Transmission Electron Microscopy Micrographs Research Articles

Combined depth-resolved cathodoluminescence spectroscopy and transmission electron microscopy on Al(Ga)N multi quantum well structures

A stack of five Al(Ga)N-based quantum wells is investigated by combined laterally and depth resolved cathodoluminescence (CL) spectroscopy in order to distinguish lateral and vertical inhomogeneities of these wells. Transmission electron microscopy (TEM) micrographs provide data for the real sample structure, which enters into the Monte-Carlo simulation of the depth-resolved CL measurements to refine the depth resolution. The comparison of these CL measurements to the results of electron energy loss spectra (EELS) allows to identify local thickness variations of the lower three quantum wells to be the origin of two different luminescence contributions to the overall spectrum. The differentiation of the two groups of quantum wells by depth-resolved CL is demonstrated.

Colloidal stability, cytotoxicity, and cellular uptake of HfO2 nanoparticles.

The colloidal stability, cytotoxicity, and cellular uptake of hafnium oxide (HfO2 ) nanoparticles (NPs) were investigated in vitro to assess safety and efficacy for use as a deliverable theranostic in nanomedicine. Monoclinic HfO2 NPs, ~60-90 nm in diameter and ellipsoidal in shape, were directly prepared without calcination by a hydrothermal synthesis at 83% yield. The as-prepared, bare HfO2 NPs exhibited colloidal stability in cell culture media for at least 10 days without significant agglomeration or settling. The viability (live/dead assay) of human epithelial cells (HeLa) and monocyte-derived macrophages (THP-1) did not fall below 95% of untreated cells after up to 24 h exposure to HfO2 NPs at concentrations up to 0.80 mg/ml. Similarly, the mitochondrial activity (MTT assay) of HeLa and THP-1 cells did not fall below 80% of untreated cells after up to 24 h exposure to HfO2 NPs at concentrations up to 0.40 mg/ml. Cellular uptake was confirmed and visualized in both HeLa and THP-1 cells by fluorescence microscopy of HfO2 NPs labeled with Cy5 and transmission electron microscopy (TEM) of bare HfO2 NPs. TEM micrographs provided direct observation of macropinocytosis and endosomal compartmentalization within 4h of exposure. Thus, the HfO2 NPs in this study exhibited colloidal stability, cytocompatibility, and cellular uptake for potential use as a deliverable theranostic in nanomedicine.

Effect of carbon nanotubes functionalization on properties of their nanocomposites with polycarbonate/poly(acrylonitrile‐butadiene‐styrene) matrix

AbstractIn this work, a comparative study evaluating the influence of different functionalization of carbon nanotubes on the properties of nanocomposites with polymeric matrix was performed. A 50/50 wt% polycarbonate (PC)/poly(acrylonitrile‐butadiene‐styrene) (ABS) blend was used as polymeric matrix of the nanocomposites. The comparison was made between nanocomposites reinforced with covalently functionalized multiwall carbon nanotubes (MWCNTf) and MWCNTf/nanoclay hybrid functionalization. The effect on the mechanical and morphological properties of the nanocomposites was evaluated through tensile and Izod impact tests and scanning electron microscopy and transmission electron microscopy (TEM) analyses. The thermal characterization of PC/ABS blends and nanocomposites was performed by differential scanning calorimetry (DSC). Results showed that both methods of functionalization of MWCNTs increased the stiffness and impact resistance of the nanocomposites. TEM micrographs indicated the preferred location of the reinforcements in the SAN phase of ABS. Results from DSC indicated an increase in the thermal resistance of the nanocomposites.

Mechanical response of dislocation interaction with grain boundary in ultrafine-grained interstitial-free steel

Interstitial-free (IF) steel with ultrafine-grained (UFG) size was used to clarify the underlying mechanisms of the ‘extra-hardening’ behavior from the Hall-Petch plot and the discontinuous yielding behavior from axial tensile tests. Using transmission electron microscopy (TEM) at different tensile strains, it was found that the TEM micrographs for the bulk sample of the UFG IF steel showed a decrease in dislocation density in the grain interior after experiencing a micro tensile strain of 1.0% before macro-yielding. Additionally, an increase in dislocation density was found in the grain interior, with a micro tensile strain of 15% in the necking region after macro-yielding. In-situ compression tests in a TEM for micropillars were performed to directly observe the motion of dislocations and corresponding interactions with grain boundaries in UFG IF steel. Before macro-yielding, pre-existing dislocations in the grain interior moved toward the grain boundary, wherein they were then absorbed. The dislocation density decreased significantly due to the annihilation, which was accompanied by an increase in load during pre-yielding. The decrease in dislocation density in the grain interior of the micropillar is consistent with the results obtained from the bulk sample. After macro-yielding, the burst-like dislocation emission emerged from the grain boundary, leading to a yield drop and a discontinuous yielding behavior. Furthermore, the higher yield stress and the yield drop in the UFG IF steel can be understood by the decrease in dislocation density according to a combination of the Orowan model as well as the Johnston-Gilman model.

Effect of Niobium and Titanium Addition on Formation of Second Phase Particles in CHQ Steel Using Transmission Electron Microscope

It is common practice that formation of second phase particles such as nitrides or carbides in the steel matrix has significant role to control the grain size of steel. An attempt is made in the present research work to find out the role of nitrogen to form the nitride particles either with Al, Ti, B, Cr or Si. Two steel samples Steel-A and Steel-B with same titanium and aluminum weight percent in the chemical composition were obtained in hot rolled conditions from international market with only the difference of presence of Niobium in Steel-A. Solution heat treatment was performed at 1350°C with 60 minutes holding time in protherm heat treatment furnace available locally was used to dissolve the particles and then steel samples were reheat treated at 800°C with holding time of 60 minutes and water quenched and microstructure was revealed. Transmission electron microscope connected with Ehlers-Danlos Syndrome (EDS) was used to reveal the morphology of second phase particles. Both samples for a high resolution power Transmission Electron Microscopy (TEM) (Jeol JEM 3010) analysis were prepared by using carbon extraction replica method in 5% Nital solution as an etching technique. Both samples were then caught in copper grid of 3mm for using TEM analysis. TEM micrographs clearly revealed the second phase particles in the matrix of steel. The EDS peaks were studied and it was found that the peaks showed the titanium peaks in both the samples A and B and surprisingly there was no any peak found for aluminum. Stoichiometric calculations were carried out and it was found that weight percent nitrogen required for forming TiN is 0.0073, however the total nitrogen present in both the steels A and B is 0.0058 and 0.0061 respectively. That means that all the nitrogen present in the steel matrix was consumed by titanium to form the Titanium Nitride (TiN) so there was no nitrogen remain to fulfil the requirement of aluminum to form the Aluminum Nitride (AlN) particles.

Physical properties of Al-doped cobalt nanoferrite prepared by citrate–nitrate auto combustion method

Cobalt aluminum ferrites have been synthesized by citrate–nitrate auto combustion method. To obtain different crystallite sizes, the prepared powder was heated at different temperatures. X-ray diffraction (XRD) measurements showed that all the prepared samples were crystalized in single phase cubic spinel structure. Different heat treatments lead to different particle sizes which was confirmed by transmission electron microscopy (TEM) micrograph. The crystallite size (D) of the prepared samples ranges from 5 to 37 nm. The structure and elastic properties were investigated using Fourier-transform infrared (FTIR) spectroscopy. The elastic moduli and Debye temperature were calculated out of the FTIR results. The magnetic properties were studied using vibrating sample magnetometer (VSM) and the magnetic parameters; saturation magnetization ( $$M_{\text {S}}$$ ) and coercitvity ( $$H_{\text {c}}$$ ) were determined. The $$M_{\text {S}}$$ and $$H_{\text {c}}$$ size dependence of CoFeAlO $$_{4}$$ nanoparticles introduce a distinctive behaviour; from a structure with multi magnetic domains ( $$D> 9$$ nm) to that without magnetic domains (single domain structure) below $$D= 9$$ nm. Interestingly, the signature of the change from multi-domain to a single magnetic domain is reflected in the size dependence of the elastic moduli and Debye temperature obtained from FTIR results.

Synthesis, Characterization, and Cytotoxicity Evaluation of Polyethylene Glycol-Coated Iron Oxide Nanoparticles for Radiotherapy Application

Background:Treatment methods for cancer that are widely being utilized affect both normal and cancerous cells. We report synthesis polyethylene glycol (PEG)-coated Fe3O4 nanoparticles (NPs) and its characteristic properties and appraise its potential as a promising radiation sensitizer candidate in radiotherapy that improves cancer treatment and reduces side effects of radiation.Materials and methods:PEG-coated Fe3O4 NPs were synthesized by chemical coprecipitation method and characterized by studying their size, structure, functional group, stability, magnetization, and cytotoxicity using different techniques. X-ray powder diffraction, Fourier transform infrared spectroscopy, and thermogravimetric analysis results show that Fe3O4 NPs have been functionalized with PEG molecules during the course of synthesis.ResultsSynthesized NPs have good stability based on zeta-potential study. Dynamic light-scattering results reveal that PEG-coated Fe3O4 has a greater hydrodynamic size than bare Fe3O4. Transmission electron microscopy (TEM) micrograph exhibited that NPs are roughly spherical with size in range of 10–20 nm. Saturation magnetization value of PEG-coated and bare Fe3O4 also confirms coating and shows superparamagnetic behavior. Cytotoxicity evaluation study indicated that PEG-coated Fe3O4 is biocompatible on L929 and toxic on Michigan Cancer Foundation-7 (MCF-7) (breast cancer cells).Conclusion:These characterized properties of PEG-coated Fe3O4 NPs show that it could be used as a potential radiosensitizer candidate in radiotherapy to significantly improve cancer treatment and minimize painful side effects of radiation.

Environmental benign synthesis and characterization of nickel oxide nanoparticles using chicken egg white as template and evaluations of their antibacterial/antifungal activities

Synthetic preparation of metal-based nanoparticles is harmful to human being because of the environmental pollution. To overcome the hurdles in synthesis of nanoparticles, the biogenic synthesis of nickel oxide nanoparticles (NiO NPs) has been performed by a simple, cost effective, non-toxic, and environmentally friendly sol–gel method using fresh chicken egg-white (CEW) as reducing and stabilizing agent. The NiO NPs so synthesized were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), Fourier transform infrared (FTIR). The powder XRD pattern studies confirmed the formation of NiO NPs and the average crystallite size was found to be 30 nm. The FESEM and TEM micrographs suggested that spherical shape of prepared NiO NPs with diameter range 40 to 50 nm. The FTIR spectrum of prepared nanoparticles confirms the Ni and O metal oxide bonding. The antimicrobial activities of synthesized NiO NPs have also been investigated for some Gram positive and Gram-negative bacterial as well as some fungal strains and encouraging results were obtained and discussed at length.

Deep-learning in situ classification of HIV-1 virion morphology

Transmission electron microscopy (TEM) has a multitude of uses in biomedical imaging due to its ability to discern ultrastructure morphology at the nanometer scale. Through its ability to directly visualize virus particles, TEM has for several decades been an invaluable tool in the virologist’s toolbox. As applied to HIV-1 research, TEM is critical to evaluate activities of inhibitors that block the maturation and morphogenesis steps of the virus lifecycle. However, both the preparation and analysis of TEM micrographs requires time consuming manual labor. Through the dedicated use of computer vision frameworks and machine learning techniques, we have developed a convolutional neural network backbone of a two-stage Region Based Convolutional Neural Network (RCNN) capable of identifying, segmenting and classifying HIV-1 virions at different stages of maturation and morphogenesis. Our results outperformed common RCNN backbones, achieving 80.0% mean Average Precision on a diverse set of micrographs comprising different experimental samples and magnifications. We expect that this tool will be of interest to a broad range of researchers.

Rhombohedral boron nitride epitaxy on ZrB2

Epitaxial rhombohedral boron nitride (r-BN) films were deposited on ZrB2(0001)/4H-SiC(0001) by chemical vapor deposition at 1485 °C from the reaction of triethylboron and ammonia and with a minute amount of silane (SiH4). X-ray diffraction (XRD) φ-scans yield the epitaxial relationships of r-BN(0001)∥ZrB2(0001)out-of-plane and r-BN[112¯0]∥ZrB2[112¯0] in-plane. Cross-sectional transmission electron microscopy (TEM) micrographs showed that epitaxial growth of r-BN films prevails to ∼10 nm. Both XRD and TEM demonstrate the formation of carbon- and nitrogen-containing cubic inclusions at the ZrB2 surface. Quantitative analysis from x-ray photoelectron spectroscopy of the r-BN films shows B/N ratios between 1.30 and 1.20 and an O content of 3–4 at. %. Plan-view scanning electron microscopy images reveal a surface morphology where an amorphous material comprising B, C, and N is surrounding the epitaxial twinned r-BN crystals.

Study of the Antibacterial Property of Tea Tree Oil and Its Incorporation Into Poly(Lactic Acid)‐montmorillonite Clay Bionanocomposites

AbstractThe presence of microorganisms in skin wounds can lead to infections that hamper the healing process; therefore, growing interest is given to the development of antimicrobial dressing. This study evaluates the ability of tea tree essential oil (EO) to eliminate resistant microorganisms, and new antibacterial bionanocomposites are prepared in two steps, namely sonication followed by melt mixing. Montmorillonite clay (MMT) and poly(acid lactic) (PLA) are chosen for constituting a polymer‐clay bionanocomposite for application in wound dressing. MMT retains and promotes a controlled release of the drug into the wound. Synthetic PLA is approved by the Food and Drug Administration for wound dressing applications. Disk diffusion tests evaluate the antimicrobial properties of tea tree oil, and X‐ray diffraction (XRD) and transmission electron microscopy (TEM) analyzed the extent of clay intercalation/exfoliation. Tea tree essential oil is effective against Escherichia coli and Staphylococcus aureus bacteria. According to the XRD results, the preparation method used can promote oil incorporation into the MMT galleries. TEM micrographs corroborated such results showing the coexistence of intercalated‐exfoliated structures in the bionanocomposites. As a conclusion, the produced bionanocomposites with tea tree essential oil are interesting antibacterial material to be used in wound dressing applications.

Pycotem: An open source toolbox for online crystal defect characterization from TEM imaging and diffraction.

We present a series of tools working together that facilitate the determination of dislocation Burgers vectors and slip planes, interface plane normals and misorientation between two crystals from a series of Transmission Electron Microscopy (TEM) micrographs and diffraction patterns. To that purpose, we developed graphical user interface programs that allow crystal orientation determination from spot diffraction patterns taken at various tilt angles or from Kikuchi patterns crystal representation from stereographic projection plots and determination of geometrical features from series of conventional images taken at different tilt angles. We present working examples that allow a faster and easier way to analyse data that can especially be retrieved during in situ straining experiments where dislocations and grain boundaries need to be characterized. More generally, these tools target material scientists interested in daily microstructural characterization inTEM.

Fungus- (Alternaria sp.) Mediated Silver Nanoparticles Synthesis, Characterization, and Screening of Antifungal Activity against Some Phytopathogens

The scientific consensus is now on developing a biocontrol agent that can cause cellular metabolic reprogramming against agricultural pathogens. Biosynthesis of silver nanoparticles was performed by using phytopathogenic fungi (Alternaria sp.) isolated from banana cultivated soil. Alternaria sp. can grow very fast and produce high enough bioactive compounds. This study aims to biosynthesize silver nanoparticles (AgNPs) using fungal Alternaria sp.’s metabolites as a safe antifungal agent against plant pathogenic fungi (Fusarium spp. and Alternaria sp.). To visualize the formation of AgNPs, analytical instruments were used, such as ultraviolet-visible (UV-Vis) spectroscopy, Fourier-transform infrared (FTIR) spectroscopy, scanning transmission electron microscopy (STEM), energy dispersive X-ray (EDX), and elemental mapping. The UV-visible spectra showed a peak at 435 nm. Analysis of scanning transmission electron microscopy (STEM) micrographs evidenced that the size of synthesized silver nanoparticles ranged between 3 and 10 nm. The resulting AgNPs showed distinct antifungal activity against selected plant pathogenic fungi. Synthesized AgNPs have demonstrated remarkable potential for the use of antifungal compounds to combat plant diseases.

Ti–Cu Coatings Deposited by a Combination of HiPIMS and DC Magnetron Sputtering: The Role of Vacuum Annealing on Cu Diffusion, Microstructure, and Corrosion Resistance

Titanium-copper (Ti–Cu) coatings have attracted extensive attention in the surface modification of industrial and biomedical materials due to their excellent physical and chemical properties and biocompatibility. Here, Ti–Cu coatings are fabricated using a combination of high-power pulsed magnetron sputtering (HPPMS; also known as high power impulse magnetron sputtering (HiPIMS)) and DC magnetron sputtering followed by vacuum annealing at varied temperatures (300, 400, and 500 °C). X-ray diffraction (XRD), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS) data showed that Ti, Cu, and CuTi3 are mainly formed in the coatings before annealing, while Ti3O, Cu2O, and CuTi3 are the main compounds present in the annealed coatings. The cross-sectional TEM micrographs and corresponding EDS results provided evidence that Ti is mainly present on the surface and interfaces of the silicon substrate and the Ti–Cu coatings annealed at 500 °C, while the bulk of the coatings is enriched with Cu. The resistivity of the coatings decreased with increasing the annealing temperature from 300 to 500 °C. Based on self-corrosion current density data, the Ti–Cu coating annealed at 300 °C showed similar corrosion performance compared to the as-deposited Ti–Cu coating, while the corrosion rate increased for the Ti–Cu coatings annealed at 400 and 500 °C. Stable release of copper ions in PBS (cumulative released concentration of 0.8–1.0 μM) for up to 30 days was achieved for all the annealed coatings. Altogether, the results demonstrate that vacuum annealing is a simple and viable approach to tune the Cu diffusion and microstructure of the Ti–Cu coatings, thereby modulating their electrical resistivity, corrosion performance, and Cu ion release behavior.

Structural and physicochemical properties of Rheum emodi mediated Mg(OH)2 nanoparticles and their antibacterial and cytotoxic potential.

In the present investigation, Rheum emodi roots extract mediated magnesium hydroxide nanoparticles [Mg(OH)2 NPs] through the bio-inspired experimental technique were synthesised. Mg(OH)2 NPs were characterised by using various characterisation techniques such as field emission scanning electron microscopy, transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), and ultraviolet-visible spectroscopy. The formation of Mg(OH)2 NPs was confirmed by X-ray diffraction. The structural analysis confirmed the hexagonal crystal symmetry of Mg(OH)2 NPs with space group P-3m1 and space group no. 164 using the Rietveld refinement technique. TEM micrographs illustrated the nano-size formation of Mg(OH)2 NPs of spherical shape and size ∼14.86 nm. With the aid of FTIR data, plant metabolites such as anthraquinones have been identified as a stabilising and reducing agent for the synthesis of biogenic Mg(OH)2 NPs. The synthesised Mg(OH)2 NPs showed antimicrobial and cytotoxic potential against Gram-negative and Gram-positive bacteria such as Escherichia coli (ATCC 25922) and Staphylococcus aureus (ATCC 25923) and MDA-MB-231 human breast cancer cell lines.

The formate electrooxidation on Pt/C and PtSnO2/C nanoparticles in alkaline media: The effect of morphology and SnO2 on the platinum catalytic activity

Pt/C and PtSnO2/C electrocatalysts with and without cubic preferential morphology were used for formate electrooxidation reaction (FER) in alkaline medium. The synthesis of catalysts was carried out by alcohol reduction method using KBr as a shape directing agent (Bromide Anion Exchange method - BAE). The X-ray diffraction (XRD) showed characteristic peaks of the Pt face-centered cubic (FCC) structure, as well as cassiterite SnO2. The Transmission Electron Microscopy (TEM) and Scanning Transmission Electron Microscopy (STEM) micrographs show SnO2 dispersed onto carbon support and adjacent to the Pt nanoparticles (NPs), as well as cubic Pt NPs. The cyclic voltammetry (CV) measurements show that the current density peak for FER on Pt/C (100) is 2.40 times higher than on Pt/C polycrystalline (poly). The current density at end of chronoamperometry (CA) analysis on PtSnO2/C poly was 1.33 and 5.29 times higher than on Pt/C (100) and Pt/C poly, respectively. The presence of SnO2 and the (100) facets of platinum cubic morphology might prevent platinum surface deactivation caused by intermediates formed during the FER process.

The impact of curcumin-graphene based nanoformulation on cellular interaction and redox-activated apoptosis: An in vitro colon cancer study

Natural plants derivatives have gained enormous merits in cancer therapy applications upon formulation with nanomaterials. Curcumin, as a popular research focus has acquired such improvements surpassing its disadvantageous low bioavailability. To this point, the available research data had confirmed the importance of nanomaterial type in orienting cellular response and provoking different toxicological and death mechanisms that may range from physical membrane damage to intracellular changes. This in turn underlines the poorly studied field of nanoformulation interaction with cells as the key determinant in toxicology outcomes. In this work, curcumin-AuNPs-reduced graphene oxide nanocomposite (CAG) was implemented as a model, to study the impact on cellular membrane integrity and the possible redox changes using colon cancer in vitro cell lines (HT-29 and SW-948), representing drug-responsive and resistant subtypes. Morphological and biochemical methods of transmission electron microscopy (TEM), apoptosis assay, reactive oxygen species (ROS) and antioxidants glutathione and superoxide dismutase (GSH and SOD) levels were examined with consideration to suitable protocols and vital optimizations. TEM micrographs proved endocytic uptake with succeeding cytoplasm deposition, which unlike other nanomaterials studied previously, conserved membrane integrity allowing intracellular cytotoxic mechanism. Apoptosis was confirmed with gold-standard morphological features observed in micrographs, while redox parameters revealed a time-dependent increase in ROS accompanied with regressive GSH and SOD levels. Collectively, this work demonstrates the success of graphene as a platform for curcumin intracellular delivery and cytotoxicity, and further highlights the importance of suitable in vitro methods to be used for nanomaterial validation.

Self-Assembly of Switchable Protein Nanocages via Allosteric Effect

Protein cages have promising applications in highly efficient gene transportation. Many methods of engineering protein–interface interactions have been developed to build such viral mimics. Missing...

Gamma irradiation influence on mechanical, thermal and conductivity properties of hybrid carbon nanotubes/montmorillonite nanocomposites

A thermoplastic elastomer (TPE) based nanocomposite with the same weight ratio of hybrid nanofillers composed of carbon nanotubes (CNTs) and montmorillonite nanoclay (DK4) was prepared using a melt blending technique with an internal mixer. The TPE composite was blended from polylactic acid (PLA), liquid natural rubber (LNR) as a compatibilizer and natural rubber (NR) in a volume ratio of 70:10:20, respectively. The weight ratio of CNTs and DK4 was 2.5 wt%. The prepared samples were exposed to gamma radiation at range of 0–250 kGy. After exposure to gamma radiation, the mechanical, thermo-mechanical, thermal and electrical conductivity properties of the composites were significantly higher than unirradiated TPE composites as the irradiation doses increased up to 150 kGy. Transmission electron microscopy (TEM) micrographs revealed the good distribution and interaction between the nano-fillers and the matrix in the prepared TPE hybrid nanocomposites. In summary, the findings from this work definite that gamma irradiation might be a viable treatment to improve the properties of TPE nanocomposite for electronic packaging applications.

Peptide Extracts from Native Lactic Acid Bacteria Generate Ghost Cells and Spheroplasts upon Interaction with Salmonella enterica, as Promising Food Antimicrobials.

Protecting foods from contamination applying peptides produced by lactic acid bacteria is a promising strategy to increase the food quality and safety. Interacting with the pathogen membranes might produce visible changes in shape or cell wall damage. Previously, we showed that the peptides produced by Lactobacillus plantarum UTNGt2, Lactobacillus plantarum UTNCys5-4, and Lactococcus lactis subsp. lactis UTNGt28 exhibit a broad spectrum of antibacterial activity against several foodborne pathogens in vitro. In this study, their possible mode of action against the commensal microorganism Salmonella enterica subsp. enterica ATCC51741 was investigated. The target membrane permeability was determined by detection of beta-galactosidase release from ONPG (o-nitro-phenyl-L-D-galactoside) substrate and changes in the whole protein profile indicating that the peptide extracts destroy the membrane integrity and may induce breaks in membrane proteins to some extent. The release of aromatic molecules such as DNA/RNA was detected after the interaction of Salmonella with the peptide extract. Transmission electronic microscopy (TEM) micrographs depicted at least four simultaneous secondary events after the peptide extract treatment underlying their antimicrobial actions, including morphological alterations of the membrane. Spheroplast and filament formation, vacuolation, and DNA relaxation were identified as the principal events from the Gt2 and Cys5-4 peptide extracts, while Gt28 induced the formation of ghost cells by release of cytoplasmic content, filaments, and separation of cell envelope layers. Gel retarding assays indicate that the Gt2 and Gt28 peptide extracts are clearly binding the Salmonella DNA, while Cys5-4 partially interacted with Salmonella genomic DNA. These results increased our knowledge about the inhibitory mechanism employed by several peptide extracts from native lactic acid bacteria against Salmonella. Further, we shall develop peptide-based formulation and evaluate their biocontrol effect in the food chains.