Investigation of the Characteristics and Antibacterial Activity of Polymer-Modified Copper Oxide Nanoparticles

The proliferation of drug-resistant pathogens continues to increase, giving rise to serious public health concerns. Many researchers have formulated metal oxide nanoparticles for use as novel antibacterial agents. In the present study, copper oxide (CuO) was synthesized by simple hydrothermal synthesis, and doping was performed to introduce different polymers onto the NP surface for bacteriostasis optimization. The polymer-modified CuO NPs were analyzed further with XRD, FTIR, TEM, DLS and zeta potential to study their morphology, size, and the charge of the substrate. The results indicate that polymer-modified CuO NPs had a significantly higher bacteriostatic rate than unmodified CuO NPs. In particular, polydopamine (PDA)-modified CuO (CuO-PDA) NPs, which carry a weakly negative surface charge, exhibited excellent antibacterial effects, with a bacteriostatic rate of up to 85.8 ± 0.2% within 3 h. When compared to other polymer-modified CuO NPs, CuO-PDA NPs exhibited superior bacteriostatic activity due to their smaller size, surface charge, and favorable van der Waals interactions. This may be attributed to the fact that the CuO-PDA NPs had relatively lipophilic structures at pH 7.4, which increased their affinity for the lipopolysaccharide-containing outer membrane of the Gram-negative bacterium Escherichia coli.     

Marine Collagen-Based Antibacterial Film Reinforced with Graphene and Iron Oxide Nanoparticles

It has become more widely available to use biopolymer-based films as alternatives to conventional plastic-based films due to their non-toxic properties, flexibility, and affordability. However, they are limited in application due to deficiencies in their properties. The marine collagen was the specimen for the present study. Thus, the main objective was to reinforce marine collagen-based films with 1.0% (w/w of the dry polymer weight) of iron oxide nanoparticles (IO-NPs), graphene oxide nanoparticles (GO-NPs), or a combination of both oxides (GO-NPs/IO-NPs) as antibacterial and antioxidant additives to overcome some of the limitations of the film. In this way, the nanoparticles were incorporated into the film-forming solution (2% w/v in acetic acid, 0.05 M) and processed by casting. Thereafter, the films were dried and analyzed for their physicochemical, mechanical, microstructural, and functional properties. The results show that the effective combination of GO-NPs/IO-NPs enhanced the physicochemical properties by increasing the water contact angle (WCA) of the films from 77.2 to 84.4° and their transparency (T) from 0.5 to 5.2. Furthermore, these nanoparticles added antioxidant and antibacterial value to the films, with free radical inhibition of up to 95.8% and 23.8 mm of bacteria growth inhibition (diameter). As a result, both types of nanoparticles are proposed as suitable additives to be incorporated into films and enhance their different properties.     

Nanoarchitectonics of Hydroxyapatite/Molybdenum Trioxide/Graphene Oxide Composite for Efficient Antibacterial Activity

Nanocomposites based on hydroxyapatite (HAP), including MoO₃, HAP/MoO₃, HAP/GO and HAP/MoO₃/GO have been studied to be suggested for biological usage. The different compositions were investigated using FTIR, XRD, EDS, and XPS analysis. The tight relation between morphological features and composites' chemical ingredients was also studied. According to TEM micrographs, it was mentioned that the disappearance of well-defined grains after the combinations of HAP and MoO₃, while graphene oxide (GO) caused a reduction in size and maintaining the particles’ shape. The combination between HAP/MoO₃ declines the roughness of both HAP and MoO₃ individually, recording 27.5 nm, while HAP/GO and HAP/MoO3/GO exhibit in-between roughness average (Ra) value among its raw constituents with 34.7 and 33.5 nm, respectively. Furthermore, SEM micrographs and roughness results show how to tailing the proper features for the proposed application by changing the type and amount of additives into HAP. Thus, the composite (HAP/MoO₃/GO) displays the uppermost cell viability compared with the rest compositions with 97.8?±?3.0%. Additionally, this triple composite hits the peak germicidal behavior with 17.9?±?1.2 and 16.5?±?0.9 mm against both E.coli and S.aureus, respectively.

     

Removal of Chromium(VI) Using Surface Modified Superparamagnetic Iron Oxide Nanoparticles

This study describes the removal of Chromium(VI) from aqueous solutions using surface tailored superparamagnetic iron oxide nanoparticles (SPION) coated with bis(2,4,4-trimethylpentyl)dithiophosphinic acid (Cyanex-301). The synthesized Cyanex-301 coated SPION has been characterized by Transmission Electron Microscopy (TEM), Fourier-Transfer Infrared Spectroscopy (FT-IR), X-ray Photonic Spectroscopy (XPS), and Thermogravimetric Analysis (TGA). The adsorption mechanism was proposed to be via complexation between the thiol group on Cyanex-301 and Cr(VI) ions based on the XPS and FTIR analysis. It has been found that the equilibrium can be attained in less than 2 hr. The adsorption behavior of Cr(VI) on the Cyanex-301 coated SPION can be well described by the Langmuir model and the maximum adsorption capacity for Cr(VI) was estimated to be 30.8 mg/g. The selectivity of the Cyanex-301 coated SPION adsorbent towards Cr(VI) ions was found to be high and the maximum loading capacity obtained is up to an order of magnitude higher than that of other adsorbents reported in the literature. The desorption studies showed that more than 70% of Cr(VI) can be recovered using HNO₃ as eluting solution. Our findings suggest a high potential of the designed adsorbent material for the treatment of industrial wastewater containing Cr(VI).     

The Antibacterial Activity of Ta-doped ZnO Nanoparticles

A novel photocatalyst of Ta-doped ZnO nanoparticles was prepared by a modified Pechini-type method. The antimicrobial study of Ta-doped ZnO nanoparticles on several bacteria of Gram-positive Bacillus subtilis (B. subtilis) and Staphylococcus aureus (S. aureus) and Gram-negative Escherichia coli (E. coli) and Pseudomonas aeruginosa (P. aeruginosa) were performed using a standard microbial method. The Ta-doping concentration effect on the minimum inhibitory concentration (MIC) of various bacteria under dark ambient has been evaluated. The photocatalytical inactivation of Ta-doped ZnO nanoparticles under visible light irradiation was examined. The MIC results indicate that the incorporation of Ta⁵⁺ ions into ZnO significantly improve the bacteriostasis effect of ZnO nanoparticles on E. coli, S. aureus, and B. subtilis in the absence of light. Compared to MIC results without light irradiation, Ta-doped ZnO and pure ZnO nanoparticles show much stronger bactericidal efficacy on P. aeruginosa, E. coli, and S. aureus under visible light illumination. The possible antimicrobial mechanisms in Ta-doped ZnO systems under visible light and dark conditions were also proposed. Ta-doped ZnO nanoparticles exhibit more effective bactericidal efficacy than pure ZnO in dark ambient, which can be attributed to the synergistic effect of enhanced surface bioactivity and increased electrostatic force due to the incorporation of Ta⁵⁺ ions into ZnO. Based on the antibacterial tests, 5 % Ta-doped ZnO is a more effective antimicrobial agent than pure ZnO.     

Trapping Iron Oxide into Hollow Gold Nanoparticles

Synthesis of the core/shell-structured Fe₃O₄/Au nanoparticles by trapping Fe₃O₄ inside hollow Au nanoparticles is described. The produced composite nanoparticles are strongly magnetic with their surface plasmon resonance peaks in the near infrared region (wavelength from 700 to 800 nm), combining desirable magnetic and plasmonic properties into one nanoparticle. They are particularly suitable for in vivo diagnostic and therapeutic applications. The intact Au surface provides convenient anchorage sites for attachment of targeting molecules, and the particles can be activated by both near infrared lights and magnetic fields. As more and more hollow nanoparticles become available, this synthetic method would find general applications in the fabrication of core–shell multifunctional nanostructures.     

水热法制备纳米氧化铁的研究

对水热法制备纳米氧化铁以及氧化氢氧化铁进行了研究。通过实验制得了多种不同形貌的纳米氧化铁以及纳米氧化氢氧化铁,利用X射线电子衍射(XRD)、透射电子显微镜(TEM)、扫描电子显微镜(SEM)对所得产物进行了表征,研究了反应时间、温度对最终产物形貌、粒径的影响,对产物的变化规律进行了总结。     

Novel Green Synthesis of Zinc Oxide Nanoparticles Using Orange Waste and Its Thermal and Antibacterial Activity

Journal of Inorganic and Organometallic Polymers and Materials - Zinc oxide nanoparticles (ZnO NPs) prepared via eco-friendly synthesis (using orange peels) are investigated. Pseudomonas Aeruginosa...     

Removal of As(III) from Aqueous Solution Using Functionalized Ultrafine Iron Oxide Nanoparticles

Arsenic toxicity has become a major concern worldwide. Remediation of this problem needs the development of technology with improved materials and systems with high efficiency. We have demonstrated a simple and efficient method for the absolute removal of As(III) from high concentration As(III) treated water with a low contact time period. The process of As(III) adsorption follows pseudo-second-order kinetic model. The mechanism for high-adsorption efficiency is attributed to fatty acid binding domain-mediated surface conjugation of ultrafine Fe₂O₃ nanoparticles with As(III). We have also ensured the simultaneous separation of arsenic sorbed nanoparticles by entrapping them in hydrophilic calcium alginate beads and thereby a pure arsenic free solution has been obtained.     

Preparation of Carbon Nanotubes Using Iron Oxide(III) Nanoparticles Size-Controlled by Phenylazomethine Dendrimers

Dendritic polyphenylazomethine (DPAG4) can precisely incorporate any number of metals onto the imine sites. After spin casting of the solution of the complex between DPAG4 and iron trichloride(III) (FeCl₃) on the substrate, iron oxide(III) nano dots could be prepared by hydrolysis of the complex fabricated on the substrate. The diameters and heights of the iron oxide could be controlled based on the molar amount of incorporated FeCl₃ in DPAG4. Using these iron oxide nano dots as the catalyst, we attempted to fabricate carbon nanotubes on the bare silicon substrate by reacting with a mixed gas at high temperature.     

Mutagenic Effects of Iron Oxide Nanoparticles on Biological Cells

In recent years, there has been an increased interest in the design and use of iron oxide materials with nanoscale dimensions for magnetic, catalytic, biomedical, and electronic applications. The increased manufacture and use of iron oxide nanoparticles (IONPs) in consumer products as well as industrial processes is expected to lead to the unintentional release of IONPs into the environment. The impact of IONPs on the environment and on biological species is not well understood but remains a concern due to the increased chemical reactivity of nanoparticles relative to their bulk counterparts. This review article describes the impact of IONPs on cellular genetic components. The mutagenic impact of IONPs may damage an organism’s ability to develop or reproduce. To date, there has been experimental evidence of IONPs having mutagenic interactions on human cell lines including lymphoblastoids, fibroblasts, microvascular endothelial cells, bone marrow cells, lung epithelial cells, alveolar type II like epithelial cells, bronchial fibroblasts, skin epithelial cells, hepatocytes, cerebral endothelial cells, fibrosarcoma cells, breast carcinoma cells, lung carcinoma cells, and cervix carcinoma cells. Other cell lines including the Chinese hamster ovary cells, mouse fibroblast cells, murine fibroblast cells, Mytilus galloprovincialis sperm cells, mice lung cells, murine alveolar macrophages, mice hepatic and renal tissue cells, and vero cells have also shown mutagenic effects upon exposure to IONPs. We further show the influence of IONPs on microorganisms in the presence and absence of dissolved organic carbon. The results shed light on the transformations IONPs undergo in the environment and the nature of the potential mutagenic impact on biological cells.     

Suspensions of Iron Oxide Nanoparticles Stabilized by Anionic Surfactants

Two common anionic surfactants, sodium oleate (SO) and sodium dodecyl benzene sulfonate (SDBS) were used to re‐suspend iron oxide nanoparticles in aqueous solutions. At certain SO concentrations, the SO formulations produced highly stable suspensions. In contrast, SDBS‐stabilized nanoparticles exhibited poor stability at all concentrations. The adsorption isotherm of SO on iron oxide nanoparticles revealed that stable suspensions were obtained when the equilibrium SO concentration (after adsorption) reached its critical micelle concentration (CMC). At this “optimal” condition, the maximum SO adsorption was reached, and the zeta‐potential of the particles was highly negative (～ ?50 mV). According to the SO isotherm, this optimal formulation coincided with the formation of a highly compact SO bilayer. The SDBS isotherm, on the other hand, revealed that SDBS is not strongly adsorbed on the surface of iron oxide nanoparticles and that is likely that a patchy, loosely packed bilayer, is formed on the surface of the iron oxide nanoparticles when the equilibrium SDBS concentration reaches its CMC. The DLVO theory confirmed the connection between formulation conditions and the corresponding stability. This works confirmed that the formation of a surfactant bilayer is an important element in producing stable nanoparticle suspensions with anionic surfactants. It was also confirmed that for anionic surfactants, electrostatic repulsions are an important factor in establishing an energy barrier against flocculation. This work also introduced two more elements into the design of nanoparticle suspensions. The first element is that, in order to ensure the best possible dispersion, the surfactant concentration in solution at equilibrium with the adsorbed surfactant should be close or slightly above its CMC. The second element is that the molecular structure of the surfactant should facilitate the formation of closely packed bilayers.     

纳米氧化铁的制备及其掺杂效应

纳米氧化铁作为气敏材料得到广泛重视。本文重点介绍了近年来应用比较普遍的合成纳米氧化铁的方法,如:溶胶—凝胶法、共沉淀法、水热法、水解法,并指出了各种方法的优缺点;同时,介绍了在掺杂了不同的物质后纳米氧化铁具有的独特的气敏性能;最后,对氧化铁基气敏元件的烧成工艺进行了比较。     

油酸改性超顺磁性氧化铁纳米粒子的制备

以氯化亚铁和氯化铁为原料,通过共沉淀法制备了亲水性的超顺磁性氧化铁纳米粒子(SPION),然后对油酸的羧基进行活化,采用化学方法制备油酸改性超顺磁性氧化铁纳米粒子(O-SPION)。用XRD、FTIR、DLS、TEM对产物结构进行了表征,并通过MTT法检测了O-SPION对人肝癌细胞HepG2的毒性作用,普鲁士蓝染色法检测了其细胞摄取能力。结果表明:合成的O-SPION形态规则,其核心粒径为(12±1.5)nm,Zeta电位为(36±1.5)m V,可在有机溶剂中形成稳定的磁流体。体外细胞实验显示,当O-SPION质量浓度最高为800 mg/L时,O-SPION对HepG2细胞无明显毒性。普鲁士蓝染色图可见,O-SPION较未改性的SPION细胞摄取量明显增多。     

氧化铁磁性纳米粒子的表面修饰及应用

氧化铁磁性纳米粒子因其优异的性能,广泛应用于环境分离、生物活性物质的富集和分离等领域,近年来引起了广泛的关注和研究。文章总结了氧化铁肱性纳米粒子表面修饰方法及相关应用,并对其前号进行了展望。     

纳米氧化亚铜的制备及其抑菌性研究

采用简便易行的化学沉淀法制备了花簇状氧化亚铜,通过XRD、FE-SEM、BET等方法对其进行表征。以大肠杆菌为受试菌种,通过与立方体氧化亚铜对比,探究其抑菌过程,研究了比表面积对氧化亚铜抑菌性能的影响。此外,还探讨了氧化亚铜的抑菌机制。     

On the Enhanced Antibacterial Activity of Antibiotics Mixed with Gold Nanoparticles

The bacterial action of gentamicin and that of a mixture of gentamicin and 15-nm colloidal-gold particles on Escherichia coli K12 was examined by the agar-well-diffusion method, enumeration of colony-forming units, and turbidimetry. Addition of gentamicin to colloidal gold changed the gold color and extinction spectrum. Within the experimental errors, there were no significant differences in antibacterial activity between pure gentamicin and its mixture with gold nanoparticles (NPs). Atomic absorption spectroscopy showed that upon application of the gentamicin-particle mixture, there were no gold NPs in the zone of bacterial-growth suppression in agar. Yet, free NPs diffused into the agar. These facts are in conflict with the earlier findings indicating an enhancement of the bacterial activity of similar gentamicin–gold nanoparticle mixtures. The possible causes for these discrepancies are discussed, and the suggestion is made that a necessary condition for enhancement of antibacterial activity is the preparation of stable conjugates of NPs coated with the antibiotic molecules.     

高分散性纳米铁的制备及其表征

以可生物降解的聚苯乙烯磺酸钠(PSS)为分散剂,制备了能稳定分散于水中的零价纳米铁(nZⅥ).未改性的零价纳米铁呈规则的球形或椭球形,平均粒径为60～80 nm,经PPS分散后的纳米铁nZVI/PSS则呈现微小的粒状分散在PSS中.pH=8时,与nZVI相比,nZVI/PSS的ζ电位由+9.4 mV降至-36.7 mV,同时等电点也由8.7变为小于5.XPS分析结果显示,nZVI和nZVI/PSS表面元素构成相同,但nZVI/PSS表面有零价铁存在,而nZVI表面则主要由铁的氧化物组成.实验结果表明,两种纳米铁对Cr(VI)的去除率非常接近,在纳米铁投加量为1.0g·L-1,Cr(VI)初始浓度为100 mg·L-1的条件下,Cr(VI)的去除率在10 min内均能达到95％,在30 min内能达99％,表明nZVI/PSS具有较高活性.     

Iron Oxide Nanoparticles for Magnetically-Guided and Magnetically-Responsive Drug Delivery

In this review, we discuss the recent advances in and problems with the use of magnetically-guided and magnetically-responsive nanoparticles in drug delivery and magnetofection. In magnetically-guided nanoparticles, a constant external magnetic field is used to transport magnetic nanoparticles loaded with drugs to a specific site within the body or to increase the transfection capacity. Magnetofection is the delivery of nucleic acids under the influence of a magnetic field acting on nucleic acid vectors that are associated with magnetic nanoparticles. In magnetically-responsive nanoparticles, magnetic nanoparticles are encapsulated or embedded in a larger colloidal structure that carries a drug. In this last case, an alternating magnetic field can modify the structure of the colloid, thereby providing spatial and temporal control over drug release.