The antibacterial and antihemolytic activities assessment of zinc oxide nanoparticles synthesized using plant extracts and gamma irradiation against the uro-pathogenic multidrug resistant Proteus vulgaris.

In the case of Proteus vulgaris infection, the increased occurrence of multidrug-resistance strains has become a critical challenge in the treatment of urinary tract diseases. Therefore, using plant extracts as eco-friendly antibacterial provides an attractive solution to battle bacterial infection. The current study investigates the antibacterial and antihemolytic activity of nine medicinal plant extracts against P. vulgaris. Citrus limon extract at 150 µg/ml exhibited the highest antimicrobial action against P. vulgaris (the inhibition zone diameter; 22.7 mm). Zinc oxide nanoparticles (ZnO NPs) are synthesized using the plant extracts of C. limon, Allium sativum, Sonchus bulbosus, Allium cepa, and Asparagus racemosus. The antibacterial activity of ZnO NPs synthesized using C. limon extract at 150 µg/ml is significantly increased (33.8 mm). ZnO NPs synthesized using A. cepa, A. racemosus, and C. limon plant extracts are effectively protective for human red blood cells. The ZnO NPs synthesized using C. limon extract are characterized using UV-Visible spectroscopy, FTIR, XRD, and TEM. FTIR revealed that the plant extracts may serve as reducing and capping agents of ZnO NPs. XRD spectra confirmed the crystallinity of ZnO NPs. TEM image demonstrated the formation of spherical shapes of ZnO NPs with an average size of 37.05 nm. SEM of P. vulgaris cells treated with ZnO NPs showed cellular morphological damage compared to the untreated cells. ZnO NPs are synthesized by gamma irradiation as a clean and novel method. This study recommended the promising uses of the biosynthesized ZnO NPs using plant extracts as a natural, unique approach, to control the pathogenicity of P. vulgaris.

Crotalaria verrucosa Leaf Extract Mediated Synthesis of Zinc Oxide Nanoparticles: Assessment of Antimicrobial and Anticancer Activity.

In this work, we present an ecofriendly, non-hazardous, green synthesis of zinc oxide nanoparticles (ZnO NPs) by leaf extract of Crotalaria verrucosa (C. verrucosa). Total phenolic content, total flavonoid and total protein contents of C. verrucosa were determined. Further, synthesized ZnO NPs was characterized by UV-visible spectroscopy (UV-vis), X-ray diffractometer (XRD), Fourier transform infra-red (FTIR) Spectra, transmission electron microscope (TEM), and Dynamic light scattering (DLS) analysis. UV-vis shows peak at 375 nm which is unique to ZnO NPs. XRD analysis demonstrates the hexagonal phase structures of ZnO NPs. FTIR spectra demonstrates the molecules and bondings associated with the synthesized ZnO NPs and assures the role of phytochemical compounds of C. verrucosa in reduction and capping of ZnO NPs. TEM image exhibits that the prepared ZnO NPs is hexagonal shaped and in size ranged between 16 to 38 nm which is confirmed by DLS. Thermo-gravimetric analysis (TGA) was performed to determine the thermal stability of biosynthesized nanoparticles during calcination. The prepared ZnO NPs showed significant antibacterial potentiality against Gram-positive (S. aureus) and Gram-negative (Proteus vulgaris, Klebsiella pneumoniae, and Escherichia coli) pathogenic bacteria and SEM image shows the generalized mechanism of action in bacterial cell after NPs internalization. In addition, NPs are also found to be effective against the studied cancer cell lines for which cytotoxicity was assessed using MTT assay and results demonstrate highest growth of inhibition at the concentration of 100 µg/mL with IC50 value at 7.07 µg/mL for HeLa and 6.30 µg/mL for DU145 cell lines, in contrast to positive control (C. verrucosa leaf extract) with IC50 of 22.30 µg/mL on HeLa cells and 15.72 µg/mL on DU145 cells. Also, DAPI staining was performed in order to determine the effect on nuclear material due to ZnO NPs treatment in the studied cell lines taking leaf extract as positive control and untreated negative control for comparison. Cell migration assay was evaluated to determine the direct influence of NPs on metastasis that is potential suppression capacity of NPs to tumor cell migration. Outcome of the synthesized ZnO NPs using C. verrucosa shows antimicrobial activity against studied microbes, also cytotoxicity, apoptotic mediated DNA damage and antiproliferative potentiality in the studied carcinoma cells and hence, can be further used in biomedical, pharmaceutical and food processing industries as an effective antimicrobial and anti-cancerous agent.

Development of cost effective metal oxide semiconductor based gas sensor over flexible chitosan/PVP blended polymeric substrate.

In the present work, biodegradable and flexible chitosan/polyvinylpyrrolidone (CHP) polymeric substrate was fabricated by solvent casting method. This is a novel demonstration of the combination of natural polymer (chitosan) and synthetic polymer (PVP) for next-generation semiconductor device applications. The ZnO thin films were successfully synthesized on these polymeric substrates by facile drop-casting method for gas sensing applications. The hydrogen gas sensing properties of ZnO deposited on the polymeric substrate and SiO2 substrate show similar performance. The structural, morphological, optical, thermal, and tensile strength of the CHP substrate were studied using X-ray diffraction (XRD), Scanning electron microscopy (SEM), UV-visible spectroscopy, Derivative thermogravimetric analysis (DTG), and Universal testing machine (UTM), respectively. Our study suggests that the biodegradable CH/PVP flexible polymeric substrate provides a new way for the implementation of an eco-friendly green substrate in numerous electronic device applications.

Synthesis of ZnO nanoparticles supported on mesoporous SBA-15 with coordination effect -assist for anti-bacterial assessment.

Polyethyleneimine (PEI) was immobilized on SBA-15 for obtaining polyethyleneimine-modified silica PEI@SBA-15s (PEI@SBA-1.0, PEI@SBA-1.5, and PEI@SBA-2.0). With the coordination from PEI, zinc ions were impregnated on the PEI@SBA-15s, and then, Zn2+-PEI@SBA-15s were calcined at 550 ℃ to obtain the nano zinc oxide loaded on the mesoporous silica, ZnO-SBA-15s (ZnO-SBA-1.0, ZnO-SBA-1.5, and ZnO-SBA-2.0). The anti-bacterial activity of ZnO-loaded SBA-15 was; thereafter, assessed by the zone of inhibition and enzyme labeling methods. The results confirmed that the coordination ability of the imino groups in PEI helped adsorb more zinc ions during the process of impregnation so that more nano-ZnO could be supported on the surface of SBA-15. The modification did not change the mesostructure of the two-dimensional hexagonal phase and orderliness of SBA-15. At the mass ratio of PEI:SBA-15 = 1.0:1, 1.5:1, and 2.0:1, the concentration of zinc element (wt.%) was measured by inductively coupled plasma optical emission spectrometry as 2.5, 2.56, and 3.5% for ZnO-SBA-1.0, ZnO-SBA-1.5, and ZnO-SBA-2.0, respectively. The size of inhibition of SBA-15, ZnO-SBA-0, ZnO-SBA-1.0, ZnO-SBA-1.5, and ZnO-SBA-2.0 were 0, 1.14 ± 0.01, 2.56 ± 0.01, 2.58 ± 0.01, and 2.69 ± 0.02 cm, respectively. ZnO-SBA-15s suppressed the growth of Escherichia coli compared to blank SBA-15 in a ZnO dose-dependent manner.

Enhanced photocatalytic activity of metal coated ZnO nanowires.

A simple, facile and template free route has been described for the synthesis of ZnO nanowires. The morphology and structure of ZnO nanowires have been tuned by deposing silver and gold onto the surface of ZnO nanowire and this has been done by adding AgNO(3) and HAuCl(4) to aqueous suspension of ZnO. Our synthesized Ag and Au coated ZnO nanoparticles show different emissive property than the native ZnO nanowires. The photocatalytic degradation of Methylene Blue is also evaluated using ZnO and Ag and Au coated ZnO nanowires. It has been observed that Ag coated ZnO nano-needles exhibits significantly enhanced photocatalytic efficiency compare to ZnO nanowire and Au coated ZnO nano-leaves. Fluorescence spectra and surface structure of the samples with their photocatalytic activity indicates that surface deposited metal serves as an electron sinks to enhance the separation of photoinduced electrons from holes, leading to the formation of OH and it enhances their photocatalytic efficiency.