Formation Of Composite Nanoparticles Research Articles

Preparation and characterization of pH-responsive metal-polyphenol structure coated nanoparticles

In this paper, tannic acid (TA) and Fe3+ were added to form a layer of metal-polyphenol network structure on the surface of the nanoparticles which were fabricated by zein and carbon quantum dots (CQDs) encapsulating phlorotannins (PTN). pH-responsive nanoparticles were prepared successfully (zein-PTN-CQDs-FeIII). Further, the formation of composite nanoparticles was confirmed by a series of characterization methods. The zeta-potential and Fourier transform infrared spectroscopy data proved that electrostatic interaction and hydrogen bonding are dominant forces to form nanoparticles. The encapsulation efficiency (EE) revealed that metal-polyphenol network structure could improve the EE of PTN. Thermogravimetric analysis and differential scanning calorimetry experiment indicated the thermal stability of zein-PTN-CQDs-FeIII nanoparticles increased because of metal-polyphenol network structure. The pH-responsive nanoparticles greatly increased the release rate of active substances and achieved targeted release.

Experiments to Improve the Efficiency of Obtaining Brass Nanoparticles by Evaporation by a Continuous Beam of High-Energy Electrons

Composite, copper and zinc containing nanoparticles and brass nanoparticles have been obtained by a high-performance method of evaporation of substances by a relativistic electron beam. The change in the stoichiometry of nanopowders produced by stepwise irradiation of a brass ingot placed in a single-zone graphite crucible is considered. It was found that the production of such particles depends on the concentration of saturated vapors of zinc and copper. A two-zone configuration of the crucible has been developed, which makes it possible to realize the simultaneous evaporation of the constituent components, thereby providing the conditions for the formation of uniform brass nanoparticles with a uniform distribution of elements and a high yield of nanopowder. X-ray diffraction analysis (XRD), Transmission electron microscopy (TEM), Energy dispersive X-ray analysis (EDX) were carried out, and the specific surface of the obtained nanoparticles was determined. The mechanism of formation of composite nanoparticles is discussed.

Physicochemical stability, antioxidant activity, and antimicrobial activity of quercetin-loaded zein nanoparticles coated with dextrin-modified anionic polysaccharides

Core-shell biopolymer nanoparticles are assembled from a hydrophobic protein (zein) core and a hydrophilic polysaccharide (carboxymethyl dextrin) shell. The nanoparticles were shown to have good stability and the ability to protect quercetin from chemical degradation under long-term storage, pasteurization, and UV irradiation. Spectroscopy analysis shows that electrostatic, hydrogen bonding, and hydrophobic interactions are the main driving forces for the formation of composite nanoparticles. Quercetin coated with nanoparticles significantly enhanced its antioxidant and antibacterial activities and showed good stability and slow release in vitro during simulated gastrointestinal digestion. Furthermore, the encapsulation efficiency of carboxymethyl dextrin-coated zein nanoparticles (81.2%) for quercetin was significantly improved compared with that of zein nanoparticles alone (58.4%). These results indicate that carboxymethyl dextrin-coated zein nanoparticles can significantly improve the bioavailability of hydrophobic nutrient molecules such as quercetin and provide a valuable reference for their application in the field of biological delivery of energy drinks and food.

Synthesis, Characterization, Anticancer, and Antimicrobial Activities of Bimetallic Silver and Gold Nanoparticles Synthesized Using a Purple Non‐Sulfur Bacterium Rhodopseudomonas faecalis

AbstractOne of the recent and actively researched areas is the synthesis of bimetallic nanoparticles (BMNPs). Silver and gold BMNPs are prepared from aqueous AgNO3 and HAuCL4 as the precursors using the as prepared culture filtrate of Rhodopseudomonas faecalis as a reducing agent in aqueous medium. An ambient temperature of 25°C is maintained throughout the process, where the AgNO3 and HAuCL4 solution in 1:1 v/v is stirred continuously and culture filtrate is added. The synthesis of gold and silver nanoparticles is shown by the brown color which indicates the formation of composite nanoparticles. The characterization is done using different kinds of techniques. Synthesized nanoparticles size is in the range between 31.71 and 153.7 nm. Scanning electron microscopy (SEM) analysis shows that the nanoparticles are in small and round in shape. The anticancer and antimicrobial activities of the BMNPs are investigated. Anticancer activity of composite nanoparticles reveals that the composite nanoparticles show more cytotoxicity toward cancer cell lines HT‐29 and MCF‐7. The synthesized composite nanoparticles can be used as efficient antimicrobials and anticancer agents for diagnosis, treatment of various infections, and cancers.

Disulfide-containing polymer delivery of C527 and a Platinum(IV) prodrug selectively inhibited protein ubiquitination and tumor growth on cisplatin resistant and patient-derived liver cancer models.

USP1 (Ubiquitin-specific protease 1) is closely related to the prognosis of patients with liver cancer and plays an important role in DNA damage repair. C527 is a selective USP1 inhibitor (USP1i), which can regulate the protein ubiquitination to effectively inhibit the proliferation of cancer cells. However, its clinical application is hindered due to the poor water solubility and lack of tumor targeting. Moreover, the efficacy of single use of USP1i is still limited. Herein, a glutathione (GSH) sensitive amphiphilic polymer (poly (2-HD-co-HPMDA)-mPEG, PHHM) with disulfide bonds in the main chain was designed to encapsulate the USP1i as well as platinum (IV) prodrug (Pt (IV)-C12), resulting in the formation of composite nanoparticles, i.e., NP-Pt-USP1i. NP-Pt-USP1i can inhibit the DNA damage repair by targeting USP1 by the encapsulated USP1i, which ultimately increases the sensitivity of tumor cells to cisplatin and enhances the anti-cancer efficacy of cisplatin. Finally, an intraperitoneal tumor mice model and a patient-derived xenograft (PDX) of liver cancer mice model were established to prove that NP-Pt-USP1i could effectively inhibit the tumor growth. This work further validated the possibility of therapeutically target USP1 by USP1i in combination with DNA damaging alkylating agents, which could become a promising cancer treatment modality in the future.

Preparation, characterization of naringenin, β-cyclodextrin and carbon quantum dot antioxidant nanocomposites

In this work, naringenin loaded β-cyclodextrin and carbon quantum dots composite nanoparticles were successfully fabricated. The results showed that incorporation of carbon quantum dots not only enhanced antioxidant activities of nanoparticles but also improved encapsulation efficiency of naringenin. Further, the formation of composite nanoparticles was confirmed by a series of characterization methods. The zeta-potential and Fourier transform infrared spectroscopy data proved that electrostatic interaction and hydrogen bonding are dominant forces to form nanoparticles. X-Ray Diffraction experiment revealed that the material state of the formed naringenin-β-CD-CQDs nanoparticles is amorphous in opposition to the crystalline state of naringenin, β-CD and naringenin-β-CD inclusion complex. Finally, antioxidant activity analyses against DPPH, ABTS+ and Fe2+ chelating, showed an enhanced antioxidant activity of the formed composite nanoparticles compared to their constituents. These results indicated that naringenin can be effectively entrapped in β-cyclodextrin and carbon quantum dots, forming composite nanoparticles with improved antioxidant properties.

Enhancing the stability of zein/fucoidan composite nanoparticles with calcium ions for quercetin delivery

In this study, zein and fucoidan-based composite nanoparticles were prepared by the antisolvent precipitation method. The effects of different calcium ion (Ca2+, 0–3.0 mM) concentrations on the stability of the composite nanosystems loaded with quercetin were studied under different conditions (pH, temperature, salt concentration, and ultraviolet light irradiation), and the composite nanoparticles were characterized. Electrostatic interactions, hydrogen bonding, and hydrophobic interactions are the main forces underlying the formation of composite nanoparticles. The addition of Ca2+ led to improved release of the active substances from the composite nanoparticles in simulated digestive solutions (especially when the Ca2+ concentration was 1.5 mM). The composite nanosystems based on alcohol-soluble proteins and anionic polysaccharides with added Ca2+ can be potentially applied for the delivery of active substances.

Galvanic Replacement of Liquid Metal/Reduced Graphene Oxide Frameworks

AbstractGalvanic replacement reaction has been widely concerned, where a variety of materials can be nanostructured in different shapes. The galvanic replacement of gallium‐based liquid metals (LMs) can be remarkably valued, because the highly dynamic and homogeneous film of LMs can offer more active metal atoms for the reaction. Nevertheless, the galvanic replacement mechanism of the gallium‐based LM nanodroplets is still unrevealed entirely. To overcome this challenge, 2D graphene material (reduced graphene oxide, RGO) is employed to stabilize the liquid metal droplets and restrain the formation of oxide layer for the first time (LM@RGO). Two types of galvanic replacement patterns (intracellular and extracellular replacements) are revealed, which depend on the Gibbs free energy of redox reaction. The extracellular replacement pattern is adopted to produce the noble nanoparticles and the multilayered nanoparticles. In the intracellular replacement pattern, the galvanic replacement is not limited on the surface of LM@RGO. Owing to the internal alloying, LM@RGO with the superior electrochemical detection sensitivity is utilized to detect heavy metal ions. LM@RGO shows great potential in the application of preparing noble metal nanoparticles, the formation of composite nanoparticles with delicate structure and electrochemical detection of heavy metal ions.

Zein/fucoidan-based composite nanoparticles for the encapsulation of pterostilbene: Preparation, characterization, physicochemical stability, and formation mechanism

The objective of this work is to fabricate zein/fucoidan composite nanoparticles for the delivery of pterostilbene, a hydrophobic nutraceutical with diverse beneficial biological activities. Pterostilbene-encapsulated zein/fucoidan composite nanoparticles were prepared using an anti-solvent precipitation method. The fucoidan levels affected the physicochemical properties of the composite nanoparticles. When the zein to fucoidan mass ratio was 10:1, 5:1, 2:1, or 1:1, the prepared zein/fucoidan nanoparticles were stable, and these nanoparticles showed higher pterostilbene encapsulation efficiency than did zein nanoparticles. Fucoidan-stabilized zein nanoparticles exhibited globular structure with average diameters of 120–150 nm. Fourier-transform infrared spectroscopy, X-ray diffraction, and fluorescence spectrum analysis confirmed that the formation of composite nanoparticles was mainly driven by electrostatic, hydrogen-bonding, and hydrophobic interactions between pterostilbene, zein, and fucoidan. Furthermore, the photochemical stability of pterostilbene encapsulated in zein/fucoidan nanoparticles was markedly better than that of pterostilbene loaded in zein nanoparticles or unencapsulated pterostilbene. Zein/fucoidan nanoparticles provided a better controlled release of pterostilbene than did zein nanoparticles under simulated gastrointestinal conditions. Moreover, the cytotoxicity assay demonstrated that zein/fucoidan nanoparticles were nontoxic to Caco-2, HK-2, and L-02 cells. Based on our results, the zein/fucoidan nanoparticles may be a promising delivery carrier for the encapsulation, protection, and release of pterostilbene.

Composite nanoparticles: applications, creation mechanism, properties

Annotation This article presents data on the use of Janus-like and core-shell composite nanoparticles consisting of two substances—metal and semiconductor—in nanophotonics and spectroscopy. Investigations were carried out of the mechanism of formation of composite nanoparticles, based on the principle of minimum surface energy of the system and the results of molecular dynamics modelling. Integral representation was employed to analyse size distribution function of nanoparticles, and it was concluded that coagulation predominates during particle formation.

Curcumin encapsulation in zein-rhamnolipid composite nanoparticles using a pH-driven method

Zein is widely used to encapsulate non-polar bioactives due to its ability to form protein nanoparticles with hydrophobic interiors. In this study, a simple pH-driven method, which does not use organic solvents, was employed to fabricate zein-rhamnolipid composite nanoparticles. An alkaline zein solution (pH 12.0) was mixed with an acidic rhamnolipid solution (pH 2.0), which led to the spontaneous formation of composite nanoparticles (pH 7.0). The possibility of using these nanoparticles to encapsulate and deliver curcumin was then studied. Nanoparticle properties, such as size and charge, were mainly determined by the mass ratio of zein-to-rhamnolipid used. The nanoparticles formed were spherical and relatively small (d ≈ 100 nm) according to dynamic light scattering and transmission electron microscopy. Nanoparticle suspensions remained stable from pH 5 to 9 but aggregated under more acidic conditions. At neutral pH, the nanoparticles were stable at low ionic strengths (<100 mM NaCl), but aggregated at higher electrolyte levels. Moreover, they remained stable when incubated at relatively low temperatures (37 or 55 °C) but aggregated at higher temperatures (90 °C). Curcumin was loaded into the nanoparticles using the pH-shift method, which led to a high encapsulation efficiency. The nanoparticles were able to effectively protect the curcumin from degradation during one-month storage at both 25 and 37 °C. The food-grade nanoparticles fabricated in this study may be suitable as delivery systems for hydrophobic nutraceuticals in functional foods and beverages.

Special aspects of the thermodynamics of formation and polarisation of Ag/Si nanoparticles

An analysis of the mechanism of formation of composite nanoparticles of Ag/Si shows that it depends on their stoichiometric composition, conditions of condensation and crystallisation. During the crystallisation of the nanoparticle core, eutectics consisting of silver and silicon layers are formed. Diffraction fringes in the nanoparticle core are caused by the formation of eutectic platelets during crystallisation of phase components. Layers of the conductor Ag and semiconductor Si form, creating an electric charge at the boundaries. We demonstrate the dependence of the sizes of these Ag/Si nanoparticles on the rates of heating and cooling of the materials during synthesis.

Highly hydrophilic and antifouling nanofiltration membrane incorporated with water-dispersible composite activated carbon/chitosan nanoparticles

Novel composite activated carbon/chitosan nanoparticles (ACh) were synthesized by dipping and incorporated into poly(ether)sulfone (PES) based nanofiltration membranes, to investigate their effect on the membrane properties and performance. The hydrophobic activated carbon nanoparticles were functionalized with hydrophilic chitosan to increase their dispersibility and hydrophilicity. The FTIR and SEM analysis confirm the formation of composite nanoparticles decisively. UV–vis spectra of activated carbon before and after modification with chitosan confirmed a better dispersion of composite nanoparticles. An improvement of hydrophilicity and porosity were obtained by increasing the concentration of composite nanoparticles up to 0.5wt%. The water flux was also increased from 21 to 30 (L/m2h) by utilizing composite nanoparticles up to 0.5wt%. The mean pore size was decreased for all concentrations of composite nanoparticles, due to their great dispersion. The membrane roughness was declined from 19.2nm (average roughness) for PES to 5.9nm for a membrane including 0.5wt% nanoparticles. The surface SEM image of a membrane containing 0.5wt% nanoparticles confirmed the reduction of pore size after addition of nanoparticles to the casting solution. The results showed a sharp increase of salt rejection in all concentrations of ACh; the highest value was 97% for 1wt%. The membrane with 0.5wt% nanoparticles was found having optimal properties; its performance was tested by analyzing the antifouling performance. The flux recovery was found twice higher than that of a corresponding PES membrane.

Structure, physicochemical stability and in vitro simulated gastrointestinal digestion properties of β-carotene loaded zein-propylene glycol alginate composite nanoparticles fabricated by emulsification-evaporation method

In this study, zein-propylene glycol alginate (PGA) composite nanoparticles were fabricated by emulsification-evaporation method, and their potential to be a delivery vehicle for β-carotene was investigated. The results showed that different PGA levels resulted in various structural characteristics, physicochemical stability and properties of in vitro simulated gastrointestinal digestion of β-carotene loaded zein-PGA composite nanoparticles. The analyses of fluorescence spectrum, circular dichroism and fourier transform infrared spectroscopy revealed that electrostatic interaction, hydrogen bonding and hydrophobic attraction played important roles in the formation of composite nanoparticles. The β-carotene entrapped in nanoparticles was amorphous, confirmed by differential scanning calorimetry. The improved physicochemical stability and the sustained release of β-carotene in nanoparticles proved the potential of zein-PGA composite nanoparticles as an excellent vehicle to deliver β-carotene in food system.

Synthesis of [Fe(Leq)(Lax)] n coordination polymer nanoparticles using blockcopolymer micelles.

Spin-crossover compounds are a class of materials that can change their spin state from high spin (HS) to low spin (LS) by external stimuli such as light, pressure or temperature. Applications demand compounds with defined properties concerning the size and switchability that are maintained when the compound is integrated into composite materials. Here, we report the synthesis of [Fe(Leq)(Lax)]n coordination polymer (CP) nanoparticles using self-assembled polystyrene-block-poly(4-vinylpyridine) (PS-b-P4VP) block copolymer (BCP) micelles as template. Variation of the solvent (THF and toluene) and the rigidity of the axial ligand Lax (Lax = 1,2-di(pyridin-4-yl)ethane) (bpea), trans-1,2-di(pyridin-4-yl)ethene (bpee), and 1,2-di(pyridin-4-yl)ethyne) (bpey); Leq = 1,2-phenylenebis(iminomethylidyne)-bis(2,4-pentanedionato)(2−)) allowed the determination of the preconditions for the selective formation of nanoparticles. A low solubility of the CP in the used solvent and a high stability of the Fe–L bond with regard to ligand exchange are necessary for the formation of composite nanoparticles where the BCP micelle is filled with the CP, as in the case of the [FeLeq(bpey)]n@BCP. Otherwise, in the case of more flexible ligands or ligands that lead to high spin complexes, the formation of microcrystals next to the CP–BCP nanoparticles is observed above a certain concentration of [Fe(Leq)(Lax)]n. The core of the nanoparticles is about 45 nm in diameter due to the templating effect of the BCP micelle, independent of the used iron complex and [Fe(Leq)(Lax)]n concentration. The spin-crossover properties of the composite material are similar to those of the bulk for FeLeq(bpea)]n@BCP while pronounced differences are observed in the case of [FeLeq(bpey)]n@BCP nanoparticles.

Hydrogenation of the nanopowders that form in a carbon-helium plasma stream during the introduction of Ni and Mg

Composite nanoparticles consisting of magnesium, nickel, and carbon atoms are studied both theoretically and experimentally. The calculations performed in terms of the density functional theory show that the jump frequency of hydrogen atoms in nickel-containing magnesium hydride increases substantially near impurity nickel atoms; as a result, the rate of hydrogen absorption by magnesium also increases. Nickel on the magnesium surface is shown to be absorbed via an island growth mechanism. Composite Mg-C, Ni-C, and Mg-Ni-C powders are produced by plasmachemical synthesis in a carbon-helium plasma stream. Hydrogen is introduced into a chamber during synthesis. It is found by X-ray photoelectron spectroscopy and thermogravimetric analysis that, among these three composites, only Mg-Ni-C contains magnesium fixed in the MgH2 compound. The process of such “ultrarapid” hydrogenation of magnesium, which occurs in the time of formation of composite nanoparticles, can be explained by the catalytic action of nickel, which is enhanced by a high temperature. Scanning electron microscopy micrographs demonstrate the dynamics of the dehydrogenation of Mg-Ni-C composite nanoparticles in heating by an electron beam.

Anatase-Type Ti&lt;sub&gt;1-2x&lt;/sub&gt;Nb&lt;sub&gt;x&lt;/sub&gt;Al&lt;sub&gt;x&lt;/sub&gt;O&lt;sub&gt;2&lt;/sub&gt; Solid Solution/Silica (SiO&lt;sub&gt;2&lt;/sub&gt;) Composite Nanoparticles: Synthesis, Phase Stability, and Photocatalytic Performance

Composite nanoparticles (anatase-type Ti1-2XNbXAlXO2 solid solution/SiO2) were directly synthesized from precursor solutions in the presence of urea under mild hydrothermal conditions at 180 °C for 5 h. The crystallite size of anatase was gradually decreased with increased silica content in the composite nanoparticles formed under weakly basic hydrothermal conditions via the hydrolysis of urea. The composite nanoparticles with composition Ti0.9Nb0.05Al0.05O2/SiO2 = 100/10 mol% showed good photocatalytic activity. The anatase-to-rutile phase transformation in the course of heating in air was retarded to maintain the anatase-type structure up to more than 1050 °C without a trace of rutile phase by the formation of composite nanoparticles (Ti0.90Nb0.05Al0.05O2/SiO2 = 100/20 mol%) with amorphous silica.

Palladium infiltration in high surface area microporous silica nanoparticles

Metallic Pd clusters were embedded into a host matrix of microporous SiO 2 nanoparticles via a solution reduction of Pd(NO 3) 2 by hydrazine hydrate. The infiltration of 33 wt.% Pd leads to a 13% porosity loss of SiO 2 nanoparticles, which demonstrated an initial surface area of 748 m 2/g. The presence of Pd in the pores was demonstrated by EDS spectroscopy and by X-ray diffraction. The metallic guest species presumably reside in the accessible micropores with an estimated size about 1.3 nm. Hydrogen uptake was measured for Pd-infiltrated SiO 2 nanoparticles. A possible mechanism for the formation of composite nanoparticles is proposed based on electrostatic interaction between Pd 2+ and SiO 2 nanoparticles.