Antibacterial Efficacy of Zinc oxide nanoparticles against Serratia marcescens (ATCC 43862) and Enterococcus faecalis (ATCC 29121)

Zinc oxide nanoparticles (ZnO NPs) are a novel and alternative biomaterial for active biomedical applications among all metal and metallic oxide nanoparticles due to less toxicity and biocompatibility with human cells. In this study, we studied the growth curve of Serratia marcescens and Enterococcus faecalis to identify the mid-log phase of the bacterial growth to perform the exposure with ZnO NPs for investigating the antibacterial efficacy. The INT assay was used to determine the anti-bactericidal efficiency of ZnO NPs against S. marcescens and E. faecalis. The results showed that both the test bacteria attained the mid-log phase at the 5th hour. The determination of minimum inhibitory concentration (MIC) demonstrated a higher efficacy of ZnO NPs on the Gram-positive bacterium E. faecalis compared to the Gram-negative bacterium S. marcescens. The present study reports a higher susceptibility of Gram-positive bacterium over Gram-negative bacterium to the treatment of ZnO NPs

Structure and Reactivity of Halogenated GC PNA Base Pairs – A DFT Approach

The present study explored the structural and reactivity relationship of halogenated G-C PNA base pairs using density functional theory (DFT) calculations. The halogens such as F, Cl, and Br are substituted by replacing H atoms involved in H-bonds of the base pairs. All structures were optimized using the B3LYP/6-311++G** theory level, and positive frequencies confirmed their equilibrium states. To understand the structural variations of the considered halogenated systems, the bond distances of R─X, R─H, and X/H•••Y and the bond angles of R─X•••Y were analyzed. The obtained structural parameters and interaction energies are comparable with the previous theoretical reports. In addition, the interaction energies (Eint) and quantum molecular descriptors (QMD) are also calculated to understand the difference between halogenated PNA systems and their non-halogenated counterparts. In this study, the enhancement in the reactivity properties  of halogenated PNA systems has been demonstrated, which indicates their improved responsive characteristics in various chemical reactions. Based on the available results, the halogenated PNA systems, carefully considering their substitutional position, facilitate better accommodation for the triplex formation of dsDNA/dsRNA. Therefore, it is concluded that the improved reactivity properties of halogenated PNA base pairs would make them potential candidates for various biological applications

Synthesis and Characterization of Magnesium Doped Ferric Sulphate Nanoparticles (Mg-Fe2SO3 NPs) for Agriculture Applications

The present study aimed to synthesize the magnesium doped ferric sulphate nanoparticles (Mg-Fe2SO3 NPs) and investigate their seed germination efficacy. Mg-Fe2SO3 NPs were prepared by a simple and cost-effective method and subjected to characterization. The X-ray Diffraction (XRD) spectrum revealed the crystalline nature of Mg-Fe2SO3 NPs with an average crystallite size of 36.41 nm. The field emission scanning electron microscope (FESEM) image displayed the agglomeration of Mg-Fe2SO3 NPs with the shape of the grains appeared like starfish which has limbs grown from a common cluster. The energy dispersive X-ray spectroscopy (EDS) demonstrated the existence of C (10.5%), O (49.14%), Fe (26.67%), Mg (0.78%) and S (13.35%) elements in Mg-Fe2SO3 NPs. It also revealed the absence of impurities in the synthesized NPs. Through Fourier transform infrared spectroscopy (FTIR), Mg-Fe2SO3 NPs showed the characteristic peaks at 615.29cm-1, 1130.29cm-1, 1400.32 cm-1and 1633.71cm-1 which corresponded to Fe-O, C-N, O-H and N-H vibration respectively. Further, the seed germination study revealed that the Mg-Fe2SO3 NPs treatment caused a significant increase in seedling growth of cowpea (Vigna unguiculata) seeds compared to the untreated samples

Impact of Metallic Nanoparticles on the Nutritional Values of Spirulina

Spirulina has high nutritional values and anti-oxidative properties. It is a staple diet due to its easy cultivation and greater nutritional values in biological macromolecules (proteins, lipids, and carbohydrates), pigments (chlorophyll, carotenoids, phycobiliproteins) vitamins, minerals, phenolic compounds, and amino acids. Spirulina also has been used as a nutraceutical to treat numerous diseases and disorders due to its promising therapeutic values. However, extensive anthropogenic activities cause the discharge of metals and metallic nanoparticles into the environment that might cause toxicity to marine and freshwater microalgae due to bioaccumulation. The presence of metals in the environment beyond the normal range does not only affect the growth but also the nutritional values of microalgae. The nutritional properties and usage of Spirulina along with the harmful effects of metals and metallic nanoparticles on Spirulina are highlighted and summarized in this paper

Antibacterial Effect of Green Synthesized Silver Nanoparticles using Cineraria maritima

Nanoparticles display entirely novel physicochemical characteristics for specific applications because of their exceptional size and shape. Owing to the present study, we reported biosynthesis, characterization and antibacterial properties of Cineraria maritima (Cm) assisted silver nanoparticles (Ag NPs). The surface plasmon vibration, crystalline structure, surface morphology, elemental composition, and possible functional molecules vibration of prepared Cm-Ag NPs were characterized by different instrumentation techniques. The spectrum of UV-Vis of Cm-Ag NPs showed maximum plasma intensity occurred around 425nm. XRD spectrum showed the face-centred cubic (FCC) nature of Cm-Ag NPs. The SEM image of the Cm-Ag NPs demonstrated a predominantly spherical shape with cluster formation of small particles to large particles with sizes ranging from 21.57 nm to 39.16 nm. EDS spectrum indicated the existence of Ag elements in Cm-Ag NPs. FTIR intense peaks of Cm-Ag NPs showed the different functional molecules such as phenol, alkene, aldehydes, and a carbonyl group. In addition, Cm-Ag NPs coated textile cotton fabric sample showed substantial anti-bacterial properties against a tested bacterial pathogen

Biogenic Preparation, Characterization, and Biomedical Applications of Chitosan Functionalized Iron Oxide Nanocomposite

Chitosan (CS) functionalization over nanomaterials has gained more attention in the biomedical field due to their biocompatibility, biodegradability, and enhanced properties. In the present study, CS functionalized iron (II) oxide nanocomposite (CS/FeO NC) was prepared using Sida acuta leaf extract by a facile and eco-friendly green chemistry route. Phyto-compounds of S. acuta leaf were used as a reductant to prepare CS/FeO NC. The existence of CS and FeO crystalline peaks in CS/FeO NC was confirmed by XRD. FE-SEM analysis revealed that the prepared CS/FeO NC were spherical with a 10–100 nm average size. FTIR analyzed the existence of CS and metal-oxygen bands in the prepared NC. The CS/FeO NC showed the potential bactericidal activity against E. coli, B. subtilis, and S. aureus pathogens. Further, CS/FeO NC also exhibited the dose-dependent anti-proliferative property against human lung cancer cells (A549). Thus, the obtained outcomes revealed that the prepared CS/FeO NC could be a promising candidate in the biomedical sector to inhibit the growth of bacterial pathogens and lung cancer cells

Study of Chlorella vulgaris from Different Growth Phases as Biosensor for Detection of Titanium and Silver Nanoparticles in Water

The increased use of metallic nanoparticles has led to concern for environmental contamination and disruption in water quality. Therefore, effective screening of metallic nanoparticles is important for detecting metallic nanoparticles in aquatic environments. Biosensors offer several advantages, including high sensitivity to pollutants, short response time, energy efficiency, and low waste generation. In this study, a whole-cell biosensor was developed using microalga Chlorella vulgaris as a recognition element, and its fluorescence response was used as a measuring parameter for detecting the presence of titanium dioxide (TiO2) and silver (Ag) nanoparticles in water. The responses of C. vulgaris at the lag, exponential, and stationary phases to different concentrations of TiO2 and Ag nanoparticles were studied. The results showed that in TiO2 and Ag nanoparticles exposures, the highest fluorescence change (50-150%) was observed at the lag phase, whereas the lowest fluorescence change (40-75%) was observed at the stationary phase. A significant fluorescence change was observed in 15 min. The immobilized C. vulgaris under TiO2 and Ag nanoparticles exposures showed 30-180% higher fluorescence change than the negative control, indicating the potential of C. vulgaris as a biosensor for rapid detection of TiO2 and Ag nanoparticles in water. The mathematical modeling of the responses of C. vulgaris to TiO2 and Ag nanoparticles at 15 min of exposure with high R2 indicated that this biosensor is sensitive to the concentration tested (0.010–10.000 mg.L-1). Taken together, these results reveal that, for the first time, it is possible to detect TiO2 and Ag nanoparticles in water within a very short time using a microalgae-based biosensor. Moreover, no genetic engineering requirement makes this biosensor simple, economical, and free from the restriction on genetically modified microorganisms for environmental applications

Facile Synthesis and Characterization of Chitosan Functionalized Silver Nanoparticles for Antibacterial and Anti-Lung Cancer Applications

In the treatment of bacterial contamination, the problem of multi-drug resistance is becoming an increasingly pressing concern. Nanotechnology advancements enable the preparation of metal nanoparticles that can be assembled into complex systems to control bacterial and tumor cell growth. The current work investigates the green production of chitosan functionalized silver nanoparticles (CS/Ag NPs) using Sida acuta and their inhibition efficacy against bacterial pathogens and lung cancer cells (A549). Initially, a brown color formation confirmed the synthesis, and the chemical nature of the synthesized NPs were examined by UV-vis spectroscopy, Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) coupled with energy dispersive spectroscopy (EDS), and transmission electron microscopy (TEM). FTIR demonstrated the occurrence of CS and S. acuta functional groups in the synthesized CS/Ag NPs. The electron microscopy study exhibited CS/Ag NPs with a spherical morphology and size ranges of 6–45 nm, while XRD analysis demonstrated the crystallinity of Ag NPs. Further, the bacterial inhibition property of CS/Ag NPs was examined against K. pneumoniae and S. aureus, which showed clear inhibition zones at different concentrations. In addition, the antibacterial properties were further confirmed by a fluorescent AO/EtBr staining technique. Furthermore, prepared CS/Ag NPs exhibited a potential anti-cancer character against a human lung cancer cell line (A549). In conclusion, our findings revealed that the produced CS/Ag NPs could be used as an excellent inhibitory material in industrial and clinical sectors

Thickness dependence on structural, dielectric and AC conduction studies of vacuum evaporated Sr doped BaTiO3 thin films

Barium titanate (BaTiO3) doped with Strontium (BST) nanoparticles prepared by using wet chemical method were thermally evaporated on to well cleaned glass substrates under the vacuum of 2 × 10−5 Torr, using 12A4 Hind Hivac coating unit. The thickness of the film was measured by quartz crystal monitor. From X-ray analysis, it has been found that BaTiO3 nanoparticles possess tetragonal structure and deposited films has a polycrystalline in nature, whereas the crystallinity of film increases with increase of temperature. Surface morphology of the prepared thin film was found to be uniform. The transport mechanism in these films under a.c. fields was studied in the frequency range 12 Hz to 100 kHz, at different temperatures (303–483 K). The dependence of dielectric constant and loss factor for different thickness was investigated and results are discussed. The process of a.c. conduction has been explained on the basis of hopping conduction mechanism. The dielectric constant (ɛ′), temperature co-efficient of capacitance (TCC) and temperature co-efficient of permitivity (TCP) were estimated. The dependence of activation energy on thickness also studied and reported

Synthesis and Characterization of Novel Fe 3 O 4 /PVA/Eggshell Hybrid Nanocomposite for Photodegradation and Antibacterial Activity

In the 21st century, hybrid nanocomposites were widely used in bioelectronic, biosensing, photocatalytic, and biomedical applications. In the present study, we fabricated a novel Fe3O4/PVA/Eggshell hybrid nanocomposite and physicochemically characterized it using powder XRD, EDS, FTIR, VSM, and HR-TEM analysis. The XRD spectrum revealed the crystalline and FCC configuration of Fe3O4 NPs with average crystal size of 16.28 nm, and the HRTEM image indicates the prepared hybrid nanocomposite is of spherical shape with less agglomeration. This hybrid nanocomposite showed a significant photodegradation property in degrading organic pollutants such as congo red and crystal violet dyes under the sunlight irradiation. In addition, the hybrid nanocomposite also displayed a potent antibacterial property against different Gram +ve and Gram −ve bacterial pathogens. This study provides a significant example in the overview of fabrication of cost effectively, eco-friendly, and multiple-application hybrid nanocomposites through eggshell membrane fibers