Green approach to synthesize nano zinc oxide via Moringa oleifera leaves for enhanced anti-oxidant,anti-acne and anti-bacterial properties for health & wellness applications

This article explores green synthesis as a strategic and sustainable route to fabricate potent zinc oxide nanoparticles. Natural green based antibacterial agents and alternatives are being introduced in the market however there is a dearth in green approach moringa based zinc oxide nanoparticles in personal care products and establishing efficacy. Moringa oleifera comprises various phytochemicals that act as non-toxic stabilizing and reducing agents. Green synthesized ZnO nanoparticles (GsZnO-Nps) were investigated for their morphological and physicochemical properties using various advanced characterizing techniques. The hexagonal wurtzite structure of GsZnO-Nps is determined by X-ray diffractometry (XRD), the average crystallite size is 13.82 nm, total crystallinity was 95.91 % and high specific-surface-area is 77.38 m²/g. Scanning Electron Microscope (SEM) revealed the formation of spherical nanoparticles having a diameter of 50 nm. UV–vis spectrum shows high bandgap energy of 3.36 eV. Results have shown that antioxidant efficacy of GsZnO-Nps is significantly higher than AR-Grade ZnO, evaluated by using 2, 2-diphenyl-1-picrylhydrazyl (DPPH) assay. Half-maximal inhibitory concentration (IC₅₀) of GsZnO-Nps was 21.72 µg/mL and AR-Grade ZnO was 345.57 µg/mL. GsZnO-Nps (0.0183 g/mL) shows robust anti-acne efficacy against Cutibacterium acne (C. acne) organism which estimated by ZOI technique, have average ZOI of 33 mm, with standard error 0.577 mm. Antibacterial efficacy of GsZnO-Nps was established at different concentrations (10, 50, 100, and 200 µg/mL) against Gram-positive and Gram-negative pathogens by zone-of-inhibition (ZOI) method with respect to standard drugs. GsZnO-Nps at 200 µg/mL exhibits high ZOI of 26.75 mm against Escherichia coli (E. coli) and ZOI of 30 mm against Staphylococcus aureus (S. aureus) organisms respectively which is comparatively higher or equal to standard drugs. The minimum inhibitory concentration (MIC) of GsZnO-Nps is 500 µg/mL to inhibit the microbe's growth. GsZnO-Nps established the added benefits of moringa phytochemicals and is an excellent approach to developing eco-friendly and multi-functional versatile products having strong antioxidants, anti-acne and advanced antibacterial efficacy for numerous industrial applications like cosmetic, health hygiene products, drugs, therapeutic etc.     

A novel approach for fabrication ZnO/CuO nanocomposite via laser ablation in liquid and its antibacterial activity

Pulsed laser ablation in liquid (PLAL) has verified its surpassing advantages in the fabrication of several high purity nanostructured metals and metal oxides. In this work, ZnO/CuO heterostructure nanocomposites have been fabricated by laser ablation a Q switched Nd: YAG laser beam (1064 nm, 10 Hz, pulse energy and pulse with 30 mJ and 10 ns) is focused on the surface of the ZnO thin film for 10 min. The fabricated ZnO/CuO nanocomposite was then characterized using transmission electron microscopy (TEM), UV–vis spectrophotometer, X-ray diffraction (XRD), and Raman spectroscopy to investigate the structural, compositional, and optical properties of the fabricated nanocomposite. The synthesized nanocomposites were evaluated as antibacterial agents against both the gram-positive bacterium S. aureus subsp. aureus ATCCBAA-977, and the gram-negative bacteria E. coli ATCC8739, K. pneumoniae subsp. pneumoniae ATCC700603, and P. aeruginosa ATCC27853. The as-fabricated ZnO/CuO nanocomposite demonstrated outstanding antibacterial activity except in the case of K. pneumoniae subsp. pneumoniae ATCC700603 while the maximum activity was observed against E. coli ATCC8739.     

Green synthesis of RGO-ZnO mediated Ocimum basilicum leaves extract nanocomposite for antioxidant,antibacterial, antidiabetic and photocatalytic activity

Green chemistry of nanomaterials from synthesis to diverse biomedical applications is a discussion of town in the current scientific scenario. In this work, Ocimum basilicum leaves extract was utilized as the reducing agent in the synthesis of ZnO nanoparticles. Green synthesized ZnO NPs mediated via Ocimum basilicum extract were decorated on the reduced graphene oxide (RGO) sheet by the simple one-step method. The prepared green synthesized RGO-ZnO nanocomposites (NCs) were characterized via the X-ray diffractometer. The average crystallite size of ZnO was 25 nm which confirmed the wurtzite hexagonal structure of ZnO. The scanning Electron Microscopy technique confirmed the spherical morphology of particle size of 31 nm. Further, Fourier Transform Infrared Spectroscopy confirms the Zn-O bond stretching in the RGO-ZnO NCs. Antioxidant activity of the green synthesized Ocimum basilicum ZnO NPs and RGO-ZnO NCs were performed by DPPH scavenging activities and found the dose-dependent. RGO-ZnO effectively inhibited the α-amylase and α-glucosidase for in vitro antidiabetic activities. Moreover, RGO-ZnO NCs showed the antibacterial potential with increasing concentration against the gram-positive (Cocci) and gram-negative (E. coli) bacterial strains. In Photocatalytic activity, the ZnO NPs and RGO-ZnO NCs were utilized as the catalyst and degraded the Rh-B dye 91.4% and 96.7% under UV–visible light. Overall, RGO-ZnO NCs showed better results in antibacterial, antidiabetic activity as well as photocatalytic activity against the pure ZnO NPs. Hence, RGO-ZnO nanocomposites have demonstrated the opportunity to be an entrancing material for photocatalysis and biological studies.     

Efficient photodegradation of methyl orange and bactericidal activity of Ag doped ZnO nanoparticles

In the present work, silver-doped ZnO (Ag–ZnO NPs) with different concentrations of silver ions (0.3, 0.5, 1.0 and 1.5 mol %) were synthesized by using a simple co-precipitation method. The Ag–ZnO NPs were primarily characterized by XRD, FT-IR, SEM, EDS, TEM, UV–Vis. DRS, PL and BET surface area. The XRD analysis of Ag–ZnO NPs shows a wurtzite structure and optimized Ag–ZnO NPs (1.0 mol %) exhibit a lower crystallite size of 15.96 nm than that of bare ZnO (19.07 nm). Optical study shows a decrease in band gap from 3.13 to 2.97 eV as the concentration of Ag ions increases from 0.3 to 1.5 mol%. TEM images reveal the spherical shape particle with sizes ranging between 10 and 15 nm. From the multipoint BET plot, the surface area of Ag–ZnO NPs found 38.06 m²/gwhich is higher than the ZnO NPs (34.48 m²/g). The photocatalytic study demonstrated that the Ag–ZnO NPs (1.0 mol %) has an excellent photodegradation efficiency of Methyl Orange (96.74%)with a 26% increment as compared to bare ZnO (70.47%). Furthermore, the bactericidal activity of Ag–ZnO NPs (1.0 mol %) was investigated against four different bacterial strains. The results explored that the Gram-negative bacteria (E. coli and P. vulgaris) are more sensitive than Gram-positive (S. aureus and B. cereus) to Ag–ZnO NPs. Overall, the anticipated material is economical and reusable for photodegradation and antibacterial activity.     

Facile synthesis of ZnO and Co3O4 nanoparticles by thermal decomposition of novel Schiff base complexes: Studying biological and catalytic properties

In this paper, a novel Zn(II) and Co(II) Schiff base complexes were synthesized by template method via refluxing 2,3-Naphthalenedicarboxaldehyde, Metal(II) chloride (Metal = Zn or Co), and L-phenylalanine. ZnO and Co₃O₄ nanoparticles were synthesized by thermal decomposition of Zn(II) and Co(II) complexes, respectively. The products were characterized using different instruments such as CHN, Conductivity, FT-IR, XRD, HR-TEM, and UV–Vis spectrophotometer. The experimental results of elemental analysis for Zn(II) and Co(II) complexes, agree with the calculated results, indicating that the Zn(II) and Co(II) complexes have 1:1 ligand/metal ratios. The molar conductance of the Zn(II) and Co(II) complexes, is less than 5 Ω^?1cm^?1mol^?1, confirming the non-electrolytic nature of the synthesized complexes. The average crystallite diameter of the ZnO and Co₃O₄ samples is 39.64 and 30.38 nm, respectively. The optical energy gap of the ZnO and Co₃O₄ samples are 2.75 and 3.25 eV, respectively. Methylene blue dye was utilized to examine the photocatalytic properties of the synthesized nanoparticles using UV irradiations in the absence and presence of hydrogen peroxide. The % degradation of the methylene blue dye in the presence of hydrogen peroxide using ZnO and Co₃O₄ samples after 40 min is 94.55 and 98.98, respectively. Six pathogenic microbes were utilized to examine the antimicrobial properties of the synthesized Schiff base complexes and their nanoparticles: Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Streptococcus species, Aspergillus species, and Candida species. Zn(II) and Co(II) complexes display inhibition towards all the studied microbes. Besides, ZnO and Co₃O₄ nanoparticles exhibit less inhibition towards Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, and Streptococcus species. Moreover, ZnO and Co₃O₄ nanoparticles have no activity towards Aspergillus and Candida species.     

Jute stick extract assisted hydrothermal synthesis of zinc oxide nanoflakes and their enhanced photocatalytic and antibacterial efficacy

In this paper, we used green and hydrothermal methodology to prepare zinc oxide (ZnO) nanoflakes (NFs) with jute stick extract (J–ZnO NFs) as growth substrate. The prepared materials were characterized using different analytical techniques including ultraviolet–visible spectroscopy (UV–vis), X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), thermogravimetric analysis (TGA), fourier transform infrared (FTIR) spectroscopy, and X-ray photoelectron spectroscopy (XPS). The characteristic absorption peak for ZnO NFs and J–ZnO NFs were observed from the UV–vis spectrum at 373 and 368 nm respectively. The hexagonal wurtzite crystal structure of ZnO NFs and J–ZnO NFs was confirmed by XRD analysis. FESEM and TEM analyses of synthesized J–ZnO NFs confirmed their NFs shape and collectively flower-like structure formation by the assembly of NFs of J–ZnO on cellulose of jute stick extract substrate. The FTIR analysis revealed the functional groups of jute stick extract biomolecules, mainly cellulose, are responsible for the formation of collectivel flower like J–ZnO NFs structure. The XPS analysis revealed the surface and chemical compositions (Zn, C, and O) of J–ZnO NFs. The photocatalytic performance of ZnO NFs and J–ZnO NFs samples was carried out by the degradation of methylene blue (MB) dye solution under UV light irradiation. The degradation efficiency of ZnO NFs and J–ZnO NFs was obtained 79 % and 89 %, respectively, for 5 h. Notably, the degradation efficiency of the J–ZnO NFs was 98 % after 8 h of irradiation, which is very inspiring. The both NFs exhibited first-order kinetics with MB photodegradation. We also examined the possible antibacterial activity of both samples against Escherichia coli (E. coli) pathogens, which demonstrated a significant result with a 17 mm and 19 mm zone of inhibition by ZnO NFs and J–ZnO NFs respectively.     

Antibacterial polyethylene - Ethylene vinyl acetate polymeric blend by incorporation of zinc oxide nanoparticles

In this work, a Low-Density Polyethylene (LDPE) - Ethylene Vinyl Acetate (EVA) polymeric blend with antimicrobial activity was obtained. The main objective was to develop an antibacterial LDPE-EVA polymeric blend from the incorporation of antibacterial nanoparticles to increase the antimicrobial and sanitary safety of this polymeric blend when applied in the manufacture of medical products. The antibacterial activity was obtained from the incorporation of zinc oxide nanoparticles (ZnO-NPs) in the LDPE-EVA polymeric blends and the thermal properties were evaluated by differential scanning calorimetry and the mechanical properties by tensile stress tests for different percentages of ZnO-NPs. Scanning electron microscopy was used to study the morphological characteristics of the ZnO-NPs and also the characteristics of the distribution of nanoparticles in the polymer blends. The dispersive energy of x-ray fluorescence spectroscopy was used to study the chemical composition of the nanoparticles. Microbiological tests were performed to evaluate the antibacterial activity of the LDPE-EVA polymeric blends without and with ZnO-NPs against the bacteria Staphylococcus aureus (gram-positive) and Escherichia coli (gram-negative). The results obtained were excellent for the future application of the antibacterial LDPE-EVA polymeric blends to the manufacture of medical products. The Young's modulus values decreased and the tensile strength values showed small reductions and the thermal properties of the LDPE-EVA were not modified. However, the antibacterial activity of LDPE-EVA with 4 wt% of ZnO-NPs was excellent, eliminating the gram-positive bacteria in just 2 h and the gram-negative bacteria in just 2.5 h on their surfaces.     

Biosynthesis of ZnO nanoparticles through extract from Prosopis juliflora plant leaf: Antibacterial activities and a new approach by rust-induced photocatalysis

Rust-induced photocatalytic and antibacterial activities of ZnO nanoparticles derived from Prosopis juliflora leaf extracts by biosynthesis using the hydrothermal method at 170 °C are reported in this study. The characterization has been accomplished by various methods such as XRD, DRS, FT-IR, SEM, TEM, EDAX, and PL spectra. XRD exhibits that ZnO has a hexagonal wurtzite structure with a preferred orientation of 101 planes. The functional groups, which are present in the leaf extracts, are responsible for corresponding peaks in FT-IR spectra. The FESEM images of the synthesized nanoparticles show the morphology sphere like structure. ZnO particle size of 65 nm has been observed from HR-TEM analysis. The elemental composition has a good agreement with the biosynthesized ZnO nanoparticles. The antibacterial activities have been carried out in vitro assays against four different pathogens viz Escherichia coli (E. coli), Rhodococcus rhodochrous (R. rhodochrous), Bacillus subtilis (B. subtilis) and Vibrio cholera (V. Cholera) against a standard (streptomycin sulfate). Furthermore, the Photocatalytic ability of the titled nanoparticles has been experimented from the rust solution with methylene blue and degradation under UV radiation of 99%. The proposed mechanism is based on scavenger studies and it is investigated during the photo degradation of Methylene blue. The catalytic amount and recovery of photocatalyst have also been studied in detail.     

离子液体中纤维素/纳米层状ZnO复合抗菌纤维的制备及性能

以表面活性剂十二烷基磺酸钠(SDS)为模板,Zn(NO_3)_2·6H_2O和NaOH为锌源和沉淀剂,通过改进的模板法在温和条件下制得纳米层状ZnO.以离子液体1-烯丙基-3-甲基咪唑氯盐([Amim]Cl)为溶剂,木浆纤维素和纳米层状ZnO为原料,采用溶液共混方法,通过干湿法纺丝制备了ZnO质量分数分别为3%,5%,7%及9%的纤维素/ZnO纳米复合纤维.采用X射线衍射(XRD)、X射线光电子能谱(XPS)、透射电子显微镜(TEM)、场发射扫描电子显微镜(SEM)及热重分析(TG)等方法对纳米层状ZnO及纤维素/ZnO复合纤维进行了表征,并探讨了ZnO的加入对复合体系流变性的影响,同时对复合纤维进行了力学和抗菌性能测试.研究结果表明,所制备氧化锌纯度高,且呈现出重复周期为3.58 nm的层状结构,抗菌性能优异.纳米层状ZnO的加入提高了纤维素纤维的热稳定性和机械强度,同时赋予纤维对金黄色葡萄球菌和大肠杆菌的抑菌性.ZnO片层被纤维素链剥离,并均匀分散于纤维素/ZnO复合物中.ZnO的加入增大了纤维素溶液的黏度,当ZnO含量达到5%以上时,在整个频率范围内,弹性模量大于损耗模量,纳米粒子可稳定悬浮.     

Broad spectrum antibacterial zinc oxide-reduced graphene oxide nanocomposite for water depollution

Antimicrobial-resistance (AMR) is a global health challenge arising from the evolution of bacteria, viruses, fungi, and parasites, such that pathogenic microorganisms no longer respond to classical therapies. AMR and the rise of so-called ‘superbugs’ requires innovative nanomaterials and biostatic strategies. Here we report a broad spectrum, antimicrobial nanomaterial integrating light-responsive ZnO nanoparticles (NP) and reduced graphene oxide (rGO) into a heterojunction semiconductor nanocomposite for water depollution. Simultaneous chemical reduction of Zn sulphate and GO sheets yields a low concentration (0.5 mol%) of 10 nm ZnO nanoparticles decorating fragmented rGO nanosheets, with a total surface area of 12 m²/g and optical band gap of 1.6 eV. Antimicrobial performance of the ZnO-rGO nanocomposite was evaluated against methicillin-resistant Staphylococcus aureus (MRSA), Escherichia coli 0157:H7 and Salmonella typhimurium bacteria, which are prevalent in contaminated aquatic systems; antimicrobial efficacy against these organisms was 96%, 97%, and 73%, respectively, for a loading of 2 mg/mL, evidencing a strong synergy compared with pure ZnO or rGO components. ZnO-rGO was also an effective photocatalyst for the aqueous degradation of Malachite Green dye, suggesting that its mode of antibacterial action reflects the production of reactive oxygen species under ambient illumination.     

Formulation,characterization and biological evaluation of injectable nanocrystals from stem exudate gel of Caralluma retrospiciens (Ehrenb) – Part C

The purpose of this study was to develop injectable nanocrystals (NC) from stem exudate gel (EG) from Caralluma retrospiciens (Ehrenb) using the technique of nanoprecipitation. The NC had a zeta potential of ?5.58 ± 4.27 mV. Size distribution analysis showed that it ranged in size from 100 to 300 nm. The polydispersity index (PDI) was 0.467, while its percentage PDI was 68.4. Scanning electron microscopic analysis and transmission electron microscopy studies revealed the morphological features of NC as discrete crystals with rough surfaces. The mobility of NC was 5.5 µm.cm/Vs, while its conductivity was 0.16 mS/cm. Antibacterial studies showed broad activity against both Gram-positive and Gram-negative bacteria. The minimum inhibitory concentrations (MICs) of NC against Bacillus subtilis (B. subtilis), Staphylococcus aureus (S. aureus), Streptococcus pyogenes (S. pyogenes), Escherichia coli (E. coli), Pseudomonas aeruginosa (P. aeruginosa) and Klebsiella pneumoniae (K. pneumoniae) were 6, 8, 8, 4, 8, and 6 % (w/v), respectively. The antibacterial effect was highest against K. pneumoniae (25.6 ± 1.5 mm), followed by E. coli (25.5 ± 1.8 mm), P. aeruginosa (24.1 ± 1.2 mm), S. pyogenes (22.2 ± 1.2 mm), S. aureus (21.83 ± 1.2 mm) and B. subtilis (20.33 ± 1.8 mm). In this study, the cytotoxicity properties of NC were determined against MCF-7 breast cancer cells ATCC. The NC failed to inhibit the proliferation of MCF-7 cells against the even at 300 µg/mL concentration. These results indicated that the NC is a promising antibacterial injectable dosage form.     

Synthesis,characterization and application of Cr2O3 nanoparticles as an efficient antibacterial agent

This study focuses on the microwave-assisted synthesis of Cr₂O₃ nanoparticles for the development of antibacterial materials. Characterization techniques including FT-IR spectroscopy, UV–vis spectroscopy, SEM-EDX, and XRD, were employed to analyze the nanoparticles' properties. The antibacterial efficacy against E. coli, S. aureus, B. subtilis, and P. aeruginosa was evaluated, with significant activity observed against all pathogens, highlighting their potential as antibacterial materials. The novelty of this study lies in the synthesis of Cr₂O₃ nanoparticles and their application as potent antibacterial agents against various pathogens. The results of XRD study concludes the average size of Cr₂O₃ nanoparticles as 49.96 nm. The synthesized Cr₂O₃ nanoparticles demonstrated a good zone of inhibition against E. coli (22 mm), S. aureus (19 mm), B. subtilis (18 mm), and P. aeruginosa (21 mm). The findings of the study suggest that Cr₂O₃NPs have potential as a novel antibacterial agent, and further research in this area could lead to the development of new and effective treatments for bacterial infections.     

Aggregation-induced emission-active antibacterial hydrogel with self-indicating ability for real-time monitoring of drug release process

Although antibacterial hydrogels are emerging as promising biomaterials for effective inhibition of bacterial infections, monitoring their dynamic release behaviors in a visual manner remains greatly challenging. Herein, non-conjugated luminescent polymers (NCLPs) with aggregation-induced emission (AIE) characteristics are used for the first time to develop a visualization strategy to monitor the release process of the drug-loaded hydrogel. The novel antimicrobial peptide polymers with intrinsic AIE effect, namely nanoengineered peptide-grafted hyperbranched polymers (NPGHPs), are encapsulated in an anionic polyelectrolyte to construct the AIE-active fluorescent polymeric hydrogel (NPGHPs/SA gel). Interestingly, the rigid environment mediated by hydrogen bonding and electrostatic interaction contributes to promoting the unconventional luminescence of fluorescent clusters. Moreover, the successive drug release process of NPGHPs/SA gel can be tracked in real time by using fluorescence microscopy. The hydrogel also has potent antibacterial activities against Gram-negative bacteria (E. coli, P. aeruginosa) and Gram-positive bacteria (S. aureus, B. subtilis). Overall, this work not only provides an advanced biomedical material with broad-spectrum antibacterial ability but also opens a facile avenue up for the investigation of drug release from gel systems.     

Structural,thermal, optical and conductivity studies of Co/ZnO nanoparticles doped CMC polymer for solid state battery applications

In this study, a simple chemical precipitation method was used to synthesize ZnO: Co²⁺ as nanoparticles. The solution casting technique was used for the preparation of polymer films of Carboxymethyl cellulose (CMC) doped with different contents (0.5, 1.5, 3, and 5 wt%) of ZnO/Co NPs. As shown by the X-ray diffraction, the average size of ZnO/Co crystallite of the NPs is 25.6 nm. Meanwhile, the addition of ZnO/Co reduced the semi-crystallinity of CMC. The Fourier transform infrared (FTIR) confirmed the interaction between the ZnO/Co NPs and the polymer CMC. The direct and indirect band gap (Eg) was reduced from (5.32–5.01 eV and 5.20 to 4.99 eV respectively) with the increase in ZnO/Co NPs content up to 3 wt% after this content the Eg is increased as shown by the UV–Vis spectra. In addition, the results of TGA displayed the decomposition of the nanocomposite to be little compared to that of the pure CMC indicating the success of fabrication of products. The improvement of the ionic conductivity was noticed upon the addition of ZnO/Co NPs into the polymer CMC system which can be explained in terms of an increase in amorphicity as shown by the impedance spectroscopic study. It was found that the optimum ionic conductivity (3.209 × 10⁻⁶ Scm⁻¹) at ambient temperature was higher for the sample containing 1.5 wt% ZnO/Co NPs with highest of amorphicity and the lowest total loss of weight. Therefore, the improvements in optical properties, thermal stability, and AC conductivity which were observed represent a strong support for the use of the nanocomposite films in the solid state battery applications.     

Profile characterization and biological activities of cold pressed Garden Cress (Lepidium sativum) seed oil

Lepidium sativum is cultivated mainly for the edible oil from its seeds, and considered as an unutilized and neglected crop despite its important properties. Its oil fraction is used to produce soap and stabilize linseed oil when it is mixed with wild mustard seed oil. Once converted into fatty acid methyl esters, it represents a good substitute for imported petroleum diesel after alkaline transesterification reaction. In the current study, Lepidium sativum seeds cultivated in Tunisia and the physicochemical properties and nutrient profile of its cold pressed seed oil were investigated. The antioxidant, antibacterial, and anti-inflammatory activities of the above oil were also assessed. Lepidium sativum seed oil was abundant in both linolenic (35.59 ± 1.9%) and oleic (21.14 ± 0.63%) acids, and high amounts of β-sitosterol (42.57 ± 2.96 mg/100 g), campesterol (20.04 ± 1.4 mg/100 g) and Δ 5,24 stigmastadienol (11.82 ± 0.45 mg/100 g) were detected. The total tocopherol content of Lepidium sativum seed oil reached 136.83 ± 7.6 mg/100 g with a predominance of γ-tocopherol (86.23%). Its seed oil exhibited an IC₅₀ of 10.33 ± 0.05 mg/mL and a radical scavenging activity of 415.6 ± 40 Trolox Equivalent Antioxidant Capacity (TEAC) for the DPPH and the ABTS assays, respectively. While the thermal analysis proved a high thermal stability of Lepidium sativum seed oil, that of eight bacteria and one fungal strain showed no noticeable bacterial or antifungal effects. It was also revealed that Lepidium sativum seed oil held a remarkable anti-inflammatory activity. Hence, the obtained results evidenced remarkable chemical, antioxidant and anti-inflammatory properties of Lepidium sativum seed oil, which might potentially be promising for enhancing human health and preventing age-related diseases.     

The surface modification of spherical ZnO with Ag nanoparticles: A novel agent,biogenic synthesis,catalytic and antibacterial activities

Nowadays, the industrial wastewater pollutants including toxic dyes and pathogenic microbes have caused serious environmental contaminations and human health problems. In the present study, eco-friendly and facile green synthesis of Ag modified ZnO nanoparticles (ZnO-Ag NPs) using Crataegus monogyna (C. monogyna) extract (ZnO-Ag@CME NPs) is reported. The morphology and structure of the as-biosynthesized product were characterized by field emission scanning electron microscopy (FESEM), X-Ray diffraction (XRD), differential reflectance spectroscopy (DRS), dynamic light scattering (DLS), transmission electron microscopy (TEM), Fourier-transform infrared spectroscopy (FT-IR), and energy-dispersive X-ray spectroscopy (EDS) techniques. TEM and FESEM images confirmed the oval and spherical-like structure of the products with a size of 55–70 nm. The EDS analysis confirmed the presence of Zn, Ag, and O elements in the biosynthesized product. The photocatalytic results showed ZnO-Ag@CME NPs were degraded (89.8% and 75.3%) and (94.2% and 84.7%) of methyl orange (MO) and basic violet 10 (BV10), under UV and sunlight irradiations, respectively. The Ag modified ZnO nanoparticles exhibited enhanced catalytic activity towards organic pollutants, and showed better performance than the pure ZnO nanoparticles under UV and sunlight irradiations. This performance was probably due to the presence of silver nanoparticles as a plasmonic material. Antibacterial activity was performed against different bacteria. ZnO-Ag@CME NPs showed high antibacterial activity against K. pneumoniae, S. typhimurium, P. vulgaris, S. mitis, and S. faecalis with MIC values of 50, 12.5, 12.5, 12.5, and 12.45 µg/mL, respectively. All in all, the present investigation suggests a promising method to achieve high-efficiency antibacterial and catalytic performance.     

Zein films with ZnO and ZnO:Mg quantum dots as functional nanofillers: New nanocomposites for food package with UV-blocker and antimicrobial properties

The preparation of a new nanocomposite by combining zein and quantum dots (QDs) was the main interest of the present work. By the sol-gel method, colloidal ethanolic dispersions of zinc oxide (ZnO) particles and ZnO particles doped with magnesium (II) (ZnO:Mg) were obtained, sized 4.26 and 3.65 nm, respectively, as determined by UV–Vis spectroscopy. The prepared QDs were used as nanofillers in order to obtain zein-based nanocomposite films, which displayed good visual appearance, homogeneity, and transparency. The presence of QDs increased the hydrophobicity and reduced, up to three times, the amount of water uptake of the composite films when compared to pure zein. Those effects were more pronounced for ZnO:Mg QDs. TEM, FTIR, and fluorescence microscopy analysis indicated that zein interacts more effectively with ZnO:Mg than with ZnO. In addition, and most importantly, the presence of QDs in the films showed an important advantage when compared to those of pure zein: the extended UV-blocking in the absorbance spectra. The antimicrobial assays demonstrated that the ZnO NPs, loaded into zein films, are promising antibacterial materials since the inhibition of growth of S. aureus reached (96.5 ± 4.9)% at 44.8 wt% of ZnO NPs. Therefore, the nanocomposites show promising features for the development of food packaging, UV protective films, and for the development of new and sustainable materials.     

Preparation and characterization of novel polyimide/functionalized ZnO bionanocomposite for gas separation and study of their antibacterial activity

In the present investigation novel Polyimide/functionalized ZnO (PI/ZnO) bionanocomposites containing amino acid (Methionine) and benzimidazole pendent groups with different amounts of modified ZnO nanoparticles (ZnO NPs) were successfully prepared through ultrasonic irradiation technique. Due to the high surface energy and tendency for agglomeration, the surface ZnO NPs was modified by a coupling agent as 3- methacryloxypropyl-trimethoxysilane (MPS) to form MPS-ZnO nanoparticles. The ultrasonic irradiation effectively changes the rheology and the glass transition temperature and the crystallinity of the composite polymer. PI/ZnO nanocomposites were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscope (TEM). TEM analysis showed that the modified ZnO nanoparticles were homogeneously dispersed in polymer matrix. The TGA results of PI/ZnO nanocomposites showed that the thermal stability is obviously improved the presence of MPS-ZnO NPs in comparison with the pure PI and that this increase is higher when the NP content increases. The permeabilities of pure H₂, CH₄, O₂, and N₂ gases through prepared membranes were determined at room temperature (25 °C) and 20 bar feed pressure. The membranes having 20% ZnO showed higher values of H₂ permeability, and H₂/CH₄ and H₂/N₂ ideal selectivities (the ratio of pair gas permeabilities) compared with other membranes. The antibacterial activity of bionanocomposite films was tested against gram-positive bacteria (Staphylococcus aureus and Bacillus subtilis) and gram-negative bacteria (Escherichia coli and Pseudomonas aeruginosa). Further, it was observed that antibacterial activity of the resulting hybrid biofilms showed somewhat higher for gram-positive bacteria compared to gram-negative bacteria.     

Investigation of structural,optical and photoluminescence properties of non-essential amino acid capped zinc sulfide nanoparticles for optoelectronic applications

The objective of the study is to synthesize Zinc Sulphide nanoparticles (ZnS) with different amino acid capping agents in aqueous solution by a simple and cost effective facile chemical co precipitation method and analyze their optoelectronic features. Bio compatibility with less toxic amino acids such as l-Glutamic acid, l-Alanine and l-Asparagine were used as capping agents. These amino acids are from Non-essential amino acid group and its capping behavior suitable for semiconducting nanoparticles like ZnS. The role of non essential amino acids were to stabilize the nanoparticle against agglomeration and also to provide chemical passivation that leads to a significant influence on the improved structural, optical and photoluminescence properties of ZnS nanoparticles. The detailed structural analysis of Zinc Sulphide nano particles revealed by X-ray diffraction method (XRD). From this analysis observed the formation of Cubic ZnS nanoparticles with an average crystallite size in the range of 2.08–2.22 nm.The morphology of the nano particles studied by Field emission scanning electron microscope (FESEM). Particle size examined by Dynamic Light scattering studies (DLS) and which revealed that particle size ranges are below 50 nm. The functional groups of nanoparticles were identified by Fourier transform Infrared spectroscopy (FT-IR) studies. Photoluminescence studies attributed that the considerable emission bands. The UV–Vis analysis disclosed the optical band gap range from 3.77 eV to 3.95 eV.     

Construction of crosslinking network structures by adding ZnO and ADR in intumescent flame retardant PLA composites

Different proportion of nano zinc oxide (nano ZnO) and chain extender (ADR) were combined with the intumescent flame retardant and then added into the PLA matrix. The thermal stability, flame retardant performance, and mechanical properties were studied. The gel content results showed that crosslinking structures were obtained after the addition of nano ZnO and ADR, which were generated by the catalytic chain scission effect of nano ZnO and chain extension effect of ADR. With addition of 1% nano ZnO and 1.6% ADR, the gel content of flame retardant PLA composite reached the highest value (14.2%). Meanwhile, the corresponding flame retardant PLA composite with 1% nano ZnO and 1.6% ADR, named FRPLA/ZnO/ADR-1, exhibited an overall improved properties including the flame retardant properties and mechanical performance, which passed the UL94 V-0 level with a limiting oxygen index value of 40.1%. Compared to FRPLA (flame retardant PLA without ZnO and ADR), the peak heat release rate and the total smoke production of FRPLA/ZnO/ADR-1were reduced by 60% and 67% respectively, and the final mass improved from 12% to 38%. In addition, the tensile strength and elongation at break of FRPLA/ZnO/ADR-1 increased by 25%, 14% compared with that of FRPLA. The impact strength was 15.1 kJ/m², which is similar to the pure PLA (15.6 kJ/m²). It indicated that the addition of nano ZnO and ADR could balance the flame retardant performance and the mechanical properties of the flame retardant PLA.