Antibacterial Activity Of Nanoparticles Research Articles

Spectroscopic and antibacterial activities of cobalt and nickel nanoparticles: a comparative analysis

This study aimed to compare the spectroscopy, morphological, electrocatalytic properties, and antibacterial activities of cobalt nanoparticles (CoNPs) with nickel nanoparticles (NiNPs). Cobalt nanoparticles and NiNPs were prepared via a chemical reduction approach and characterized utilizing transmission electron microscopy (TEM), energy-dispersive X-ray (EDX), and X-ray diffraction (XRD) techniques. The result from XRD and TEM analysis revealed that the synthesized nanoparticles exhibit face-centered cubic with smooth spherical shape, having average particles size of 12 nm (NiNPs) and 18 nm (CoNPs). The electrochemical properties of the nanoparticles were examined via cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) techniques. The CV results showed that GCE-Ni (35.6 μA) has a higher current response compared to GCE-Co (10.5 μA). The EIS analysis revealed that GCE-Ni (1.39 KΩ) has faster electron transport capability compared to GCE-Co (2.99 KΩ) as indicated in their Rct values. The power density of the synthesized nanoparticles was obtained from their "knee" frequency (f°) values, with GCE-Ni (3.16 Hz) having higher f° values compared to GCE-Co (2.00 Hz). The antibacterial activity of the nanoparticles was evaluated against multidrug-resistant Escherichia coli O157, Escherichia coli O177, Salmonella enterica, Staphylococcus aureus, and Vibrio cholerae. The result from the antibacterial study revealed that at low concentrations both CoNPs and NiNPs have significant antibacterial activities against E. coli O157, E. coli O177, S. enterica, S. aureus, and V. cholerae. NiNPs showed better antibacterial activities at low concentrations of 61.5, 61.5, 125, 61.5, and 125 µg/mL compared to CoNPs with minimum inhibitory concentrations of 125, 125, 250, 61.5, and 125 µg/mL against E. coli O157, E. coli O177, S. enterica, S. aureus, and V. cholerae, respectively. These promising antibacterial activities emphasize the potential of CoNPs and NiNPs as effective antibacterial agents, which could aid in the development of novel antibacterial medicines.

In Vitro Investigation of Antibacterial Enhancement Using Silver and Gold Nanoparticles Against Multidrug-resistance Staphylococcus aureus

The aim of this study is to investigate the antibacterial enhancement of silver and gold nanoparticles against multidrug-resistance Staphylococcus. A total of 75 multidrug-resistant S. aureus were isolated from 200 different clinical samples from patients in Arbil, Iraq. All isolates were tested for their resistance against ten different types of antimicrobials. Isolates were treated with silver nanoparticles (AgNPs) and gold nanoparticles (AuNPs) by the disc diffusion method. Treated isolates were tested for their minimum minimum inhibitory concentration (MIC) by using the broth microdilution method. The antibacterial activity of nanoparticles against isolates significantly increased the zone 3.6±36 mm for AuNPs and 1.78±25 mm for AgNPs. All isolates were sensitive to Imipenem, Ceftriaxone, and Ciprofloxacin, whereas highest rate of was seen among Trimethoprim, Azithromycin, Amikacin, Tetracycline, Aztreonam, Pipracycline, and Vancomycin. The fractional inhibitory concentration index (FICI) result revealed that 0.91 was from Azithromycin with AgNPs and 1 from Vancomycin with AgNPs, while the FICI results for AuNPs were 0.94 for Vancomycin with AuNPs, 1 for Imipenem. The synergistic effect between the Imipenem and AgNPs were as follows: the FICI value reached 0.45, and 0.62 Imipenem and AuNPs.

Abatement of microbes and organic pollutants using heterostructural nanocomposites of rice straw CQDs with substituted strontium ferrite

Sustainable use of agricultural waste still remains a challenging task. Herein, we used rice straw as a carbon precursor to prepare carbon quantum dots (CQDs) for photocatalytic applications. Nanocomposites of CQDs with Ti4+ and Mg2+ substituted strontium ferrite (Sr0·4Ti0·4Mg0·2Fe2O4.4) nanoparticles (NPs) in varying w:w ratio was synthesized by ultrasonication method. The successful formation of nanocomposites was confirmed by various microscopic and spectroscopic techniques. The photocatalytic and antibacterial activity of NPs, CQDs and nanocomposites was comparatively evaluated using tetracycline hydrochloride, azure B, Staphylococcus aureus and Escherichia coli as model pollutants. The CQDs-Sr0.4Ti0·4Mg0·2Fe2O4.4 nanocomposite with a w:w ratio of 2:1 showed excellent photocatalytic and antibacterial activity, with the degradation and inactivation efficiency ranging from 97.1% to 99.0% in presence of visible light. The increased specific surface area (117.2 m2/g), and reduction in band gap (2.48 eV–2.09 eV) and decreased photoluminescence intensity of nanocomposites all corroborated these results. The impacting experimental parameters such as catalyst dose, pH and contact time were also examined. Quenching experiments confirmed that hydroxyl radicals (HO∙) radicals and holes (h+) played a vital role in the degradation of pollutants. The kinetics of photodegradation was explained by using the Langmuir-Hinshelwood model. Box-Behnken statistical modelling was used to optimize photocatalytic parameters. Results indicated that the nanocomposite of CQDs with Sr0·4Ti0·4Mg0·2Fe2O4.4 can serve as a promising photocatalyst for the removal of pollutants and microbes.

Green route synthesis of transition metal doped V2O5 nanoparticles, with emerging biomedical applications

In this proposed work we synthesized the pristine V2O5 nanoparticles and Ag (3.2 % (SV-1), 14.5 %, (SV-5) 23.4 % (SV-9), Cd (5.8 % (CV-1), 23.5 % (CV-5), 35.7 % (CV-9)) and Ru doped (4.9 % (RV-1), 20.7 % (RV-5), 32 % (RV-9)) V2O5 nanoparticles using vigna radiata extract. The nanoparticles were characterized by various techniques like UV-DRS, FT-IR, XRD, FE-SEM and HR-TEM. The antibacterial activities of nanoparticles were studied using bacterial strains such as Staphylococcus aures (S.aureus), Streptococcus pneumoniea (S. pneumoniea), Pseudomonas aeruginosae (P. aeruginosae), Klebsiella pneumoniea (K. pneumoniea) and Escherichia coli (E.coli). Among the nanoparticles the potential bacterium growth inhibition of 99 % for S.aureus was observed for CV-5. The binding efficiency of the nanoparticles with the biomolecule BSA was studied by using UV–visible absorption and emission spectral techniques. It was found that there is a binding interaction between them and the binding constant values are in the range from 104 to 105 M−1. The quenching rate constant (kq) value is bigger than the maximum diffusion constant of biomolecules 2.0 x 1010M−1s−1 suggesting that the interaction is static quenching type. In glucose oxidation studies lower potential with a high current density of 440 mA/cm2 occurred for pristine V2O5 NPs.

Antibacterial Activity of ZnO Nanoparticles in a Staphylococcus-aureus-Infected Galleria mellonella Model Is Tuned by Different Apple-Derived Phytocargos.

This research investigates pH changes during the green synthesis of ZnO nanoparticles (NPs) and emphasises its importance in their physicochemical, antibacterial, and biological properties. Varying the synthesis pH from 8 to 12 using "Bravo de Esmolfe" apple extracts neither affected the morphology nor crystallinity of ZnO but impacted NP phytochemical loads. This difference is because alkaline hydrolysis of phytochemicals occurred with increasing pH, resulting in BE-ZnO with distinct phytocargos. To determine the toxicity of BE-ZnO NPs, Galleria mellonella was used as an alternative to non-rodent models. These assays showed no adverse effects on larvae up to a concentration of 200 mg/kg and that NPs excess was relieved by faeces and silk fibres. This was evaluated by utilising fluorescence-lifetime imaging microscopy (FLIM) to track NPs' intrinsic fluorescence. The antibacterial efficacy against Staphylococcus aureus was higher for BE-ZnO12 than for BE-ZnO8; however, a different trend was attained in an in vivo infection model. This result may be related to NPs' residence in larvae haemocytes, modulated by their phytocargos. This research demonstrates, for the first time, the potential of green synthesis to modulate the biosafety and antibacterial activity of NPs in an advanced G. mellonella infection model. These findings support future strategies to overcome antimicrobial resistance by utilizing distinct phytocargos to modulate NPs' action over time.

Nano-silver-modified polyphosphazene nanoparticles with different morphologies: Design, synthesis, and evaluation of antibacterial activity

Drug-resistant bacteria present a severe threat to public health, emphasizing the importance of developing broad-spectrum antibacterial agents that are free from drug resistance. Among silver-based antibacterial agents, nano-silver has been found to exhibit the most promising and comprehensive performance. The exploration of the antibacterial capacity and morphological changes of silver nanoparticles (AgNPs) could offer a starting point for the development of safe and efficient antibacterial agents. In this study, three types of nano-silver-modified polyphosphazene (PRV) nanoparticles with different morphologies were synthesized using precipitation polymerization. These nanoparticles were characterized using various techniques, including Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and thermogravimetric analysis (TGA). The antibacterial activity of these nanoparticles against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) was assessed using minimum inhibitory concentration (MIC)/minimum bactericidal concentration (MBC) tests and inverted fluorescence microscopy. Our results revealed that the antibacterial activity of silver nanoparticles can vary significantly depending on their immobilized form. Ag@PRV Strawberry-like nanoparticles (NPs) exhibited higher antibacterial activity compared to Ag@PRV Yolk-Shell NPs and Ag@PRV Cable-like nanofibers (NFs). Notably, all three types of synthesized nanoparticles demonstrated a stronger bactericidal effect on Gram-positive bacteria than Gram-negative bacteria. Live/dead bacterial staining and scanning electron microscopy demonstrated that silver can kill bacteria by altering the permeability of their cell membranes. These findings offer valuable insights for designing and practically applying new silver-based antibacterial agents in the future.

Pharmacological assessment of Co3O4, CuO, NiO and ZnO nanoparticles via antibacterial, anti-biofilm and anti-quorum sensing activities.

Infectious diseases have risen dramatically as a result of the resistance of many common antibiotics. Nanotechnology provides a new avenue of investigation for the development of antimicrobial agents that effectively combat infection. The combined effects of metal-based nanoparticles (NPs) are known to have intense antibacterial activities. However, a comprehensive analysis of some NPs regarding these activities is still unavailable. This study uses the aqueous chemical growth method to synthesize Co3O4, CuO, NiO and ZnO NPs. The prepared materials were characterized by scanning electron microscopy, transmission electron microscopy and X-ray diffraction techniques. The antibacterial activities of NPs were tested against Gram-positive and Gram-negative bacteria using the microdilution method, such as the minimum inhibitory concentration (MIC) method. The best MIC value among all the metal oxide NPs was 0.63 against Staphylococcus epidermidis ATCC12228 through ZnO NPs. The other metal oxide NPs also showed satisfactory MIC values against different test bacteria. In addition, the biofilm inhibition and antiquorum sensing activities of NPs were also examined. The present study presents a novel approach for the relative analysis of metal-based NPs in antimicrobial studies, demonstrating their potential for bacteria removal from water and wastewater.

Optical characteristics and bacterial-resistance ability of PVA/ZnO nanocomposites

Poly(vinyl alcohol) (PVA) thin films with different amounts of zinc oxide (ZnO) nanoparticles (NPs) (0.001, 0.002, 0.003, 0.004 and 0.005 ​g) were prepared using the casting method. The structural characteristics of the PVA polymer, ZnONPs and the mixture of polymer and ZnO NPs with a particle size of 80 ​nm have been studied using X-ray diffraction, Scanning Electron Microscopy and Fourier Transform Infrared spectroscopy. The optical characteristics of PVA/ZnO nanocomposites were studied in the wavelength range of 200–700 ​nm. According to experimental research, adding more ZnONPs to nanocomposites improves the PVA polymer's absorbance, absorption coefficient, extinction coefficient, refractive index and real and imaginary dielectric constants. As the amount of ZnONPs increases, the transmittance and energy gap of the PVA polymer decrease. Research on the antibacterial activity of these nanocomposites was conducted using Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli, Klebsiella quasipneumoniae subsp. Similipneumoniae as pathogen microorganisms. According to the findings, the antibacterial activity of NPs is greatly influenced by their chemical make-up and form. Moreover, increasing the amount of ZnO in the composites causes an increase in antibacterial activity.

Antibacterial activity of nanoparticles and nanomaterials: a possible weapon in the fight against healthcare-associated infections.

Healthcare-associated infections are a serious threat in terms of morbidity and mortality for all patients receiving healthcare. The problem is aggravated by the increasingly widespread phenomenon of antibiotic resistance, with some microorganisms now resistant to all or almost all the currently available antibiotics. Nanomaterials are compounds used by many different industrial fields and they are currently studied for their intrinsic antimicrobial properties. To date, many researchers have considered using many different nanoparticles and nanomaterials to produce surfaces and medical devices with intrinsic antimicrobial features. Many compounds have shown very interesting and effective antimicrobial capacities and could be used, in the future, to manufacture new hospital surfaces and medical devices. However, many studies have to be carried out to evaluate the effective potential use of these compounds. The aim of this paper is to review the main literature regarding this topic, focusing on the main types of nanoparticles and nanomaterials studied for this purpose.

The role of TiO2 photocatalyst in degradation of halogenated phenols: Experimental, DFT and antibacterial study

Degradation of industrial pollutants 4-chlorophenol and 4-bromophenol by heterogeneous photocatalysis using TiO2 nanoparticles of different sizes and allotropes was investigated. Physicochemical properties of a wide range of TiO2 nanoparticles were correlated with their photocatalytic activity. The increase in anatase particle size led to an enhancement of the halophenols degradation rate, oppositely to rutile. EPR measurements and experiments using radical scavenger showed that depending on anatase nanoparticles size, different reactive species dominated halophenols degradation. Based on DFT modeling, alternative degradation pathways were proposed, leading to hydroxylation of halophenol aromatic ring or to direct decarboxylation. Antibacterial activity of nanoparticles, 4-chlorophenol and degradation intermediates was investigated. Changes in toxicity during the photocatalytic process were evaluated. Our results demonstrate that not only crystalline form and/or morphology of the photocatalyst, but also other properties as well as treatment duration are important parameters in its performance and should be considered in the development of photocatalytic applications.

Evaluation of the Antibacterial Properties of Iron Oxide, Polyethylene Glycol, and Gentamicin Conjugated Nanoparticles against Some Multidrug-Resistant Bacteria.

Antibacterial resistance is observed as a public health issue around the world. Every day, new resistance mechanisms appear and spread over the world. For that reason, it is imperative to improve the treatment schemes that have been developed to treat infections caused by wound infections, for instance, Staphylococcus epidermidis (S. epidermidis), Proteus mirabilis (P. mirabilis), and Acinetobacter baumannii (A. baumannii). In this case, we proposed a method that involves mixing the Gentamicin (Gen) with iron oxide nanoparticles (Fe3O4 NPs) and a polymer (polyethylene glycol (PEG)) with Fe3O4 NPs. X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), energy dispersive X-ray (EDX), scanning electron microscope (SEM), and transmission electron microscope (TEM) were used to characterize Fe3O4 NPs. Zeta potential and dynamic light scattering (DLS) were also assessed. The antibacterial activity of Fe3O4 NPs, Fe3O4 NPs+PEG, Fe3O4 NPs+Gen, and Fe3O4 NPs+PEG+Gen composites was investigated. The results showed a significant improvement in the antibacterial activity of nanoparticles against bacterial isolates, especially for the Fe3O4 NPs+PEG+Gen as the diameter of the inhibition zone reached 26.33 ± 0.57 mm for A. baumannii, 25.66 ± 0.57 mm for P. mirabilis, and 23.66 ± 0.57 mm for S. epidermidis. The Fe3O4 NPs, Fe3O4 NPs+PEG, Fe3O4+Gen, and Fe3O4+PEG+Gen also showed effectiveness against the biofilm produced by these isolated bacteria. The minimum inhibitory concentration (MIC) of Fe3O4 NPs for S. epidermidis was 25 µg mL−1 and for P. mirabilis and A. baumannii was 50 µg mL−1. The findings suggest that the prepared nanoparticles could be potential therapeutic options for treating wound infections caused by S. epidermidis, P. mirabilis, and A. baumannii.

Probing the effect of Ni, Co and Fe doping concentrations on the antibacterial behaviors of MgO nanoparticles

The divalent transition metal ions (Ni, Co, and Fe)-doped MgO nanoparticles were synthesized via the sol–gel method. X-ray diffraction showed the MgO pure, single cubic phase of samples at 600 °C. Field emission electron microscope showed the uniform spherical shape of samples. The magnetic behavior of Ni, Co, Fe-doped MgO system were varied with Ni, Co, Fe content (0.00, 0.01, 0.03, 0.05, 0.07). The magnetic nature of pure had changed from paramagnetic to ferromagnetic. The number of oxygen vacancies increases with increasing amounts of dopant ions that lead to an ionic charge imbalance between Ni2+/Co2+/Fe2+ and Mg2+, leading to increase magnetic properties of the samples. The magnetic nature of prepared samples makes them suitable for biomedical applications. A comparative study of the antibacterial activity of nanoparticles against the Gram-negative (E. coli) and Gram-positive bacteria (S. aureus) was performed by disc diffusion, pour plate techniques, and study surface morphology of untreated and treated bacterial cell wall. An investigation of the antibacterial activity of doped MgO nanoparticles reveals that the doped MgO nanoparticles show effective antibacterial activity against the Gram-negative (E. coli) and Gram-positive (S. aureus) bacterium. The minimum inhibitory concentration of the synthesized nanoparticles against microorganisms was recorded with 40 μg/ml, while the maximum inhibitory concentration was observed with 80 μg/ml. At a concentration of 80 μg/ml, the complete growth inhibition of the E. coli was achieved with 7% Co-doped MgO and 7% Fe-doped MgO, while bacterial growth of S. aureus was inhibited by 100% in the presence of 7% Fe-doped MgO. The present work is promising for using nanomaterials as a novel antibiotic instead of the conventional antibiotics for the treatment of infectious diseases which are caused by tested bacteria.

Antibacterial Study of LaAlO3:Dy3+: Bi3+ Nanoparticles Synthesized by Modified Combustion Technique

Environmental application for the rare earth dysprosium ion doped and bismuth ion codoped lanthanum aluminate nanomaterials were synthesized using modified combustion technique. Blend of sugar and of E-tirucalli latex extract were used as fuels for the combustion method. The prepared materials were characterized for their size and morphology by analytical techniques. The antibacterial activity of nanoparticles was evaluated against four bacterial by disc diffusion method. Significant activity was observed in 30 µg/ml against Pseudomonas aeruginosa.

Multifunctional Tetracycline-Loaded Silica-Coated Core–Shell Magnetic Nanoparticles: Antibacterial, Antibiofilm, and Cytotoxic Activities

In the current study, the physicochemical and biological properties of tetracycline-loaded core-shell nanoparticles (Tet/Ni0.5Co0.5Fe2O4/SiO2 and Tet/CoFe2O4/SiO2) were investigated. The antibacterial activity of nanoparticles alone and in combination with tetracycline was investigated against a number of Gram-positive and Gram-negative bacteria for determining minimum inhibitory concentration (MIC) values. The MIC of Tet/Ni0.5Co0.5Fe2O4/SiO2 nanoparticles turned out to be significantly higher than that of Tet/CoFe2O4/SiO2 nanoparticles. Furthermore, Tet/Ni0.5Co0.5Fe2O4/SiO2 nanoparticles exhibited potent antibiofilm activity against pathogenic bacteria compared to Tet/CoFe2O4/SiO2 nanoparticles. The drug delivery potential of both carriers was assessed in vitro up to 124 h at different pH levels and it was found that the drug release rate was increased in acidic conditions. The cytotoxicity of nanoparticles was evaluated against a skin cancer cell line (melanoma A375) and a normal cell line (HFF). Our findings showed that Tet/Ni0.5Co0.5Fe2O4/SiO2 had greater cytotoxicity than CoFe2O4/SiO2 against the A375 cell line, whereas both synthesized nanoparticles had no significant cytotoxic effects on the normal cell line. Nonetheless, the biocompatibility of nanoparticles was assessed in vivo and the interaction of nanoparticles with the kidney was scrutinized up to 14 days. The overall results of the present study implied that the synthesized multifunctional magnetic nanoparticles with drug delivery potential, anticancer activity, and antibacterial activity are promising for biomedical applications.

Dual-Layered Approach of Ovine Collagen-Gelatin/Cellulose Hybrid Biomatrix Containing Graphene Oxide-Silver Nanoparticles for Cutaneous Wound Healing: Fabrication, Physicochemical, Cytotoxicity and Antibacterial Characterisation.

Tissue engineering products have grown rapidly as an alternative solution available for chronic wound and burn treatment. However, some drawbacks include additional procedures and a lack of antibacterial properties that can impair wound healing, which are issues that need to be tackled effectively for better wound recovery. This study aimed to develop a functionalized dual-layered hybrid biomatrix composed of collagen sponge (bottom layer) to facilitate cell proliferation and adhesion and gelatin/cellulose hydrogel (outer layer) incorporated with graphene oxide and silver nanoparticles (GC-GO/AgNP) to prevent possible external infections post-implantation. The bilayer hybrid scaffold was crosslinked with 0.1% (w/v) genipin for 6 h followed by advanced freeze-drying technology. Various characterisation parameters were employed to investigate the microstructure, biodegradability, surface wettability, nanoparticles antibacterial activity, mechanical strength, and biocompatibility of the bilayer bioscaffold towards human skin cells. The bilayer bioscaffold exhibited favourable results for wound healing applications as it demonstrated good water uptake (1702.12 ± 161.11%), slow rate of biodegradation (0.13 ± 0.12 mg/h), and reasonable water vapour transmission rate (800.00 ± 65.85 gm−2 h−1) due to its porosity (84.83 ± 4.48%). The biomatrix was also found to possess hydrophobic properties (48.97 ± 3.68°), ideal for cell attachment and high mechanical strength. Moreover, the hybrid GO-AgNP promoted antibacterial properties via the disk diffusion method. Finally, biomatrix unravelled good cellular compatibility with human dermal fibroblasts (>90%). Therefore, the fabricated bilayer scaffold could be a potential candidate for skin wound healing application.

Biosynthesis of Silver nanoparticles using Trichosporon asahii and study their antibacterial and synergism effects

Nanoparticles (NPs) often have strong antibacterial properties to treat a variety of infections, but their high biotoxicity prevents them from being used directly. The biosynthesis of NPs, as well as their capping/conjugation with natural biopolymers, can improve NPs stability and reduce toxicity. Without using any additional chemical processes, Trichosporon asahii was used to directly synthesize silver nanoparticles (AgNPs) by extracellular mechanism. Physical and chemical evaluations such as (solution color change, and UV spectrophotometer), validated the formation of nanoparticles. The AgNPs had similar powerful bactericidal effects against Gram positive (Staphylococcus aureus, Enterococcus Faecalis, Bacillus cereus) and Gram negative (Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumonia). The goal of this study is to evaluate the efficiency of silver nanoparticles antibacterial activity which produced by Trichosporon asahii and use as alternatives to antibiotics

The potential of surface nano-engineering in characteristics of cobalt-based nanoparticles and biointerface interaction with prokaryotic and human cells

Cobalt-based nanoparticles (CBNPs) have recently received great attention in biomedical studies; however, the possible biotoxicity of these nanoparticles (NPs) has remained a foremost concern that should be addressed. As surface functionalization is one of the helpful proposed solutions, we aimed to apply Lipoamino acids (LAAs) as a coating agent to improve biocompatibility. To this purpose, cobalt oxide, cobalt ferrite, and iron oxide nanoparticles (IONs) were synthesized with and without 2-amino-hexadecanoic acid coating to assess the impacts of LAA coating on characteristics and biocompatibility of CBNPs in human cells and compare with IONs, a widely used magnetic NPs in biomedicine. Antibacterial activities of NPs were evaluated against four Gram-negative and Gram-positive bacteria species to assess their biointerface interaction with prokaryotic cells. In addition, the antibacterial activities of synthesized NPs were compared to silver NPs, one of the widely used antimicrobial NPs and standard antibiotics (ampicillin). The structural characteristics properties of NPs were analyzed using TEM, FE-SEM, EDS, FTIR, XRD, and VSM. These NPs exhibited sphere-like to polygon-like morphology with desirable mean size. CBNPs displayed dose-dependent cytotoxicity and antimicrobial activities against human cell lines and all tested microbial species, as well as more cytotoxicity and bacterial inhibition compared to IONs. Besides, the results revealed that LAA coating could significantly improve the biocompatibility and antibacterial activity of NPs while impacting magnetic properties. To sum up, it seems that surface functionalization could provide more potent tools for bioapplications with improving biocompatibility and bacterial inhibition of CBNPs, though; further studies are needed in this regard.

Antibactirial activity of Copper oxide Nano particles against gram positive and negative bacterial strain synthesized by precipitation Techniqe

This work was carried out to investigate the antibacterial activity of CuO nanoparticles (CuONPs), which were produced by synthetic methods of the precipitation technique of the precursor material copper acetate and sodium hydroxide as reducing agents. The purity of the nanoparticles was confirmed by various characterizations. Techniques including X-ray diffraction, Scanning Electron Microscopy (SEM), Ultraviolet (UV), EDAX. The antibacterial activity of nanoparticles was examined with various microorganisms from Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, Klebsiella pneumonia.

Enhanced Antibacterial Activity of Doxycycline and Rifampicin Combination Loaded in Nanoparticles against Intracellular Brucella abortus

Brucellosis is a zoonotic disease that is prevalent in livestock animals. The bacteria reside inside the macrophage cells of the host. The WHO has endorseda combination treatment therapy for brucellosis against the conventional monotherapy to avoid relapse and resistance. Therefore, we developed nanoparticles incorporating doxycycline and rifampicin in combination. The aim of the study is to develop polymeric nanoparticles incorporating doxycycline as well as rifampicin and investigate the antibacterial activity of nanoparticles in U937 human macrophage cells infected with B. abortus. Polymeric nanoparticles were developed by the emulsion-solvent diffusion method, and characterization was performed. The nanoparticles with high entrapment efficiency of both the drugs were developed successfully. Scanning electron microscopy revealed a spherical morphology with a size ranging ~450nm, which can be easily engulfed by the macrophages. Zeta potential confirmed the colloidal stability. Differential scanning calorimetry and X-ray diffraction suggested amorphization of doxycycline and rifampicin in nanoparticles. Fourier transfer infrared spectroscopy could not confirm the interaction of drugs with AOT. In vitro haemolysis study confirmed the safety of nanoparticles (<10%) for IV administration. Further, nanoparticles revealed the sustained release of both drugs, which followed diffusion kinetics. Nanoparticles were found stable for 6 months as per WHO guidelines. The internalization study revealed nanoparticles could be easily uptaken by U-937 human macrophage cells. The efficacy study demonstrated significantly high antibacterial activity of nanoparticles as compared to free drug solution in U937 human macrophages cells infected with Brucella abortus. It can be concluded that the developed nanoparticles entrapping doxycycline and rifampicin combination can be considered as a promising delivery system for enhancing the antibacterial activity against Brucella abortus.

Particle specific physical and chemical effects on antibacterial activities: A comparative study involving gold nanostars, nanorods and nanospheres

The present report compares the antibacterial properties of unique (sphere+rod)-shaped gold nanostar with its structural components, i.e., gold nanorods and nanosphere. Gold nanostars, nanorods, and nanospheres have been synthesized using literature reported protocols. Clinical isolates of gram-negative E. coli and gram-positive S. aureus bacteria have been used as model pathogens for the antibacterial studies. The antibacterial activities of the nanoparticles have been assessed using various techniques. To compare the antimicrobial activity of the nanoparticles, we have investigated the effects of varying gold concentrations of different nanoparticles on bacterial growth kinetics. The impacts of the leached/residual gold ions and the surface capping agent and charge of the particles on the antibacterial activity have also been assessed. Studies of the nanoparticle’s dose and exposure time show the highest antibacterial activity for nanostars and lowest for nanospheres for a given quantity of gold. Bradford’s Reagent Assay and confocal fluorescent microscopy studies confirm the trend of the particle-specific antibacterial activities. SEM/TEM and DNA extraction studies show that the bactericidal activities involve a combination of effects like the destruction of cell membrane, fragmentation of bacterial DNA, internalization of particles, etc. To assess the antibacterial impacts of the amount of leached/residual gold ions, their concentrations have been determined by inductively coupled plasma - optical emission (ICP-OES) and mass (ICP-MS) spectroscopic studies as well as the effects of the added gold ions have been studied. No discernible effects have been observed due to the variation in the leached/residual gold ions amount. The DCHF-DA fluorescence assay has been employed to determine the levels of reactive oxygen species (ROS) produced by different nanoparticle systems, which corresponds to the trend in antibacterial activities observed. The nature and magnitude of the surface charge have been determined by zeta potential measurements. Analyses of the impacts of various parameters/factors like gold ions, capping agents, surface charges, ROS levels, etc., show that the antibacterial activities of the gold nanoparticles of different morphology arise from both morphology-specific physical and chemical effects of the gold nanoparticles.