 min post-injection were 2.73 and 1.94% ID/g, respectively.ConclusionMEF-loaded niosomes could be a hopeful candidate in cancer treatment due to their potent tumor uptake. Such high targeting was attributed to passive targeting of the nanosized niosomes and confirmed by radiokinetic evaluation.

Cyperus scariosus extract based greenly synthesized gold nanoparticles as colorimetric nanoprobe for Ni2+ detection and as antibacterial and photocatalytic agent

Nanoparticles (NPs) having diameter in the range of 1–100 nm has been extensively studied for their broad range applications in the field of catalysis, sensing, energy storage and biology. The NPs can be synthesized utilizing multiple approaches, such as sol–gel method, hydrothermal, chemical reduction and green synthesis etc. However, green synthesis utilizing the plant extract as reducing and capping agent has grabbed the special attention due to its eco-friendly, non-hazardous and cost-effective nature. Herein, green synthesis of gold nanoparticles (AuNPs) is being reported utilizing aqueous extract of Cyperus scariosus roots (CSRE) under sunlight irradiation. CSRE@AuNPs have been successfully characterized by UV–Visible and FTIR spectroscopy, Scanning electron microscopy (SEM), Energy-dispersive X-rayspectroscopy (EDX), zeta potential (ZP), dynamic light scattering (DLS) and powder diffraction analysis (PXRD). Average size of the CSRE@AuNPs has been found ∼50 nm. Due to appropriate band gap of CSRE@AuNPs in the range of visible light, these NPs have evaluated for the photocatalytic potential to degrade hazardous organic dye i.e., methylene blue (MB). The NPs were proved to be efficient catalyst by 80% degradation of MB dye in just 90 min exposure to sunlight. These NPs have also been screened for the selective sensing of heavy metal ions in spiked water. CSRE@AuNPs had shown selective colorimetric response for the detection of Ni2+ with limit of detection (LOD) of 118.5 nM and a linear range of 0–300 µM at optimized temperature of 40 °C at wide range of pH (3–9). The zeta potential and hydrodynamic size measurements were carried out to study the effect of Ni2+ on nanoparticle aggregation. A decrease in value of zeta potential from −34.4 to −0.116 mV (ignore the sign) and increase in value of DLS size from 53.2 to 7553 nm of the AuNPs was observed with an increase in concentration of Ni2+ ions from 0 to 300 µM. Furthermore, over 93% recovery and a relative standard deviation (RSD) of roughly 4% proved the effectiveness of this colorimetric nano-probe for Ni2+ detection in untreated natural water samples, such as river and tap water.

Emulsion stabilising capacity of sunflower meal depending on fraction protein content and particle size

SummarySunflower meal, as a high protein source, is usually utilised in animal feed, but other means of valorisation of this byproduct should be investigated in order to increase sunflower meal industrial functionality and therefore economic value. High protein content could suggest potential ability to stabilise food emulsions. Current study investigated the influence of sunflower meal protein content and particle size distribution in stabilisation of oil‐in‐water emulsions. Sunflower meal samples were characterised in terms of chemical and amino acid content and FTIR spectroscopy, while in the obtained emulsion samples creaming index, droplet size, droplet size distribution and zeta potential were determined. A relatively equal distribution of hydrophilic/hydrophobic amino acids (46% and 54%, respectively) was determined indicating a strong amphiphilic character of proteins and potentially effective emulsion‐stabilising properties. Further results suggested a positive influence of higher protein content (increasing from 16.78% to 42.56%) on lower creaming index values (lowering values from 84% to 32%, respectively). Protein content and particle size distribution strongly affected emulsion droplets sizes (ranging from 77.32 to 238.61 μm) and zeta potential values. Therefore, the evaluation of the obtained results suggested that high protein sunflower meal can be applied for the stabilisation of oil‐in‐water emulsions.

Insights into the engineering parameters and Ca-peptide chelation of whole fish: Chemistry, structure and in vitro digestibility characteristics

This research studied the engineering parameters of fish bone powder (FBP) and whole fish powder (WFP) and compared their nutritional and structural properties to fish meat powder in order to evaluate if FBP and WFP might be utilized as a food in the future. For FBP and WFP, the parameters used were rotation speed, milling gap, and sample: water, whereas milling speed, time, and powder: medium, respectively. According to the findings, the primary variables that enhanced stress intensity (SI) and stress number (SN), leading to particle sizes of 10 and 5 μm for WFP and FBP, respectively, were milling time, colloidal gap and sample: media. The FBP had significantly (P < 0.05) higher values of zeta potential (ζ) than the FBP. The phenomenon of Ca-peptide chelation in WFP was observed by peaks at 1548 and 3302 cm−1 (FTIR spectra) compared to that FBP and fish meat. The Ca bioavailability and protein digestibility of WFP were significantly (P < 0.05) higher (40 and 80%) than those of FBP (35 and 70%), most likely due to Ca-peptide chelation. The increased protein bioavailability was also demonstrated by WFP having significantly (P < 0.05) more essential amino acids (41.30%) than FBP (33.9%). The technoeconomic analysis revealed that, when land and equipment costs are excluded, the cost of WFP is less than that of fish flesh powder, and its yield (18–22%) is higher. The findings suggest the feasibility of adding WFP in food products with improved structural and in vitro digestibility characteristics.

Visible-light-driven photodegradation of methylene blue and doxycycline hydrochloride by waste-based S-scheme heterojunction photocatalyst Bi5O7I/PCN/tea waste biochar

Herein, we have reported a photocatalytic Bi5O7I, protonated g-C3N4 heterojunction with directional charge transfer channels provided by tea waste biochar to achieve effective e−/h+ pair isolation for the improved degradation of Methylene blue (MB) and Doxycycline hydrochloride (DCHCl). An S-scheme heterojunction was fabricated via the novel method that combined hydrothermal and ultrasonic dispersion, followed by an electrostatic self-assembly route. The as-fabricated Bi5O7I/protonated g-C3N4/Tea waste biochar heterojunction formed a strong contact at the interface, as supported by the electron microscopic results. As per the adsorption and photocatalytic degradation kinetics study, Bi5O7I/Tea waste biochar/protonated g-C3N4 (40 wt%) heterojunction showed a higher adsorption rate of 41.56% and 32% for MB and DCHCl within 30 min in the dark. Also, 92.02% MB and 90.21% DCHCl degradation rates in 60 and 90 min, respectively, are approximately 43 and 32 times higher than bare Bi5O7I and protonated g-C3N4 photocatalysts. The highest adsorption and degradation rate was achieved owing to the addition of Tea waste biochar and protonated g-C3N4 in a controlled ratio, and the sufficient interfacial contact between Bi5O7I and protonated g-C3N4 is for the improved isolation rate of e−/h+ pairs as evidenced by zeta potential values photoluminescence spectra as well as from scanning and transmission electron microscopy. Moreover, Bi5O7I/Tea waste biochar/protonated g-C3N4 (40 wt%) possessed high stability and recyclability after four consecutive cycles without much altering the degradation ability. Therefore, we believe that the as-fabricated Bi5O7I/Tea waste biochar/protonated g-C3N4 (40 wt%) provides new insight into the highly efficient S-scheme mechanisms significant for accelerating multicomponent photocatalytic redox reactions; while forming an effective visible light responsive candidate for treating wastewater.

Evaluation of heavy metal removal and antibiofilm efficiency of biologically synthesized chitosan- silver Nano-bio composite by a soil actinobacterium Glutamicibacter uratoxydans VRAK 24

Biological synthesis of nanoparticles is cost-effective as well as safer than physical and chemical methods. This study focuses on the biological synthesis of silver nanoparticles using Glutamicibacter uratoxydans which remains still unexplored. The synthesized silver nanoparticles are encapsulated with chitosan to prepare nanobiocomposite. Actinobacteria were isolated from mesophilic soil and screened for heavy metal resistance. The potent heavy metal resistant isolate was identified by 16SrRNA sequencing and used for the biological synthesis of silver particles. The characterization of chitosan- silver nano-bio composite was carried out by UV–Vis spectroscopy, FTIR spectroscopy, and XRD. Morphology was analyzed by scanning electron microscopy. The particle size and stability were studied using Dynamic light scattering and Zeta potential analysis. The nano-bio composite was tested for lead removal efficiency and antibiofilm activity. The potent isolate was identified as Glutamicibacter uratoxydans and it was named as Glutamicibacter uratoxydans VRAK 24. The UV spectra showed maximum absorbance at 410 nm. The FTIR spectra and XRD confirmed chitosan encapsulation with silver nanoparticle. The size of nanobiocomposite was found to be 0.376. The stability of nanobiocomposite recorded a zeta potential value of −5.37 mV. The lead removal efficiency was found to be 87.69 %. In addition, the nanobiocomposite exhibited highest anti-biofilm activity against S.aureus when compared to E.coli. The research findings, concluded that the synthesized nanobiocomposite showed better anti-biofilm activity. Also, nanobiocomposite was found to be a good adsorbent for the removal of heavy metal lead.

Effect of non-covalently bound polyphenols on the structural and functional properties of wheat germ protein

This study investigated the effects of epigallocatechin-3-gallate (EGCG), chlorogenic acid (CA), piceatannol (PIC) and ferulic acid (FA) on the conformational and functional properties of wheat germ protein (WGP). The WGP-polyphenol interaction was confirmed by native polyacrylamide gel electrophoresis and detection of polyphenol content in the complex. Among the four polyphenols, EGCG showed the highest binding affinity to WGP. Moreover, FT-IR analysis indicated that the polyphenols changed the secondary structure of WGP, inducing an enhancement in alpha-helix content and a reduction in β-sheet structure. Fluorescence spectrum analysis demonstrated the presence of polyphenols induced tertiary structure change of WGP, leading to the deconstruction and unfolding of protein. In addition, the main interaction force for WGP-EGCG was hydrogen bonding and van der Waals forces, and for WGP-CA complexes was electrostatic interaction, while interaction force for WGP-PIC and WGP-FA complexes were hydrophobic interaction. Moreover, the addition of polyphenols significantly increased the absolute value of zeta potential while decreased surface hydrophobicity and free sulfhydryl content of WGP. The solubility and functionality of WGP were mainly improved by CA and EGCG. The findings in this study suggest that WGP-polyphenol complexes have the potential to be applied as novel functional food ingredients.

Targeted delivery of essential oils of Salvia officinalis L to AGS cancer cells using PLA-spermine-PEG-FA

The MTT test was used in this study to evaluate anticancer potential of Salvia officinalis L's essential oil on AGS cells. The results showed that the Salvia officinalis L's essential oil has high potential anticancer activity against AGS cells. To improve the solubility of the essential oil and its targeted administration to AGS cells, poly lactic acid-spermine-poly ethylene glycol-folic acid (PLA-Spermine-PEG-FA) (FPSP) was utilized. For this purpose, Salvia officinalis L's essential oil and silver nanoparticles were encapsulated into the PLA-Spermine-PEG-FA (FPSP) using the solvent diffusion technique. Then, using transmission electron microscope (TEM) and dynamic light scattering (DLS), respectively, morphology, zeta potential, as well as average particle size characteristics of the nanoparticles were evaluated. The FPSP/essential oil nanoparticles (FPSP/EO) were spherical in shape and had an average particle size of 200–300 nm. The mean particle dimensions for both PSP/silver/EO and FPSP/silver/EO nanoparticles assemblies are measured at 236.52 ± 22.64 nm and 248.95 ± 28.17 nm, respectively. The results showed that the zeta potential values for PSP/silver/EO and FPSP/silver/EO were −18.3 ± 0.7 mV and −20.6 ± 1.3 mV, respectively. The results of this test showed that FPSP/Silver/EO significantly reduced the percentage of AGS cell viability better than EO and PSP/Silver/EO. The best treatment in this experiment was FPSP/Silver/EO at a concentration of 50 μL/mL and time 72 h. The minimum value of IC50 in FPSP/Silver/EO was observed as 21.11 μL/mL in 72 h.

Green syntheses of silk fibroin/wool keratin-protected Au[sbnd]Ag nanoclusters with enhanced fluorescence for multicolor and patterned anti-counterfeiting

Counterfeiting is a serious worldwide issue that threatens human health and economic security. How to apply anti-counterfeiting techniques to textile materials remains a great challenge. Herein, we report bimetallic AuAg nanoclusters (NCs) synthesized by one-step reduction of chloroauric acid (HAuCl4) and silver nitrate (AgNO3) with wool keratin (WK) as reducer and silk fibroin (SF) as stabilizer. The strongest orange-red fluorescence under ultraviolet light as well as the highest zeta potential absolute values of −27.97 mV were simultaneously realized in the optimal proportion Au-AgNCs2 (WK/SF is 3/2), which was further processed to a series of anti-counterfeiting films by blending with SF, silk sericin (SS), and polyvinyl alcohol (PVA). After successfully being numbered into fifteen colors, a dark blue-orange-dark red-dark blue cyclic fluorescent anti-counterfeiting color chart was designed. In addition, a two-Maxwell-unit model was constructed to assist with the microstructure analysis, which found that the formation of hydrogen bonds and the secondary structure transition from α-helices to β-sheets during stretching were responsible for improving the mechanical properties and the two-staged fracture curves of films, respectively. Finally, a patterned and multicolor fluorescence anti-counterfeiting fabric application was demonstrated by combining the color chart and screen printing, indicating the great potential in textile anti-counterfeiting.

Synthesis of carbon quantum dot synthesized using spent coffee ground as a biomass exhibiting visible-light-driven antimicrobial activity against foodborne pathogens

The aim of this study was to synthesize carbon quantum dot (CQD) exhibiting visible-light-driven (VLD) antimicrobial activity using spent coffee ground (SCG) as biomass. SCG was used to synthesize CQD through microwave treatment. It was confirmed that typical CQD was synthesized well based on morphology (high resolution transmission electron microscopy), size distribution (dynamic light scattering), and chemical structure (X-ray photoelectron spectroscopy) analyses. VLD antimicrobial activities of CQD synthesized from SCG against Staphylococcus aureus and Escherichia coli O157:H7 were found to be increased as pH decreased. Photodynamic properties of CQDs such as fluorescence quantum yield (FLQY), band gap energy (Eg), and fluorescence lifetime as photodynamic properties of CQDs related to VLD antimicrobial activity did not show any significant changes according to pH change. However, as pH decreased, negative zeta potential (mV) values of CQD and pathogenic bacteria gradually decreased. As a result, it was confirmed that CQD uptake into pathogens was gradually increased due to a decrease in repulsive force between them. In addition, it was found that as pH decreased, activities of enzymes (superoxide dismutase and catalase) known to scavenge reactive oxygen species (ROS) in cells decreased. In the presence of CQD, when visible light was applied, the amount of ROS generated inside cells increased as pH decreased. Based on these results, CQD synthesized from SCG was combined with organic acid (malic acid) for practical application in fresh produce (apple surface) washing. It was confirmed that such combination had an excellent control effect against pathogenic bacteria, suggesting that this strategy could be effectively utilized in the food industry.

Escherichia coli fatality dependence on oxidation level of graphite: Insights into membrane permeabilization and protein leakage

BackgroundGraphene oxide (GO) with different oxidation levels were evaluated for their bactericidal activities, with the aim to investigate the antibacterial mechanism by correlating the bactericidal efficacy with GO oxidation level. MethodsThe GO samples were synthesized and labelled as GO1, GO2, GO3 and GO4 using graphite/KMnO4 ratios of 1:3, 1:4, 1:5 and 1:6, respectively. Those samples were characterized and tested for antibacterial activity against Escherichia coli (E. coli). Significant findingsThis study revealed graphite transformation from multilayer stacks to monolayer wrinkled GO nanosheets with increasing KMnO4 dosage. The higher oxidized GO exhibited a lower negative zeta potential value, and higher O/C ratio. GO4 exhibited the lowest half maximal inhibitory concentration value at 161 µg mL−1, followed by GO3 (307 µg mL−1), GO2 (652 µg mL−1), and GO1 (1077 µg mL−1), indicating a strong correlation (R2=0.94) between oxidation level and bactericidal effectiveness. GO primarily interacts with the outer membrane through its hydrophobic surface, leading to permeabilized membrane (˃ 50 %), protein leakage (˃ 40 µg mg−1), significant morphological alterations, triggering reactive oxygen species production, and resulting in extensive damage to the entire bacterial cell. In summary, highly oxidized GO4 (O/C ratio of 0.54) demonstrated antibacterial potential for clinical use.

Effect of High-Hydrostatic-Pressure Treatment on the Physicochemical Properties of Kafirin.

The kafirin derived from Jin Nuo 3 sorghum underwent a high-hydrostatic-pressure (HHP) treatment of 100, 300, and 600 MPa for 10 min to investigate alterations in its physicochemical attributes. The findings exhibited a reduction in protein solubility, declining from 83% to 62%, consequent to the application of the HHP treatment. However, this treatment did not lead to subunit-specific aggregation. The absorption intensity of UV light diminished, and the peak fluorescence absorption wavelength exhibited a shift from 342 nm to 344 nm, indicating an increased polarity within the amino acid microenvironment. In an aqueous solution, the specific surface area expanded from 294.2 m2/kg to 304.5 m2/kg, while the average particle-size value in a 70% ethanol solution rose to 26.3 nm. Conversely, the zeta-potential value decreased from 3.4 mV to 1.3 mV, suggesting a propensity for aggregation in ethanol solutions. A notable rise in the intermolecular β-sheet content to 21.06% was observed, along with a shift in the peak denaturation temperature from 76.33 °C to 86.33 °C. Additionally, the content of disulfide bonds increased to 14.5 μmol/g. Collectively, the application of the HHP treatment not only enhanced the thermal stability but also induced a more ordered secondary structure within the kafirin.

Green synthesis of silver nanoparticles (AgNPs) by Lallemantia royleana leaf Extract: Their Bio-Pharmaceutical and catalytic properties

The study of the silver nanoparticles (AgNPs) synthesis based-green methods become more interesting recently due to their low-cost preparation, eco-friendly and non-toxic precursors. The present study approved the ability of the Lallemantia royleana (Benth. in Wall.) Benth. leaf extract for the synthesis of AgNPs for the first time. The synthesized AgNPs were physico-chemical characterized using ultraviolet–visible spectroscopy (UV–Vis), X-ray diffraction (XRD), Fourier Transform-Infrared Spectroscopy (FT-IR), zeta potential and transmission electron microscopy (TEM) analysis. The total phenols, flavonoids, anthocyanin, tannin contents, antioxidant, antimicrobial, anti-inflammatory, anti-arthritic and cytotoxic activities of L. royleana leaf extract and the synthesized AgNPs were investigated. The biocatalytic activity of prepared AgNPs was assessed on methylene blue as a pollutant organic dye. The TEM examination showed that the synthesized AgNPs were predominantly spherical with some mixed shapes and crystalline with average size 34.47 ± 1.6 nm, and showed a localized surface plasmon resonance (LSPR) peak at 425 nm. The zeta potential value was −24.1 mV indicating the stability of produced AgNPs. The new prepared AgNPs have lower total phenols, flavonoids, anthocyanin, tannin contents than L. royleana leaf extract. In addition, the new prepared AgNPs demonstrated the higher DPPH radical scavenging activity (87 %) and the ABTS radical scavenging activity (77 %) at the maximum prepared concentration of 250 μg mL−1 as compared to the L. royleana leaf extract (62 % and 58 %, respectively). The produced AgNPs also exhibited the higher antimicrobial activity against both the Gram-positive (Staphylococcus aureus and Bacillus cereus) and the Gram-negative (Escherichia coli and Shigella flexneri) bacteria and the Candida strains (Candida glabrata and Candida albicans) as compared to the L. royleana leaf extract. The resulting AgNPs indicated a dose-dependent anti-inflammatory effect on human red-blood cell (RBC) membrane stabilization assay and had more activity (72 %) compared to the L. royleana leaf extract (61 %) at 250 µg mL−1. The prepared AgNPs showed promising in vitro anti-arthritic activity evaluated by 73 % compared to 58 % in case of L. royleana leaf extract. The new produced AgNPs showed the higher cytotoxic effect against the human hepatoma (Hep-G2) and the human breast (MCF-7) cancer cells compared to the L. royleana leaf extract with 79.3 % and 77.2 % at 250 µg/mL, respectively. The obtained results revealed also that the green synthesized AgNPs were capable to catalyze MB dye. Therefore, the obtained results provide a promising route of the green synthesis of AgNPs using L. royleana leaf extract with considerable biopharmaceuticals and catalytic applications.

Formulation of selective hydrophobic deep eutectic oil-in-water nanoemulsion as green fungicides for mitigating anthracnose fungus Colletotrichum gloeosporioides

Hydrophobic deep eutectic nanoemulsions derived from fatty acids and terpenes (referred to as HyDEN) were introduced as potential nano-coating to effectively combat anthracnose during the postharvest preservation of fruits. Anthracnose primarily caused by the Colletotrichum gloeosporioides species is known for causing substantial damage to fruits. Synthetic fungicides have proven to be effective but come with environmental, health, and safety concerns. In this study, hydrophobic deep eutectic solvents (HDESs) were evaluated for their physical properties to identify the most suitable HDES for the formulation of HyDEN. Menthol-Thymol (MT) at 1:1 and 2:1 ratio met the criteria and was chosen for the formulation of HyDEN. HyDEN (MT-N 1:1) displayed a higher zeta potential value and smaller mean droplet diameter and then tested for its antifungal properties against C. gloeosporioides compared with selected antifungal agents. HyDEN (MT-N 1:1) exhibited strong antifungal activity against C. gloeosporioides and was attributed to its potent mode of action, binding affinity, and rapid onset compared to HDES and fungicide (Globus 5.5). This study also investigated how HyDEN (MT-N 1:1) affects mycelial growth, cell membrane permeability, and cellular leakage of C. gloeosporioides, highlighting its superior disruption of cell membranes compared to HDES and Globus 5.5. This research presents an eco-friendly alternative to the use of toxic chemicals and showcases an innovative and sustainable approach to controlling anthracnose in postharvest fruit preservation.

Intercalation vs Adsorption Strategies of Myo-Inositol Hexakisphosphate into Zn-Fe Layered Double Hydroxide: A Tiff between Anion Exchange and Coprecipitation.

Myo-inositol hexakisphosphates (IHPs) or phytates are the most abundant organic phosphates having the potential to serve as a phosphorus reserve in soil. Understanding the fate of IHP interaction with soil minerals tends to be crucial for its efficient storage and utilization as a slow-release organic phosphate fertilizer. We have systematically compared the effective intercalation strategy of a phytate onto Zn-Fe layered double hydroxide (LDH) acting as storage/carrier material through coprecipitation and anion exchange. Powder X-ray diffraction, X-ray photoelectron spectroscopy, elemental analysis, thermogravimetric analysis, FTIR spectra, and molecular modeling demonstrated the formation of phytate-intercalated Zn-Fe LDH through coprecipitation with a maximum loading of 41.34% (w/w) in the pH range of ∼9-10 in a vertical alignment through monolayer formation. No intercalation product was obtained from the anion exchange method, which was concluded based on the absence of shifting in the XRD (003) peak. A change in the zeta potential values from positive to negative and subsequent increase in solution pH, with decreasing phytate concentration, are suggestive of adsorption of IHP onto the LDH surface. The batch adsorption data were best fitted with Langmuir isotherm equation and followed the pseudo-second-order kinetic model. The maximum adsorption capacity was found to be 45.87 mg g-1 at a temperature of 25 ± 0.5 °C and pH 5.63.