Editorial

3 pages, 184 KiB

Open AccessEditorial

Editorial for the Special Issue on “Process Intensification Techniques for the Production of Nanoparticles”

by Giorgio Vilardi and Marco Stoller

Nanomaterials 2021, 11(6), 1534; https://doi.org/10.3390/nano11061534 - 10 Jun 2021

Viewed by 1668

According to ISO/TS 80004, a nanomaterial is defined as the “material with any external dimension in the nanoscale or having internal structure or surface structure in the nanoscale”, with nanoscale defined as the “length range approximately from 1 nm to 100 nm” [...] [...] Read more.

According to ISO/TS 80004, a nanomaterial is defined as the “material with any external dimension in the nanoscale or having internal structure or surface structure in the nanoscale”, with nanoscale defined as the “length range approximately from 1 nm to 100 nm” [...] Full article

(This article belongs to the Special Issue Process Intensification Techniques for the Production of Nanoparticles)

Research

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13 pages, 1741 KiB

Open AccessArticle

Time Optimization of Seed-Mediated Gold Nanotriangle Synthesis Based on Kinetic Studies

by Ekaterina Podlesnaia, Andrea Csáki and Wolfgang Fritzsche

Nanomaterials 2021, 11(4), 1049; https://doi.org/10.3390/nano11041049 - 20 Apr 2021

Cited by 8 | Viewed by 2748

Abstract

The synthesis of shape-anisotropic plasmonic nanoparticles such as gold nanotriangles is of increasing interest. These particles have a high potential for applications due to their notable optical properties. A key challenge of the synthesis is usually the low reproducibility. Even the optimized seed-based [...] Read more.

The synthesis of shape-anisotropic plasmonic nanoparticles such as gold nanotriangles is of increasing interest. These particles have a high potential for applications due to their notable optical properties. A key challenge of the synthesis is usually the low reproducibility. Even the optimized seed-based methods often lack in the synthesis yield or are labor- and time-consuming. In this work, a seed-mediated synthesis with high reproducibility is replicated in order to determine the necessary reaction time for each step. Online monitoring of the reaction mixtures by UV–VIS spectroscopy is used as a powerful tool to track the evolution of the synthesis. The kinetics of the individual stages is elucidated by real-time investigations. As a consequence, the complete synthesis could be optimized and can now be realized in a single day instead of three without any loss in the resulting sample quality. Full article

(This article belongs to the Special Issue Process Intensification Techniques for the Production of Nanoparticles)

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9 pages, 4191 KiB

Open AccessArticle

Enhanced Electrochemical Performance of LiFePO₄ Originating from the Synergistic Effect of ZnO and C Co-Modification

by Xiaohua Chen, Yong Li and Juan Wang

Nanomaterials 2021, 11(1), 12; https://doi.org/10.3390/nano11010012 - 23 Dec 2020

Cited by 19 | Viewed by 2111

Abstract

Olivine-structure LiFePO₄ is considered as promising cathode materials for lithium-ion batteries. However, the material always sustains poor electron conductivity, severely hindering its further commercial application. In this work, zinc oxide and carbon co-modified LiFePO₄ nanomaterials (LFP/C-ZnO) were prepared by an inorganic-based [...] Read more.

Olivine-structure LiFePO₄ is considered as promising cathode materials for lithium-ion batteries. However, the material always sustains poor electron conductivity, severely hindering its further commercial application. In this work, zinc oxide and carbon co-modified LiFePO₄ nanomaterials (LFP/C-ZnO) were prepared by an inorganic-based hydrothermal route, which vastly boosts its performance. The sample of LFP/C-xZnO (x = 3 wt%) exhibited well-dispersed spherical particles and remarkable cycling stability (initial discharge capacities of 138.7 mAh/g at 0.1 C, maintained 94.8% of the initial capacity after 50 cycles at 0.1 C). In addition, the cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) disclose the reduced charge transfer resistance from 296 to 102 Ω. These suggest that zinc oxide and carbon modification could effectively minimize charge transfer resistance, improve contact area, and buffer the diffusion barrier, including electron conductivity and the electrochemical property. Our study provides a simple and efficient strategy to design and optimize promising olivine-structural cathodes for lithium-ion batteries. Full article

(This article belongs to the Special Issue Process Intensification Techniques for the Production of Nanoparticles)

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16 pages, 2633 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Empirical Modelling of Hydrodynamic Effects on Starch Nanoparticles Precipitation in a Spinning Disc Reactor

by Sahr Sana, Vladimir Zivkovic and Kamelia Boodhoo

Nanomaterials 2020, 10(11), 2202; https://doi.org/10.3390/nano10112202 - 04 Nov 2020

Cited by 6 | Viewed by 2964

Abstract

Empirical correlations have been developed to relate experimentally determined starch nanoparticle size obtained in a solvent–antisolvent precipitation process with key hydrodynamic parameters of a spinning disc reactor (SDR). Three different combinations of dimensionless groups including a conventional Reynolds number (Re), rotational [...] Read more.

Empirical correlations have been developed to relate experimentally determined starch nanoparticle size obtained in a solvent–antisolvent precipitation process with key hydrodynamic parameters of a spinning disc reactor (SDR). Three different combinations of dimensionless groups including a conventional Reynolds number (Re), rotational Reynolds number (Re_ω) and Rossby number (Ro) have been applied in individual models for two disc surfaces (smooth and grooved) to represent operating variables affecting film flow such as liquid flowrate and disc rotational speed, whilst initial supersaturation (S) has been included to represent varying antisolvent concentrations. Model 1 featuring a combination of Re, Re_ω and S shows good agreement with the experimental data for both the grooved and smooth discs. For the grooved disc, Re has a greater impact on particle size, whereas Re_ω is more influential on the smooth disc surface, the difference likely being due to the passive mixing induced by the grooves irrespective of the magnitude of the disc speed. Supersaturation has little impact on particle size within the limited initial supersaturation range studied. Model 2 which characterises both flow rate and disc rotational speed through Ro alone and combined with Re was less accurate in predicting particle size due to several inherent limitations. Full article

(This article belongs to the Special Issue Process Intensification Techniques for the Production of Nanoparticles)

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12 pages, 4679 KiB

Open AccessArticle

Sono-Assembly of the [Arg-Phe]₄ Octapeptide into Biofunctional Nanoparticles

by Anshul Baral, Sukhvir K. Bhangu, Rita Cimino, Juliane N. B. D. Pelin, Wendel A. Alves, Santanu Chattopadhyay, Muthupandian Ashokkumar and Francesca Cavalieri

Nanomaterials 2020, 10(9), 1772; https://doi.org/10.3390/nano10091772 - 08 Sep 2020

Cited by 6 | Viewed by 2225

Abstract

High-frequency ultrasound treatment is found to be a one-pot green technique to produce peptide-based nanostructures by ultrasound assisted self-assembly of oligopeptides. [Arg-Phe]₄ octapeptides, consisting of alternating arginine (Arg/R) and phenylalanine (Phe/F) sequences, were subjected to 430 kHz ultrasound in aqueous solution in [...] Read more.

High-frequency ultrasound treatment is found to be a one-pot green technique to produce peptide-based nanostructures by ultrasound assisted self-assembly of oligopeptides. [Arg-Phe]₄ octapeptides, consisting of alternating arginine (Arg/R) and phenylalanine (Phe/F) sequences, were subjected to 430 kHz ultrasound in aqueous solution in the absence of any external agents, to form [RF]₄ nanoparticles ([RF]₄-NPs), ~220 nm in diameter. A comprehensive analysis of the obtained nanoparticles demonstrated that the aromatic moieties of the oligopeptides can undergo oxidative coupling to form multiple oligomeric species, which then self-assemble into well-defined fluorescent nanoparticles. [RF]₄-NPs were functionalized with polyethylene glycol (PEGylated) to improve their colloidal stability. Unlike the parent peptide, the PEGylated [RF]₄-NPs showed limited cytotoxicity towards MDA-MB-231 cells. Furthermore, the intracellular trafficking of PEGylated [RF]₄-NPs was investigated after incubation with MDA-MB-231 cells to demonstrate their efficient endo-lysosomal escape. This work highlights that the combined use of ultrasonic technologies and peptides enables easy fabrication of nanoparticles, with potential application in drug delivery. Full article

(This article belongs to the Special Issue Process Intensification Techniques for the Production of Nanoparticles)

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16 pages, 3743 KiB

Open AccessArticle

PEI-Mediated Transient Transfection of High Five Cells at Bioreactor Scale for HIV-1 VLP Production

by Eduard Puente-Massaguer, Florian Strobl, Reingard Grabherr, Gerald Striedner, Martí Lecina and Francesc Gòdia

Nanomaterials 2020, 10(8), 1580; https://doi.org/10.3390/nano10081580 - 12 Aug 2020

Cited by 12 | Viewed by 4977

Abstract

High Five cells are an excellent host for the production of virus-like particles (VLPs) with the baculovirus expression vector system (BEVS). However, the concurrent production of high titers of baculovirus hinder the purification of these nanoparticles due to similarities in their physicochemical properties. [...] Read more.

High Five cells are an excellent host for the production of virus-like particles (VLPs) with the baculovirus expression vector system (BEVS). However, the concurrent production of high titers of baculovirus hinder the purification of these nanoparticles due to similarities in their physicochemical properties. In this study, first a transient gene expression (TGE) method based on the transfection reagent polyethylenimine (PEI) is optimized for the production of HIV-1 VLPs at shake flask level. Furthermore, VLP production by TGE in High Five cells is successfully demonstrated at bioreactor scale, resulting in a higher maximum viable cell concentration (5.1 × 10⁶ cell/mL), the same transfection efficiency and a 1.8-fold increase in Gag-eGFP VLP production compared to shake flasks. Metabolism analysis of High Five cells indicates a reduction in the consumption of the main metabolites with respect to non-transfected cell cultures, and an increase in the uptake rate of several amino acids when asparagine is depleted. Quality assessment by nanoparticle tracking analysis and flow virometry of the VLPs produced shows an average size of 100–200 nm, in agreement with immature HIV-1 viruses reported in the literature. Overall, this work demonstrates that the High Five/TGE system is a suitable approach for the production of VLP-based vaccine candidates and other recombinant proteins. Full article

(This article belongs to the Special Issue Process Intensification Techniques for the Production of Nanoparticles)

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15 pages, 3478 KiB

Open AccessArticle

ZnO Nano-Particles Production Intensification by Means of a Spinning Disk Reactor

by Marco Stoller and Javier Miguel Ochando-Pulido

Nanomaterials 2020, 10(7), 1321; https://doi.org/10.3390/nano10071321 - 05 Jul 2020

Cited by 20 | Viewed by 2785

Abstract

Zinc Oxide is widely used in many industrial sectors, ranging from photocatalysis, rubber, ceramic, medicine, and pigment, to food and cream additive. The global market is estimated to be USD 3600M yearly, with a global production of 10 Mt. In novel applications, size [...] Read more.

Zinc Oxide is widely used in many industrial sectors, ranging from photocatalysis, rubber, ceramic, medicine, and pigment, to food and cream additive. The global market is estimated to be USD 3600M yearly, with a global production of 10 Mt. In novel applications, size and shape may sensibly increase the efficiency and a new nano-ZnO market is taking the lead (USD 2000M yearly with a capacity of 1 Mt and an expected Compound Annual Growth Rate of 20%/year). The aim of this work was to investigate the possibility of producing zinc oxide nanoparticles by means of a spinning disk reactor (SDR). A lab-scale spinning disk reactor, previously used to produce other nanomaterials such as hydroxyapatite or titania, has been investigated with the aim of producing needle-shaped zinc oxide nanoparticles. At nanoscale and with this shape, the zinc oxide particles exhibit their greatest photoactivity and active area, both increasing the efficiency of photocatalysis and ultraviolet (UV) absorbance. Working at different operating conditions, such as at different disk rotational velocity, inlet distance from the disk center, initial concentration of Zn precursor and base solution, and inlet reagent solution flowrate, in certain conditions, a unimodal size distribution and an average dimension of approximately 56 nm was obtained. The spinning disk reactor permits a continuous production of nanoparticles with a capacity of 57 kg/d, adopting an initial Zn-precursor concentration of 0.5 M and a total inlet flowrate of 1 L/min. Product size appears to be controllable, and a lower average dimension (47 nm), adopting an initial Zn-precursor concentration of 0.02 M and a total inlet flow-rate of 0.1 L/min, can be obtained, scarifying productivity (0.23 kg/d). Ultimately, the spinning disk reactor qualifies as a process-intensified equipment for targeted zinc oxide nanoparticle production in shape in size. Full article

(This article belongs to the Special Issue Process Intensification Techniques for the Production of Nanoparticles)

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15 pages, 4192 KiB

Open AccessArticle

Green-Synthesization of Silver Nanoparticles Using Endophytic Bacteria Isolated from Garlic and Its Antifungal Activity against Wheat Fusarium Head Blight Pathogen Fusarium graminearum

by Ezzeldin Ibrahim, Muchen Zhang, Yang Zhang, Afsana Hossain, Wen Qiu, Yun Chen, Yanli Wang, Wenge Wu, Guochang Sun and Bin Li

Nanomaterials 2020, 10(2), 219; https://doi.org/10.3390/nano10020219 - 27 Jan 2020

Cited by 125 | Viewed by 5884

Abstract

Nanoparticles are expected to play a vital role in the management of future plant diseases, and they are expected to provide an environmentally friendly alternative to traditional synthetic fungicides. In the present study, silver nanoparticles (AgNPs) were green synthesized through the mediation by [...] Read more.

Nanoparticles are expected to play a vital role in the management of future plant diseases, and they are expected to provide an environmentally friendly alternative to traditional synthetic fungicides. In the present study, silver nanoparticles (AgNPs) were green synthesized through the mediation by using the endophytic bacterium Pseudomonas poae strain CO, which was isolated from garlic plants (Allium sativum). Following a confirmation analysis that used UV–Vis, we examined the in vitro antifungal activity of the biosynthesized AgNPs with the size of 19.8–44.9 nm, which showed strong inhibition in the mycelium growth, spore germination, the length of the germ tubes, and the mycotoxin production of the wheat Fusarium head blight pathogen Fusarium graminearum. Furthermore, the microscopic examination showed that the morphological of mycelia had deformities and collapsed when treated with AgNPs, causing DNA and proteins to leak outside cells. The biosynthesized AgNPs with strong antifungal activity were further characterized based on analyses of X-ray diffraction, transmission electron microscopy, scanning electron microscopy, EDS profiles, and Fourier transform infrared spectroscopy. Overall, the results from this study clearly indicate that the biosynthesized AgNPs may have a great potential in protecting wheat from fungal infection. Full article

(This article belongs to the Special Issue Process Intensification Techniques for the Production of Nanoparticles)

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Review

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21 pages, 4996 KiB

Open AccessFeature PaperReview

Process Intensification Approach Using Microreactors for Synthesizing Nanomaterials—A Critical Review

by Vikas Hakke, Shirish Sonawane, Sambandam Anandan, Shriram Sonawane and Muthupandian Ashokkumar

Nanomaterials 2021, 11(1), 98; https://doi.org/10.3390/nano11010098 - 04 Jan 2021

Cited by 55 | Viewed by 4952

Abstract

Nanomaterials have found many applications due to their unique properties such as high surface-to-volume ratio, density, strength, and many more. This review focuses on the recent developments on the synthesis of nanomaterials using process intensification. The review covers the designing of microreactors, design [...] Read more.

Nanomaterials have found many applications due to their unique properties such as high surface-to-volume ratio, density, strength, and many more. This review focuses on the recent developments on the synthesis of nanomaterials using process intensification. The review covers the designing of microreactors, design principles, and fundamental mechanisms involved in process intensification using microreactors for synthesizing nanomaterials. The microfluidics technology operates in continuous mode as well as the segmented flow of gas–liquid combinations. Various examples from the literature are discussed in detail highlighting the advantages and disadvantages of microfluidics technology for nanomaterial synthesis. Full article

(This article belongs to the Special Issue Process Intensification Techniques for the Production of Nanoparticles)

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