Improvement Of Antibacterial Properties Research Articles

Pectin Film Fortified with Zein Nanoparticles and Fe3+-Encapsulated Propolis Extract for Enhanced Fruit Preservation

In this study, pectin served as the film matrix while propolis extract (PPE) acted as both an antibacterial agent and antioxidant. Utilizing the encapsulation of zein nanoparticles and cross-linking of Fe3+ with pectin molecules, a dual encapsulation system of PPE in the pectin film was successfully achieved, resulting in antibacterial and antioxidant pectin films. The effects of incorporating PPE, zein, and Fe3+ on various properties of the pectin films were investigated. Additionally, the impact of zein nanoparticle encapsulation and Fe3+ dual encapsulation systems on the release characteristics of PPE in the pectin films was examined. Characterization techniques including FTIR, SEM, XRD crystal diffraction, and thermogravimetric analysis were employed to analyze the interactions, microstructure, crystal structure, and thermal stability of the films. The results showed that the double cross-linking of zein and Fe3+ led to a reduction in the moisture content of the pectin film by approximately 46%, a decrease in water vapor permeability by about 19%, an almost doubling of tensile strength and antioxidant activity, and a significant improvement in antibacterial properties. Additionally, the incorporation of zein and Fe3+ enhanced the release characteristics of PPE in the pectin films. Notably, the developed composite coating demonstrated improved preservation properties during the storage of strawberry fruits.

Antibacterial effect of surface-modified Zr50Cu50 metallic glass

Zr-based metallic glasses generally have an amorphous zirconium oxide film that strongly inhibits further oxidation. However, surface defects may deteriorate the glass stability of the amorphous oxide film, leading to the formation of a thick natural oxide layer. In this study, we demonstrated that the change in the oxidation behavior of a melt-spun Zr50Cu50 metallic glass foil caused by the surface casting defects on its wheel side can lead to a dramatic improvement in antibacterial properties. The superior antibacterial properties of the wheel side was attributed to the metallic Cu islands exposed on the surface.

In Situ Surface-Directed Assembly of 2D Metal Nanoplatelets for Drug-Free Treatment of Antibiotic-Resistant Bacteria.

The development of antibiotic resistance among bacterial strains is a major global public health concern. To address this, drug-free antibacterial approaches are needed. Copper surfaces have long been known for their antibacterial properties. In this work, a one-step surface modification technique is used to assemble 2D copper chloride nanoplatelets directly onto copper surfaces such as copper tape, transmission electron microscopy (TEM) grids, electrodes, and granules. The nanoplatelets are formed using copper ions from the copper surfaces, enabling their direct assembly onto these surfaces in a one-step process that does not require separate nanoparticle synthesis. The synthesis of the nanoplatelets is confirmed with TEM, scanning electron microscopy, energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FT-IR). Antibacterial properties of the Cu nanoplatelets are demonstrated in multidrug-resistant (MDR) Escherichia coli, MDR Acinetobacter baumannii, MDR Staphylococcus aureus, E.coli, and Streptococcus mutans. Nanoplatelets lead to a marked improvement in antibacterial properties compared to the copper surfaces alone, affecting bacterial cell morphology, preventing bacterial cell division, reducing their viability, damaging bacterial DNA, and altering protein expression. This work presents a robust method to directly assemble copper nanoplatelets onto any copper surface to imbue it with improved antibacterial properties.

Antibacterial Optimization of Highly Deformed Titanium Alloys for Spinal Implants.

The goal of the work was to develop materials dedicated to spine surgery that minimized the potential for infection originating from the transfer of bacteria during long surgeries. The bacteria form biofilms, causing implant loosening, pain and finally, a risk of paralysis for patients. Our strategy focused both on improvement of antibacterial properties against bacteria adhesion and on wear and corrosion resistance of tools for spine surgery. Further, a ~35% decrease in implant and tool dimensions was expected by introducing ultrahigh-strength titanium alloys for less-invasive surgeries. The tested materials, in the form of thin, multi-layered coatings, showed nanocrystalline microstructures. Performed direct-cytotoxicity studies (including lactate dehydrogenase activity measurement) showed that there was a low probability of adverse effects on surrounding SAOS-2 (Homo sapiens bone osteosarcoma) cells. The microbiological studies (e.g., ISO 22196 contact tests) showed that implanting Ag nanoparticles into Ti/TixN coatings inhibited the growth of E. coli and S. aureus cells and reduced their adhesion to the material surface. These findings suggest that Ag-nanoparticles present in implant coatings may potentially minimize infection risk and lower inherent stress.

Hybrid ZnO/chitosan antimicrobial coatings with enhanced mechanical and bioactive properties for titanium implants

A biocomposite coating comprising chitosan and ZnO deposited on a porous Ti oxide is developed to avoid orthopedic and dental implant-related infections. The coating comprised of an inner layer of nanoporous TiO2 and the outer layer of the chitosan matrix with ZnO nanoparticles. Microbiological tests show that chitosan coating is effective against Escherichia coli (E. coli), however, its ability to inhibit bacterial adhesion is very limited. A 1.2-fold increase in the antibacterial activity of chitosan/ZnO coating against E. coli was detected as compared to the chitosan coating alone, and the chitosan/ZnO efficiently inhibited biofilm formation. In addition, the chitosan/ZnO coating exhibited improved bioactivity compared to the chitosan coating. The improvement in antibacterial properties and bioactivity of the chitosan/ZnO coating is attributed to the release of Zn2+ ions. The critical force of scratching the chitosan/ZnO coating was approximately twice that of the chitosan coating. The potentiodynamic polarization results confirmed that the corrosion resistance of the implant with ZnO/chitosan/Ti structure was improved. In addition, cytocompatibility evaluation indicated that the chitosan/ZnO coating has good cytocompatibility in MG-63 cells as compared to pure Ti.

The antimicrobial effect of grapefruit peel essential oil and its nanoemulsion on fish spoilage bacteria and food-borne pathogens

In the study, improvement in antibacterial properties of grapefruit peel essential oil after the nanoemulsification process was investigated. The essential oil composition was characterized using GC-MS, with d-Limonene being the main identified compound (82.86%). The antibacterial properties against common food-borne pathogens (Staphylococcus aureus, Enterococcus faecalis, Klebsiella pneumoniaand Salmonella Paratyphi A) as well as 6 fish-spoilage bacteria isolated from 4 spoiled fish species: mackerel, sardine, anchovy and rainbow trout, have been evaluated using paper disc diffusion, MIC and MBC methods. The grapefruit peel essential oil showed bacteriostatic properties against the majority of tested bacterial strains, however, only the growth of Salmonella parathypi A, Vibrio vulnificus and Seratialique faciens was inhibited by the essential oil in the concentration up to 25 mg/mL. Incorporation of essential oil into the nanoemulsion system resulted in increased bacteriostatic potency when the oil concentration in the nanoemulsion were considered, however, no bactericidal effect was observed, which was probably due to too low concentration of essential oil in the nanoemulsion system. The improvement in the nanoemulsion preparation method and formulation should be investigated to further improve its antibacterial properties.

Antibacterial effect of TiO2 nanoparticles modified with APTES

In this paper, the antibacterial properties of TiO2 photocatalysts modified by 3-aminopropyltriethoxysilane (APTES) are presented. It has been observed that the APTES modification enhancement of antibacterial efficiency (against Escherichia coli ATCC 29425) under artificial solar light (ASL). The results showed that all modified titania had higher disinfection efficiencies than starting TiO2. For TiO2-4h-120 °C-300 a total sample elimination of the E. coli was achieved after 180 min of ASL irradiation. Improvement of antibacterial properties was attributed to the changes in the surface properties, i.e. zeta potential.

Improvement in antibacterial properties and cytocompatibility of titanium by fluorine and oxygen dual plasma-based surface modification

A versatile strategy to endow biomaterials with antibacterial ability and compromising cytocompatibility is highly desirable to solve serious infection problem of biomaterial implants. In this study, titanium (cp-Ti) was treated by a plasma enhanced fluorine (F) and oxygen (O) mono/dual chemical vapor deposition to obtain nano-functional coatings with improved antibacterial properties and biocompatibility. Using this platform, the antibacterial effect and the osteoblasts behavior were investigated in vitro. Meanwhile, the corrosion resistance of the fluoride coatings was also concerned. The fluorine-deposited samples can effectively kill Staphylococcus aureus and have adequate antibacterial properties. More importantly, the F and O dual-deposited coatings show the better sustaining antibacterial property after immersion in 0.9%NaCl solution up to 7 days than that of F mono-deposited coatings. Besides, the cell compatibility tests indicate that the fluorine-deposited samples have no appreciable influence on the osteoblast viability and proliferation, but promote differentiation compared to the cp-Ti and O-Ti samples. F and O incorporation even shows some favorable effect on promoting cell spreading. Further, the electrochemical results demonstrate the F and O dual-deposited coating exhibiting an improved corrosion resistance due to the formation of titanium-oxygen compounds on surface. The F and O incorporated coating which provides improved antibacterial ability and biocompatibility has attractive applications in orthopedics, dentistry, and other biomedical devices.

Creating extended antimicrobial property in paper by means of Ag and nanohybrids of montmorillonite (MMT)

Abstract Silver-clay nanohybrids based on silver nanoparticles (AgNPs) with montmorillonit (MMT) and milled MMT, shortly AgMMTnano and AgMMTmilled, have been prepared to improve the performance of antibacterial properties of paper. The results obtained by dynamic light scattering indicated the presence of silver particles in the nanometer range, which have a great accumulation tendency. The results of AAS and ICP-AES tests showed that nanosilver amount in the AgMMTmilled was doubled compared to the AgMMTnano, but according to the EDX results, the amount of nanosilver in paper treated with the former was less than in the latter. FE-SEM images showed that the dimensions of deposited nanosilver on the surface of clay were smaller than in case of AgNPs alone. Papers treated with nanohybrids had better antibacterial properties compared to that prepared by naked nanosilver. It was also found that the antibacterial property of papers treated with AgMMTnano were more stable during three-stage tests compared to those with AgMMTmilled. Nanohybrids with Ag conc. more than 15 ppm, especially hybrids with Ag conc. of 50 ppm, result in a significant improvement in antibacterial properties of paper. It can be concluded that silver-clay nanohybrid with a 25-ppm concentration of nanosilver could be the best and most economic antibacterial component.

Antibacterial properties of silver doped TiO2 nanoparticles synthesized via sol-gel technique

In this work, antibacterial, micro-structural, and fluorescence properties of silver (Ag) doped TiO2 nanoparticles were studied to analyze the effect of silver for effective improvement in antibacterial properties of TiO2. Antibacterial properties of pure TiO2 and Ag-TiO2 was studied using Escherichia coli, Pseudomonas aeruginosa as Gram Negative and Bacillus subtilis, Staphylococcus aureus as Gram positive bacteria, as a model for Agar disc diffusion assay method. The concept of inhibition zone diameter was applied to observe the antibacterial activity of TiO2 and Ag-TiO2. It was observed that the antibacterial activity of TiO2 improves with doping of Ag. Fluorescence spectra confirm the red shift in band edge emission at excitation wavelength of 360 nm which shows effective fluorescence properties of these nanoparticles. Microstructures of these nanoparticles have studied with the help of transmission electron microscopy (TEM) and atomic force microscopy (AFM).

New nanocomposite design from zeolite and poly(lactic acid)

We studied the effect of zeolites (NaAlO2, SiO2) and their dispersion in biopolymer poly(lactic acid) (PLA), with a particular interest in the improvement of antibacterial properties, permeability to water vapor, oxygen permeability and mechanical properties. Using two zeolite particles of a different size: micrometric (zeolites) and nanometric (Nanozeolites) sizes, we prepared these composites using the melt mixing process/technique by means of a Brabender mixer. We started by characterizing the morphology of these composite materials using a scanning electronic microscope (SEM) and NanoSIMS microscopies. A good dispersion of nanozeolites is ensured only when a stabilizer (polyethylene glycol (PEG) with M=1000g/mol) is used. Then a comparative study on the physical (gas barrier properties) and mechanical properties (high strain mechanical properties) of these two families of composites has been conducted. It was shown that these two families present almost similar barrier and anti-bacterial properties. The strong point of the nanocomposites is their good mechanical properties (high young modulus and high tensile strength). These mechanical and physical properties of the nanocomposites are ensured only when a PEG of M=1000g/mol is used as stabilizer.

Improvement in antibacterial properties of Ti by electrodeposition of biomimetic Ca–P apatite coat on anodized titania

Titanium metal (Ti) with antibacterial function was successfully developed in the present study by electrodeposition of biomimetic Ca–P coat in simple supersaturated calcium and phosphate solution (SCPS). The electrochemical behavior and corrosion resistance of Ca–P deposited on anodized titanium (AT) have been investigated in SCPS by using electrochemical impedance spectroscopy (EIS). The plate-counting method was used to evaluate the antibacterial performance against Staphylococcus aureus (ATCC6538). In vitro antibacterial activity study indicated a significantly reduced number of bacteria S. aureus on Ca–P/AT plate surface when compared with that on Ti or AT surfaces and the corresponding antibacterial mechanism is discussed. The morphology and chemical structure of different titanium samples were systematically investigated by scanning electron microscope (SEM) and energy dispersive X-ray analysis (EDX). The study confirmed that the antibacterial properties of the samples were related to chemical composition of sample surface.