Evaluation Of Antibacterial Activity Research Articles

Green Synthesis, Characterization of Copper Sulfide Nanoparticles and Antibacterial Activity Evaluation

This study focused on the eco-friendly and economical synthesis of copper sulfide nanoparticles at certain temperatures using myrtle leaf extract. Green synthesis methods are mostly considered to be safe and efficient in the nanoparticle synthesis field. The nanoparticles were characterized using FT-IR, AFM, UV-visible spectrophotometer, FESEM with EDX, and XRD. where the crystal size in XRD was 21.4 nm. The antibacterial properties of CuS nanoparticles were evaluated against two bacterial strains, namely, Staphylococcus aureus and Escherichia coli, using various concentrations. The Minimum Inhibitory Concentration (MIC) was determined for both bacteria at a range of CuS NPs conc. from 0.5229 × 10-1 M to 0.3268 × 10-2 M.

Evaluation of Antibacterial Activity of Solvent Extracts of Spirulina fusiformis against Pathogenic Bacterial Strains

This study explores the antibacterial properties of Spirulina fusiformis, a blue-green alga with significant dietary and medicinal value. Spirulina is recognized globally for its nutrient-rich composition and potential therapeutic applications. With antibiotic resistance emerging as a serious global health concern, algae-derived bioactive compounds offer a promising, natural alternative to traditional antibiotics due to their non-toxic profile and effectiveness against pathogenic bacteria. The antibacterial activity of S. fusiformis was assessed using various solvent extracts, including petroleum ether, benzene, ethyl acetate, methanol, and ethanol, tested against twelve bacterial strains, including Bacillus thuringiensis, Staphylococcus aureus, Streptococcus pyogenes, and Escherichia coli, using the well diffusion method. Results showed that the ethanol extract of S. fusiformis exhibited the highest antibacterial activity, inhibiting all tested bacteria, with the greatest zones of inhibition observed against Streptococcus pyogenes (17 mm) and Bacillus thuringiensis (16 mm). The presence of some significant antimicrobial compounds present in the ethanol extract. These findings support the use of Spirulina fusiformis as a natural antibacterial agent and underline its potential in developing alternative therapeutic strategies for combating antibiotic-resistant pathogens.

Chemical Composition, In Silico Investigations and Evaluation of Antifungal, Antibacterial, Insecticidal and Repellent Activities of Eucalyptus camaldulensis Dehn. Leaf Essential Oil from ALGERIA.

This study investigated the phytochemical profile and evaluated the antimicrobial and insecticidal properties of Eucalyptus camaldulensis Dehn. essential oil (EC-EO) from Algeria, using in vitro and in silico approaches. The yield of EC-EO was 0.27%, with gas chromatography-mass spectrometry (GC-MS) revealing spathulenol (58.24%), cryptone (17.22%), and o-cymene (15.53%) as the major compounds. EC-EO exhibited notable antibacterial activity, particularly against Salmonella typhimurium (14 ± 1.00 mm) and Staphylococcus aureus (14.5 ± 0.50 mm). It also showed effective antifungal activity against Penicillium sp. (11.5 ± 0.49 mm), Candida albicans (11.2 ± 0.29 mm), and Aspergillus fumigatus (9.8 ± 0.27 mm). Insecticidal assays against Tribolium castaneum were conducted using contact toxicity, fumigation toxicity, and repellent activity methods. The median lethal concentration (LC50) for contact toxicity was 0.011 μL/insect after 72 h, while the fumigation test had an LC50 of 122.29 μL/L air. Repellent activity tests showed percentage repellency (PR) values exceeding 80% after 6 h. The molecular geometry and electronic properties of the main compounds were studied using density functional theory (DFT) calculations. In addition, the interaction mode and binding affinity of these molecules with three key enzymes involved in antimicrobial activity, DNA gyrase, dihydrofolate reductase (DHFR) and Tyrosyl-tRNA synthetase (TyrRS), were explored by molecular docking.

Formation and Preparation of Herbal Hair Tonic

Today, people are keenly interested in hair preparations and conditioner materials that includes shampoos, hair tonic, and conditioner formulation with herbal extracts. Hair tonic is the product which is used in styling hair. The objective of the present study involved the preparation of herbal hair tonic through the use of jojoba, tulsi, and coconut oil and its evaluation for antifungal and antibacterial activity. The final preparation of these ingredients is formulated in batches with change in concentration. Each formulation is tested for antibacterial and antifungal activity. The formulation of different concentrations was characterized for proximate analysis including moisture content, total ash, acid insoluble ash, water soluble ash, water insoluble ash, sulphated ash. It means for antifungal and antibacterial activity the formulation gives good results, the formulation having good consistency, good spread ability, homogeneity, appearance, and pH.

Synthesis, Characterization and Antibacterial Activity Evaluation of CuO NPs and B-CuO NPs Obtained from Livistona Chinensis Leaf Extract.

Nanoparticles (NPs) exhibit fascinating size-dependent chemical and physical characteristics that make them useful for a variety of applications. The present paper reports the green synthesis of CuO NPs and B-doped CuO NPs (B-CuO NPs) from Livistona chinensis leaf extract. Not much work has been reported on the use of the plant extract for the fabrication of NPs, particularly those of Cu and its doped counterparts. Various spectroscopic techniques were used to characterize the synthesized NPs. In the FT-IR spectra, peaks obtained at 504 cm-1 to 600 cm-1 were due to Cu-O vibrations. The energy dispersive X-ray analysis (EDX) spectra confirmed the CuO NPs' composition and B's presence inside the NPs. The peak pattern in the X-ray diffraction (XRD) spectrum confirmed the crystalline and monoclinic phases of the NPs. The average crystalline size of CuO NPs and B-CuO NPs was 19.56 nm and 17.30 nm respectively. The CuO and B-CuO NPs were tested against three Gram-positive bacterial strains namely Bacillus subtilis, Micrococcus luteus, and Staphylococcus aureus and three Gram-negative Escherichia coli, Salmonella abony, and Pseudomonas aeruginosa through Agar well diffusion method and it was found that CuO NPs showed higher activity than B-CuO NPs. Gentamicin was used as the positive control. The antibacterial activity may be due to the cell wall disruption by induction of innate and adaptive host immune response, generating toxic reactive oxygen species (ROS), and stimulating intracellular effects.

Evaluation of Antibacterial Activity of Milk Peptides Released during the Growth of Lactobacilli in Milk

The present study is carried out to evaluate the antibacterial peptides released during the growth of lactobacilli in milk. Among 8 isolates of lactobacilli and yoghurt cultures used for study, the yoghurt culture released the maximum quantity of peptides (90 ± 1.25 µg/ml). When tested for antibacterial activity only yoghurt culture filtrate showed the antibacterial potential. Further, yoghurt culture lysate was prepared, which was used to treat the milk to bring in proteolysis. The supernatant obtained after centrifugation of this treated milk was used to partially purify peptides by gel filtration using Sephadex G-50. One of the three fractions (F2) showed antibacterial activity against test organisms, E. coli, Salmonella sp. and Shigella dysentriae. The peptide fraction was incorporated into curd samples inoculated with different lactic cultures and spiked with E. coli to determine antibacterial activity. It was found that peptide showed a bacteriostatic effect on E. coli, and the viable count of it was almost reduced by two log cycles when compared with the control.

Evaluation of Antibacterial Activity of Bismuth Ferrites Nanoparticles in the Inhibition of E. Coli and S. Aureus Bacteria.

In this work, bismuth ferrites (BFO) nanoparticles were produced in the form of using sol-gel technique, followed by annealing in a tube furnace in temperatures from 400 °C to 650 °C. X-ray diffraction (XRD) results showed the formation of small sizes nanoparticles (NPs) with high purity. Structural analysis displayed that annealing at 600 °C could make BFO NPs be fitted to rhombohedral space group (R3c), with small quantity of spurious phases. The sizes of the BFO nanoparticles determined by transmission electron microscopy (HRTEM) are between 50 to 100 nm. To evaluate the efficiency of BFO in antimicrobial susceptibility tests, the nanoparticles were dispersed through cand tested agar diffusion method and dilution in a 96 well plate using a Gram-positive strains (Staphylococcus aureus) and Gram negative strain (Escherichia coli). The antibacterial activity of the BFO NPs was tested at concentrations of 2 mg/mL with MIC greater than 60 μg/mL for both bacteria.

Evaluation of Antibacterial Activity and Synergistic Interaction between Punica granatum peels and Synthetic Antibiotics on Multidrug-Resistant Bacteria

IntroductionAntibiotic resistance threatens global health, necessitating the development of new antimicrobial medications. Novel drugs can reverse drug resistance and revitalize the antibiotic arsenal. Therefore, this study aimed to evaluate the synergistic antibacterial effect of Punica granatum (P. granatum) extract and antibiotics against multidrug-resistant bacteria (MDR). MethodsPreliminary susceptibility profiling of the antibiotics, the antibacterial activity of the extract, and synergistic interactions between the extract and the three antibiotics were conducted using well diffusion and micro-broth dilution assays with resazurin dye. The inhibition zones (IZs), minimum inhibitory concentrations (MICs), and Fractional Inhibition Concentration Index (FICI) were determined. The data were analyzed using statistical software program (SPSS 26). ResultsThe bacterial isolates exhibited resistance to all antibiotics, except E. coli and P. aeruginosa were sensitive to Ciprofloxacin. P. granatum extract demonstrated an inhibitory effect on all tested bacteria. The FICI values for MDR strains ranged from (0.12 to 0.53), and the best synergistic effect was observed when Augmentin and Ciprofloxacin were combined against these strains. The FICI indices for the combination of P. granatum and Azithromycin ranged from (0.12 to 0.53). ConclusionThis study identified P. granatum extract as a potential adjunctive therapy to antibiotics for the treatment of multidrug-resistant bacteria.

Dual drug molecular salt of antibacterial: Formulation, physicochemical properties study, theoretical calculations and evaluation of antibacterial activity

A molecular salt combined with the fluoroquinolone antibacterial gatifloxacin (GAT) and the sulfonamides antibacterial sulfamerazine (SMZ) is designed and synthesized successfully, which is the first report of the dual-drug cocrystallization of gatifloxacin. The precise structure of the acquired molecule salt GAT-SMZ has been characterized via single crystal X-ray diffraction and other techniques. Single crystal diffraction analysis displays that due to the transfer of protons from SMZ to GAT, the molecular salt of GAT-SMZ is formed, and the supramolecular network is dominated by charge-assisted one-dimensional hydrogen bond chain and two-dimensional accumulation layer in the crystal. Such structural feature endows molecular salt with superior physicochemical properties, including enhanced solubility and permeability. More importantly, the superior pharmaceutical performances of the dual-drug salt resulted in enhanced antibacterial activity against the tested strains. These observations are strongly supported by theoretical studies based on Hirshfeld surface and molecular docking analyses. Thus, this contribution not only highlights the validity of combining theory with experiment to drive the problem of physicochemical properties of drugs through co-crystallization methods, but also fills in the previous studies gatifloxacin dual-drug salt synergistic antibacterial research blank.

Evaluation of antibacterial activity of ethanolic extracts of Ruta chalepensis, Hippocratea excelsa, Litsea glaucescens and Waltheria americana against methicillin-resistant Staphylococcus aureus

Evaluation of antibacterial activity of ethanolic extracts of Ruta chalepensis, Hippocratea excelsa, Litsea glaucescens and Waltheria americana against methicillin-resistant Staphylococcus aureus

LC-MS guided discovery of a new type of abyssomicin, glycoabyssomicin A, from a deep-sea derived Streptomyces

Glycoabyssomicin A (1), a new type of abyssomicin containing a sugar unit, was isolated from the deep-sea derived Streptomyces koyangensis SCSIO 5802 guided by LC-MS. The structure of 1 was elucidated by HR-ESI-MS, 1D-NMR (1H,13C NMR), 2D-NMR (HSQC, COSY, HMBC, NOESY), and TFA hydrolysis and acetylation reactions. In the antibacterial activities evaluation against a series of gram-positive and gram-negative bacteria, it showed inactive at the concentration of 10 μg per filter paper disc. This finding would broaden the way for discovery of more lead compounds of abyssomicins.

Synthesis of Luminescent Copper Nanoparticles Using Couroupita guianensis Flower Extract: Evaluation of Antibacterial and Anticancer Activities.

The biosynthesis of nanoparticles is a crucial research area aimed at developing innovative, cost-effective, and eco-friendly synthesis techniques for various applications. Herein, we synthesized copper oxide nanoparticles (CuNPs) using Couroupita guianensis flower extract via a simple green synthesis method. These green CuNPs demonstrate promising antimicrobial activity and anticancer activity against A549 nonsmall cell lung cancer (NSCLC) cells. We comprehensively characterized the CuNPs using UV spectrum, XRD, FTIR, SEM, and EDS analyses. The antibacterial and anticancerous performance is attributed to their spherical-like morphology, which enhances effective interaction with bacterial and cancer cells. Moreover, CuNPs proved effective in inactivating Escherichia coli, achieving 2%, 52%, and 99% inactivation at 0, 30, and 60 min, respectively, and Listeria monocytogenes, achieving 1%, 48%, and 98% inactivation at 0, 30, and 60 min, respectively, under visible light. Furthermore, the CuNPs exhibited significant anticancer activity against A549 NSCLC cells, achieving cell viability reductions of 10%, 30%, 50%, 70%, 83%, and 91% at concentrations of 25, 50, 100, 150, 200, and 250 μg/mL, respectively. The green synthesized CuNPs demonstrate their potential in biomedical applications.

Influence of the extraction method on functional properties of commercial snail secretion filtrates

Snail secretion is a complex mixture of several components, including proteins, glycoproteins, mucopolysaccharides and smaller molecules. Its growing use in nutraceutical, cosmetic and biomedical applications, as well as a component of edible and green packaging to replace chemical plasticizer, implies more affordable and sustainable extraction methods. We chose four extracts obtained from Cornu aspersum snails, different by origin, extraction medium (namely, citric acid, lactic acid or none) and additives and we performed a series of characterizations including the SDS-page, the measure of pH and density, the evaluation of dry matter and of protein content, supported by structural determinations by means of UV-visible and infrared spectroscopy, X-Rays diffraction and thermogravimetric measurements. Biological assays comprising evaluation of cytotoxicity and antibacterial activity were also carried out. All the tests were performed both on the as received snail filtrates and on the samples after proper dialysis to remove preservatives added by manufacturers. The obtained results put into evidence that the properties and composition of the final extract are strongly influenced by the collection method, that can be relevant for the proper use of snail filtrate in specific applications.

Regioselective Oxidation of Tetrahydronaphthalenes to α-Tetralone Derivatives Using DDQ as Oxidizing Agent: Synthesis and Evaluation of Antibacterial and Antifungal Activities.

An easy and efficient approach for the synthesis of highly regioselective functionalized dihydronaphthalen-1(2H)-one family of α-tetralones from functionalized tetralone precursors which derived from Morita-Baylis-Hillman (MBH) adducts as starting substrates has been developed. The target dihydronaphthalen-1(2H)-ones are obtained through the oxidation of tetrahydronaphthalenes (THN) using DDQ as the oxidizing agent, conducted in aqueous acetic acid at reflux conditions. The yields obtained ranged from 90 to 98%. The resulting dihydronaphthalen-1(2H)-ones were evaluated for their in vitro antibacterial activity against nine Gram-positive and six Gram-negative strains. Additionally, their antifungal properties were assessed against three fungal pathogens by using the microdilution method and Biolog Phenotype Microarrays technology. Remarkably, the synthesized dihydronaphthalen-1(2H)-ones exhibited good antibacterial activity when compared to reference drugs such as vancomycin and ampicillin. Similarly, their antifungal activity is comparable to the effectiveness of the reference drugs cycloheximide and fluconazole.

Evaluation of Antibacterial Activities of Clove Bud Oil and Extract on Bacterial Isolates from Dental Caries

Dental caries remains one of the most prevalent oral health issues worldwide, primarily caused by bacterial activity w ithin the oral cavity. This study investigates the antibacterial activities of clove oil bud against bacteria associated with dental caries. The clove buds were collected, identified, and processed for ethanol extraction of bioactive compounds. Also, 30 samples of dental caries were obtained using swab sticks and cultured on nutrient agar, MacConkey agar, and Mannitol salt agar, then incubated for 24 hours and identified using biochemical tests and molecular analysis. Qualitative and quantitative phytochemical analysis confirmed the presence of alkaloids (5.033%), saponins (3.50%), flavonoids (0.407%), phenols (0.4545%), tannins (5.227%), and glycosides (2.1285%) in the ethanol extract, while the clove oil contained saponins (8.70%) and a small amount of glycosides (0.0375%). The extracted compounds underwent Gas Chromatography-Mass Spectrometry (GC-MS) analysis, which identified key constituents such as eugenol, Caryophyllene oxide, and 9,12-Octadecadienoic acid. The characterization of the clove oil revealed a density of 0.86 g/cm³, viscosity of 113.59 mm²/s, refractive index of ≥36% Brix, saponification value of 39.19 mg KOH, iodine value of 21.488 g/ml, peroxide value of 13.4 mEq/kg, and a free fatty acid content of 1.37%. Biochemical tests on the bacterial isolates from dental caries samples identified several species, including Actinomyces spp., Streptococcus spp., Lactococcus spp., Lacticaseibacillus paracasei, Staphylococcus aureus strain CIB, Bifidobacterium spp., Veillonella spp., and Bacillus subtilis. Antimicrobial activity assay shows that clove oil exhibited significant inhibition of microbial growth at higher concentrations: B.subtilis had inhibition zones of 12 mm at 100 mg/ml, 6 mm at 50 mg/ml, and 2 mm at 25 mg/ml. Similarly, Lacticaseibacillus agile 1365 showed inhibition zones of 14 mm at 100 mg/ml, 8 mm at 50 mg/ml, and 3 mm at 25 mg/ml. S.aureus strain B3A22 had inhibition zones of 10 mm at 100 mg/ml and 6 mm at 50 mg/ml. In contrast, L. paracasei showed minimal inhibition, indicating lower susceptibility to clove oil. On the other hand, the result also illustrates that clove extract was more effective at lower concentrations compared to clove oil. B.subtilis had inhibition zones of 14 mm at 100 mg/ml, 8 mm at 50 mg/ml, and 5 mm at 25 mg/ml. L.paracasei demonstrated inhibition zones of 16 mm at 100 mg/ml, 11 mm at 50 mg/ml, and 8 mm at 25 mg/ml. S.aureus strain B3A22 had inhibition zones of 10 mm at 100 mg/ml and 6 mm at 50 mg/ml. The Minimum Inhibitory Concentration (MIC) of clove oil was found to be 25 mg/ml for B.subtilis, 100 mg/ml for L.paracasei, 25 mg/ml for L.agile 1365, and 25 mg/ml for both S.aureus strain CIB and strain B3A22 respectively. In comparison, clove extract demonstrated lower MIC values: 12.5 mg/ml for B.subtilis, 12.5 mg/ml for L.paracasei, 12.5 mg/ml for L.agile 1365, 25 mg/ml for S.aureus strain CIB, and 25 mg/ml for S.aureus strain B3A22. The Minimum Bactericidal Concentration (MBC) of clove oil was 50 mg/ml for B.subtilis, for L.paracasei, 25 mg/ml for L.agile 1365, 50 mg/ml for S.aureus strain CIB, and 100 mg/ml for S.aureus strain B3A22. In contrast, clove extract showed an MBC of 25 mg/ml for B.subtilis, 50 mg/ml for L.paracasei, 25 mg/ml for L.agile 1365, 50 mg/ml for S.aureus strain CIB, and 25 mg/ml for S.aureus strain B3A22. These results underscore the significant antibacterial activity of clove extract, particularly due to its higher potency at lower concentrations compared to clove oil, supporting its potential use in developing alternative treatments for dental caries.

Response surface optimization for supercritical carbon dioxide extraction of Korarima (Aframomum corrorima) seed oil and its antibacterial activity evaluation

Oils extracted from natural plants are valuable resources because of their diverse biocidal activity against microorganisms. This paper reports, for the first time, supercritical CO2 extraction of oil from Korarima (Aframomum corrorima) seeds and its antibacterial activity evaluation. The influences of pressure, temperature, and extraction time on the yield of supercritical CO2-extracted oil (scCO2-extracted oil) were optimized using the Response Surface Methodology. Under the optimal extraction conditions of 46 °C, 15.5 MPa, and 147 min, the extraction yield reached 1.60±0.04 %, consistent with the theoretical value of 1.58 %. The compositions of the scCO2-extracted oil were identified by GC-MS, primarily consisting of nerolidol (33.97–41.20 %), geraniol (23.08–24.50 %), and α-terpinene (8.90–9.06 %). The oil exhibited significant antibacterial activity against Staphylococcus. aureus with a minimum inhibitory concentration of 1 mg·mL−1. This study highlights the potential applications of supercritical CO2 extraction technology for extracting Korarima seed oil and its use as an antibacterial ingredient in cosmetics and pharmaceuticals.

Zirconium-doped zinc nanocomposites (ZDZN): Preparation, characterization, and evaluation of antibacterial activity

The present study focuses on zirconium-doped zinc nanocomposites (ZDZN), representing a novel class of materials with antibacterial and antifungal properties. This work involves the preparation, characterization, and evaluation of the antibacterial activity of ZDZN. Zinc oxide nanoparticles were doped with varying concentrations of zirconium ions to create nanocomposites using a simple precipitation technique. The structural, morphological, and chemical properties were investigated using EDS, TEM, SEM, and XRD analyses. The results indicated the successful incorporation of zirconium ions into the lattice of zinc oxide nanoparticles, resulting in nanocomposites with well-defined shapes and compositions. Agar diffusion studies were conducted to assess the antibacterial activities of the nanocomposites against various bacterial and fungal species. The findings revealed that ZDZN exhibited superior antibacterial activity compared to pure zinc oxide nanoparticles, attributed to the concentration-dependent effect of the zirconium dopant. Furthermore, the nanocomposites demonstrated excellent biocompatibility and stability, making them highly suitable for applications in biomedical devices and antimicrobial coatings.

Preparation of trimethoprim/methyl β-cyclodextrin complexes, in vitro and in vivo pharmacokinetic study, and evaluation of antibacterial activity in combination with the complex of sulfamethoxazole/methyl β-cyclodextrin

Through cyclodextrin selection from phase solubility study, complexation method screening, and complexation condition optimization by using single and orthogonal strategy, the complexes of trimethoprim with methyl β-cyclodextrin, HP β-cyclodextrin and HP-γ-cyclodextrin with the best solubility increasing so far were prepared and confirmed by FTIR, DSC and proton NMR spectra. The in vitro pharmacokinetic study showed that trimethoprim was 80 %–90 % released in three complexes in 20 min., and in their dog's in vivo pharmacokinetic study, the Cmax was increased from 0.22 µg/mL to 0.85 µg/mL, 0.7 µg/mL and 0.72 µg/mL, the AUC0∼40 was increased from 2.35 µg*h/mL to 3.94 µg*h/mL, 5.06 µg*h/mL and 6.73 µg*h/mL, the LC was shorten from 2.17 L/kg/h to 0.89 L/kg/h, 0.56 L/kg/h and 1.07 L/kg/h for the complexes with methyl β-cyclodextrin, HP β-cyclodextrin and HP-γ-cyclodextrin respectively. After combination with sulfamethoxazole cyclodextrin complex, the antibacterial activity of the complex of trimethoprim with methyl β-cyclodextrin was increased significantly compared with the pure drug alone, indicated that this complex can be used as new potent antibacterial agent.

Silver Nanoparticles Loaded with Bark Extract of Sterculia foetida: Their Green Synthesis, Characterization, and Anti-bacterial Activity Evaluation

Sterculia foetida is a subject of interest in many scientific fields as researchers look for novel treatments because of its varied medicinal qualities and chemical richness. Terpenoids are aromatic and aliphatic chemicals with anti-bacterial properties and can prevent free radical damage. They are present in S. foetida extract. Moreover, it possesses immunomodulatory, hepatoprotective, antiviral, antioxidant, anti-inflammatory, and antifungal properties. This work aims to green synthesize, characterize, and evaluate the anti-bacterial activity of Sterculia foetida bark extract-loaded silver nanoparticles. Chemicals like Methanol, Petroleum Ether, and water have been used to extract the phytoconstituents from the plant bark. AgNO3 and Silver have been used to synthesize the nanoparticles. Instruments like ATR-IR Spectrophotometer, UV- spectrophotometer, DLS, and SEM instruments have been used to characterize the nanoparticles. Bacterial strains like Staphylococcus aureus (ATCC-6538), Escherichia coli (ATCC 25922), saline water, AMX30, swab stick, inoculation loop, susceptibility scale have been used for studying the anti-bacterial activity. DLS and zeta potential analysis demonstrated the creation of stable nanoparticles with a particle size of 79 nm. The anti-bacterial activity of AgNPs with the methanolic bark extract showed significant anti-bacterial activity compared to the standard marketed drug AMX30. The highest zone of inhibition was observed against gram-positive bacteria S.aureus (1.68 cm) and gram-negative bacteria E.coli (1.74 cm), respectively, at 500 μg/ml concentration. The study concludes that greenly synthesized S. foetida bark extract containing nanoparticles is a potential anti-bacterial agent, especially against gram-negative bacteria. Further, in vivo studies are needed to establish its potential. Keywords: Sterculia foetida, Green synthesis, Silver Nanoparticles (AgNPs), ATR-IR, DLS, SEM, Zeta-potential, Anti-bacterial.

Evaluation of antibacterial activity on nanoline-array surfaces with different spacing

Extensive research has been conducted on anti-biofouling or antibacterial surfaces, with nanostructured surfaces that mimic cicada and dragonfly wings emerging as promising candidates for mechano-bactericidal applications. These biomimetic nanostructured surfaces are capable of exerting a bactericidal effect by directly damaging the membranes of bacteria attached to nanostructures. Although research on bactericidal effect using various nanostructures have been conducted, no specific studies have yet reported on the antibacterial efficiency of the surface having nanoline array, especially regarding the spacing between nanolines. This study details the fabrication of nanoline array via ultraviolet (UV) molding with polyurethane acrylate (PUA), noted for its UV sensitivity and rapid curing, enabling the fabrication of precise and scalable nanoscale structures. Investigation into the nanoline array’s antibacterial effects against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) reveals that nanoline spacing critically influences bacterial adherence and viability, with specific spacings enhancing antibacterial properties. Scanning electron microscopy (SEM) and confocal microscopy analyses show that surface topography significantly affects bacterial behavior, with specific spacings leading to varied bacterial responses, including membrane damage and altered attachment patterns. The study highlights the potential of nanoline array in fabricating surfaces with tailored antibacterial properties, emphasizing the importance of nanoscale design in influencing bacterial interaction and viability. We also confirm the relative mechanical rigidity of the nanoline array, which exhibits antibacterial effects, through both experimental observations and numerical analysis. This indicates our proposed nanoline-array surface could have potential future applications in mechanical anti-bacterial functions that require such structural robustness.