P-Doped Carbon Quantum Dots with Antibacterial Activity

It is a major challenge to effectively inhibit microbial pathogens in the treatment of infectious diseases. Research on the application of nanomaterials as antibacterial agents has evidenced their great potential for the remedy of infectious disease. Among these nanomaterials, carbon quantum dots (CQDs) have attracted much attention owing to their unique optical properties and high biosafety. In this work, P-doped CQDs were prepared by simple hydrothermal treatment of m-aminophenol and phosphoric acid with fluorescence emission at 501 nm when excited at 429 nm. The P-doped CQDs showed effective antibacterial activity against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). The minimal inhibitory concentrations (MICs) of P-doped CQD were 1.23 mg/mL for E. coli and 1.44 mg/mL for S. aureus. Furthermore, the morphologies of E. coli cells were damaged and S. aureus became irregular when treated with the P-doped CQDs. The results of zeta potential analysis demonstrated that the P-doped CQDs inhibit antibacterial activity and destroy the structure of bacteria by electronic interaction. In combination, the results of this study indicate that the as-prepared P-doped CQDs can be a promising candidate for the treatment of bacterial infections.

Lactoferrin, Quercetin, and Hydroxyapatite Act Synergistically against Pseudomonas fluorescens

Pseudomonas fluorescens is an opportunistic, psychotropic pathogen that can live in different environments, such as plant, soil, or water surfaces, and it is associated with food spoilage. Bioactive compounds can be used as antimicrobials and can be added into packaging systems. Quercetin and lactoferrin are the best candidates for the development of a complex of the two molecules absorbed on bio combability structure as hydroxyapatite. The minimum inhibiting concentration (MIC) of single components and of the complex dropped down the single MIC value against Pseudomonas fluorescens. Characterization analysis of the complex was performed by means SEM and zeta-potential analysis. Then, the synergistic activity (Csyn) of single components and the complex was calculated. Finally, the synergistic activity was confirmed, testing in vitro its anti-inflammatory activity on U937 macrophage-like human cell line. In conclusion, the peculiarity of our study consists of optimizing the specific propriety of each component: the affinity of lactoferrin for LPS; that of quercetin for the bacterial membrane. These proprieties make the complex a good candidate in food industry as antimicrobial compounds, and as functional food.

Synthesis of Copper Nanoparticles Stabilized with Organic Ligands and Their Antimicrobial Properties

In this work, we report the synthesis of copper nanoparticles (Cu NPs), employing the chemical reduction method in an aqueous medium. We used copper sulfate pentahydrate (CuSO4·5H2O) as a metallic precursor; polyethylenimine (PEI), allylamine (AAM), and 4-aminobutyric acid (AABT) as stabilizing agents; and hydrated hydrazine as a reducing agent. The characterization of the obtained nanoparticles consisted of X-ray, TEM, FTIR, and TGA analyses. Through these techniques, it was possible to detect the presence of the used stabilizing agents on the surface of the NPs. Finally, a zeta potential analysis was performed to differentiate the stability of the nanoparticles with a different type of stabilizing agent, from which it was determined that the most stable nanoparticles were the Cu NPs synthesized in the presence of the PEI/AAM mixture. The antimicrobial activity of Cu/PEI/AABT toward P. aeruginosa and S. aureus bacteria was high, inhibiting both bacteria with low contact times and copper concentrations of 50–200 ppm. The synthesis method allowed us to obtain Cu NPs free of oxides, stable to oxidation, and with high yields. The newly functionalized Cu NPs are potential candidates for antimicrobial applications.

Biosynthesis of Silver Nanoparticles Using Juglans Regia Green Husk (Walnut) Water Extract and evaluation Antibacterial activity

Biosynthesis of Ag-NPs at room temperature by using Juglans regia (J. regia) green husk extract which acts as reductant and stabilizer, simultaneously. The Ag/J. regia were characterized by using UV–visible, zeta potential, TEM, and AFM. Formation of Ag/ J. regia was determined by UV–vis spectroscopy, where absorption maxima surface plasmon at 400-460 nm. The zeta potential analysis indicated that J. regia green husk extract was negative and increasing in Ag/ J. regia. TEM images show the mean particle size was 31.37 nm with the standard deviation of 7.1 nm, where confirm by AFM measurements. The XRD study indicates the crystalline nature of the Ag-NPs. The antibacterial activity of Ag-NPs was investigated against Gram-positive and Gram-negative bacteria by the disc diffusion method were found to have high antibacterial activity. These results show that Ag-NPs can be useful in different biologic research and biomedical applications.

Synthesis, Characterization And Assessment of Anti Microbial Behaviour of Goat Faecal Mediated Silver Nanoparticles- Fed on Tirumala Hills

To synthesize, characterize, and to assess the anti-microbial activity of silver nanoparticles (AgNPs) induced by goat fecal matter. The AgNPs were processed by the microwave heating method and the characterization was accomplished by employing various spectroscopic approaches such as UV-Visible, FTIR spectroscopy, XRD, Particle size, and Zeta potential analysis. The lmax for both extracts were found at 426& 438nm. The wideband corresponded to O-H stretching vibrations at 3384.0 cm-1, 3273.9 cm-1 and 3366.2 cm-1, bands at 2918.5 cm-1, 2922.5 cm-1, 2853.2 cm-1, and 2850.2 cm-1 corresponded to the N–H and C–H stretching. The bands at 1638.1 cm-1, 1651.9, and 1686.5 cm-1 corresponded to the C=C stretch. Bands of 1460.3 cm-1, 1450.4 cm-1, 1409.2 cm-1 and 1376.3 cm-1 corresponded to C-N, C-C bond stretching vibrations. The stretch of C-O indicates bands at 1159.7 cm-1, 1033.2 cm-1, and 1032.8 cm-1. The synthesized AgNPsdemonstrated good anti-microbial activity on gram +Ve (S.aureus) and gram -Ve (E.coli) bacteria. Bio/Green synthesized AgNPs have shown improved biological performance, this tends to minimize production cost, pollution-free, less chemical usage, and stable generation of nanoparticles.

Green synthesis of silica nanoparticles from olive residue and investigation of their anticancer potential

Aim: To synthesize silica nanoparticles (SNPs) from olive residue with anticancer properties. Methods: SNPs were synthesized from olive residue ash (ORA). After characterization, cytotoxicity of the SNPs was assessed in vitro, with measurement of reactive oxygen species (ROS) levels. Results: The average diameter of the synthesized SNPs was 30–40 nm, and zeta potential analysis suggested they were stable. The synthesized SNPs were less cytotoxic than commercially available SNPs against fibroblast cells, and the cytotoxic effect on breast cancer cells was significantly higher compared with fibroblast cells. SNPs showed greater uptake into cancer cells where there was greater production of free radicals. Conclusion: SNPs synthesized from ORA have potential anticancer applications because they are more cytotoxic toward cancer cells than fibroblast cells.

Effects of Tryptophan on the Polymorphic Transformation of Calcium Carbonate: Central Composite Design, Characterization, Kinetics, and Thermodynamics

The objectives of this study were to: (i) determine the effects of tryptophan on the polymorphic phase transformation of CaCO3, (ii) investigate the thermal degradation characteristics of CaCO3 in terms of kinetics and thermodynamics using the Coats–Redfern method, and (iii) assess the influence of the experimental conditions on the vaterite composition of CaCO3 using response surface methodology based on central composite design. First, the CaCO3 crystals were prepared and analyzed using XRD, FTIR, SEM, BET, AFM, and zeta potential analysis. Based on the characterization results, the shape of the CaCO3 crystals changed from smooth cubic calcite crystals to porous irregular spherical-like vaterite crystals with increasing tryptophan concentration. Meanwhile, the kinetic results showed that the thermal degradation of CaCO3 followed the shrinkage geometrical spherical mechanism, R3 and the average activation energy was 224.6 kJ/mol. According to the results of the experimental design, the tryptophan concentration was the most influential variable affecting the relative fraction of vaterite in the produced crystals. It can be concluded that tryptophan is important for better understanding and controlling the polymorph, size, and morphology of CaCO3 crystals.

Functionalization of Gold Nanostars with Cationic β-Cyclodextrin-Based Polymer for Drug Co-Loading and SERS Monitoring

Gold nanostars (AuNSs) exhibit modulated plasmon resonance and have a high SERS enhancement factor. However, their low colloidal stability limits their biomedical application as a nanomaterial. Cationic β-cyclodextrin-based polymer (CCD/P) has low cytotoxicity, can load and transport drugs more efficiently than the corresponding monomeric form, and has an appropriate cationic group to stabilize gold nanoparticles. In this work, we functionalized AuNSs with CCD/P to load phenylethylamine (PhEA) and piperine (PIP) and evaluated SERS-based applications of the products. PhEA and PIP were included in the polymer and used to functionalize AuNSs, forming a new AuNS-CCD/P-PhEA-PIP nanosystem. The system was characterized by UV–VIS, IR, and NMR spectroscopy, TGA, SPR, DLS, zeta potential analysis, FE-SEM, and TEM. Additionally, Raman optical activity, SERS analysis and complementary theoretical studies were used for characterization. Minor adjustments increased the colloidal stability of AuNSs. The loading capacity of the CCD/P with PhEA-PIP was 95 ± 7%. The physicochemical parameters of the AuNS-CCD/P-PhEA-PIP system, such as size and Z potential, are suitable for potential biomedical applications Raman and SERS studies were used to monitor PhEA and PIP loading and their preferential orientation upon interaction with the surface of AuNSs. This unique nanomaterial could be used for simultaneous drug loading and SERS-based detection.

Biosynthesis of Silver Nanoparticles and Their Biocontrol Potentials Against Aspergillus Niger and Fusarium Udum

Silver nanoparticles can be biosynthesized from bacteria, fungi, and plant extracts but due to their ability to synthesize nanoparticles in varying sizes and shapes at ease, bacterial has drawn interest. Bacterial based biosynthesis is effective, inexpensive, and simple thus, Pseudomonas fluorescence cell filtrates were used to synthesize silver nanoparticles in the present study. The chromatic shifts (yellow to brown) in the media after overnight incubation and the absorption of UV-Vis spectra at 420 nm confirmed the biosynthesis of AgNP’s. Besides that, the SPR analysis of AgNP’s showed a 400–500 nm band width, supporting the formation of silver nanoparticles and their small size with a uniform shape. AgNP’s transmission electron microscopy (TEM) images confirmed their shape as quasi spherical, mean size as 30 nm and anisotropy. From the Zeta potential analysis (-42.7 mV at pH = 7 with a single peak), highly repulsive nature of nanoparticles was confirmed. On the other hand, bio-fabricated silver nanoparticles were tested for antifungal activity against Fusarium udum and Aspergillus niger under in vitro conditions. At 150 ppm concentration of AgNP’s, Fusarium udum and Aspergillus niger were inhibited up to 100 and 80.50 %, respectively. In conclusion, synthesis of nanoparticle with aqueous Pseudomonas fluorescence extract is simple and environmentally benign.