Control Of Particle Size Research Articles

Thermoresponsiveness Across the Physiologically Accessible Range: Effect of Surfactant, Cross-Linker, and Initiator Content on Size, Structure, and Transition Temperature of Poly(N-isopropylmethacrylamide) Microgels.

The influence of surfactant, cross-linker, and initiator on the final structure and thermoresponse of poly(N-isopropylmethacrylamide) (pNIPMAM) microgels was evaluated. The goals were to control particle size (into the nanorange) and transition temperature (across the physiologically accessible range). The concentration of the reactants used in the synthesis was varied, except for the monomer, which was kept constant. The thermoresponsive suspensions formed were characterized by dynamic light scattering, small-angle X-ray scattering, atomic force microscopy, and rheology. Increasing surfactant, sodium dodecyl sulfate content, produced smaller microgels, as expected, into the nanorange and with greater internal entanglement, but with no change in phase transition temperature (LCST), which is contrary to previous reports. Increasing cross-linker, N,N-methylenebis acrylamide, content had no impact on particle size but reduced particle deformability and, again contrary to previous reports of decreases, progressively increased the LCST from 39 to 46 °C. The unusual LCST trends were confirmed using different rheological techniques. Initiator, potassium persulfate, content was found to weakly influence the outcomes. An optimized content was identified that provides functional nanogels in the 100 nm (swollen) size range with controlled LCST, just above physiological temperature. The study contributes chemistry-derived design rules for thermally responsive colloidal particles with physiologically accessible LCST for a variety of biomedical and soft robotics applications.

Comprehensive Effort on Electrode Slurry for Proton Exchange Membrane Water Electrolysis

Green hydrogen production through renewable energy-based water electrolysis is the most efficient technology for decarbonization, and demand has recently been rapidly increasing. Addressing this surge in demand requires the rapid development of reliable large-scale manufacturing methods for PEMWE membrane-electrode assemblies (MEAs).For reliable large-scale manufacturing, it is necessary to optimize electrode components, including catalysts, binders, solvents, and additives, as well as their dispersion methods. Particularly, ensuring the homogeneity and stability of the electrode slurry is crucial.In this study, we enhanced the stability of the electrode slurry to twice and five times that of the existing standard by selecting an appropriate dispersion method for the metal-oxide oxygen evolution reaction (OER) catalyst and by adjusting the OER catalyst (both support and particle size control), respectively. Additionally, we secured stable electrode coating characteristics by controlling the solvent composition and additives, based on the rheology of the slurry. By optimizing the composition, formulation, and preparation method of the electrode slurry to form an optimal catalyst layer, we achieved a 20% improvement in performance compared to commercial MEA products.

Nanoengineering Multilength-Scale Porous Hierarchy in Mesoporous Metal-Organic Framework Single Crystals.

Developing a reliable method for constructing mesoporous metal-organic frameworks (MOFs) with single-crystalline forms remains a challenging task despite numerous efforts. This study presents a solvent-mediated assembly method for fabricating zeolitic imidazolate framework (ZIF) single-crystal nanoparticles with a well-defined micro-mesoporous structure using polystyrene-block-poly(ethylene oxide) diblock copolymer micelles as a soft-template. The precise control of particle sizes, ranging from 85 to 1200 nm, is achieved by regulating nucleation and crystal growth rates while maintaining consistent pore diameters in mesoporous nanoparticles and a rhombohedral dodecahedron morphology. Furthermore, this study presents a robust platform for nanoarchitecturing to prepare hierarchically porous materials (e.g., core-shell and hollow structures), including microporous ZIF@mesoporous ZIF, hollow mesoporous ZIF, and mesoporous ZIF@mesoporous ZIF. Such a multimodal pore design, ranging from microporous to microporous/mesoporous and further micro-/meso-/macroporous, provides significant evidence for the future possibility of the structural design of MOFs.

Design of Modular, 3D‐Printed Millifluidic Mixers to Enable Sequential NanoPrecipitation (SNaP) for the Tunable Synthesis of Drug‐Loaded Nanoparticles and Microparticles

AbstractSequential NanoPrecipitation (SNaP) is a nascent controlled precipitation process for the tunable formation of polymeric particles for drug delivery and bioimaging. While SNaP utilizes the same self‐assembly principles as one‐step Flash NanoPrecipitation, SNaP is a two‐step assembly process in which the particle core formation is initiated during a first mixing step followed by particle stabilization in a second mixing step. Current SNaP experimental set‐ups use commercial millifluidic mixers connected in series, which have several limitations, including the inability to access short inter‐mixer delay times (Td). A robust, 3D‐printed, modular mixer design that enables access to short Td's (〈 25 ms) not previously accessible is reported. For the first time, it is demonstrated that decoupling the assembly steps improves control over particle size, expanding the attainable size range to include both nanoparticles and microparticles. It is empirically proven that inter‐mixer Td is a key parameter for particle size control and that particle size scales with Td in agreement with Smoluchowski's model of diffusion‐limited growth. The formation of particles ranging in size from 160 nm to 1.2 µm is shown. Finally, the applicability of the new mixers is established by encapsulating fluorophores and therapeutics into particles for the first time via SNaP.

Development of an Impinging Jet Microreactor Synthesis Process for Surfactant‐free Pt‐Nanoparticles as PEMFC Catalyst Component

Colloidal, surfactant‐free platinum nanoparticles were prepared via a self‐built continuous impinging jet microreactor synthesis process in alkaline aqueous methanol solution (Co4CatTM process). In these syntheses, methanol functions as a reducing agent as well as an additional solvent. Especially the synthesis of surfactant‐free nanoparticles remained challenging, and additionally, the transfer of this synthesis into a continuous process required several optimization steps. In this contribution we present highly controllable final particle sizes by adjusting process temperature, platinum precursor concentration and molar ratio of the hydroxide and platinum precursor used. The size objective of the surfactant‐free Pt nanoparticles was a range of 1 – 10 nm, due to the intended application in various catalytic processes, especially as PEMFC electrocatalyst. Dynamic light scattering (DLS), ζ‐potential measurements, transmission electron microscopy (TEM) and UV/Vis spectroscopy were used to monitor the particle stability over a certain period of time and study the rate of the reduction reaction in more detail.

Nb Doping Reduces the Primary Particle Size of the Li-Rich Cathode

Lithium-rich materials exhibit promising potential as commercial lithium-ion battery cathodes, offering a specific energy of 900 Wh.kg−1, surpassing other commercial cathode materials by more than 20%. However, challenges such as low initial efficiency, poor conductivity, and subpar cycling performance, along with rapid voltage decay, have impeded their commercialization. In this study, we propose a niobium-doping technique for lithium-rich materials. By controlling particle size during high-temperature sintering, niobium facilitates the production of highly crystalline, small-grain lithium-rich materials. This approach achieves both high capacity and long cycle life. Specifically, at 0.5 C, the pouch cell demonstrates a maximum specific capacity of 230.2 mAh.g−1, retaining 85.2% after 500 cycles, with a voltage drop of less than 0.3 mV/cycle. Additionally, we investigated the mechanism of niobium in suppressing particle growth through doping with elements of varying M-O bond strengths, obtaining systematic data.

Temperature-Sensitive Template for Preparation of ZnO/CeO2 Composite Photocatalytic Materials and Its Catalytic Performance.

In this work, a series of thermosensitive ionic liquid functionalized polymers, PNx(IL)y, with controllable morphology and particle size were prepared by free radical polymerization. Then, using the polymer PN64(IL)8 with uniform morphology as a templating agent, the ZnO composite photocatalytic materials doped with rare earth metal Ce were prepared in combination with a microwave-assisted and templated hydrothermal reaction method. Series different Ce-doping amount photocatalytic materials ZnO-Ce-x‱ were characterized by XRD, SEM, TEM, XPS, and other methods. The results demonstrated that the templated materials PN64(IL)8 can prepare ZnO-Ce-2‱ with uniform petaloid ambulacra shape, good distribution of elements, and excellent photocatalytic performance. Photocatalytic degradation experiments of methyl orange (MO) showed that when the Ce-doping amount is only 2‱, the degradation rate of organic dyes can reach 96.5% by reacting the photocatalytic materials in water for 1 h. In addition, this kind of photocatalyst can be used for the degradation of high-concentration MO, as well as being easily recovered and effectively reused by simple filtration. Therefore, the structure of this kind of photocatalyst is controllable in the preparation process with an extremely low Ce-doping amount compared with current reports, and it has a good application prospect in the field of wastewater treatment technology.

Tailoring particle size/morphology for the stable cathode performance of polygonal-shaped Li(Ni,Mn)2O4 single crystals

We regulate the particle size and crystallographic facet of single-crystal (SC) Li(Ni,Mn)2O4 (LNMO) cathode materials via flux-selective molten salt method. By simply adjusting Li2MoO4 or LiI as sintering aids, we synthesized size controlled SC particles, both small and large, and comparatively investigated their electrochemical behavior focusing on the lithiation/delithiation reactivity in conjunction with the particle size and surface planes. Considering the growth mechanism of a SC particles with a specific crystal plane, such particle size control is not determined solely by the synthetic condition but must also consider the interfacial energy of the crystal planes in conjunction with the fluxes what we used. While the initial charge capacity is similar, the given cathode using a small SC LNMO (using LiI) with uniform particle sizes (≤5 μm) exhibits outstanding rate capability with stable capacity retention under changing current density, which indicates stable lithium transport during the repetitive electrochemical reactions. The dependency of the impedance response with change in the electrode resistances as well as the stability during the cycle reactions in conjunction with the post-mortem Li distribution by using laser-induced breakdown spectroscopy as a function of porosity change and cell degradation are thoroughly discussed from the standpoint of regulated particle property.

Cellulose acetate sheet supported gold nanoparticles for the catalytic reduction of toxic organic pollutants

Abstract Water contamination by toxic organic dyes represents a significant global challenge necessitating effective remediation strategies. Due to their high catalytic activity, considerable attention has been gained to metal-based nanocatalysts. Cellulose acetate sheets supported by gold nanoparticles through a reduction method were synthesized. The composite synthesized material presents a compelling platform for catalytic reduction in the remediation of toxic organic pollutants, ensuring controlled particle size and stability. In this study, the prepared cellulose acetate sheet (CAsheet) was dipped in a 0.001 M aqueous chloroauric acid (HAuCl4) solution and reduced by immersion in a 0.1 M sodium borohydride (NaBH4) aqueous solution. After the successful preparation of virgin cellulose acetate sheet (CAsheet) and gold-supported cellulose acetate sheet (Au-CAsheet) samples were assessed by scanning electron microscopy (SEM), X-ray crystallography (XRD), energy dispersive X-rays spectroscopy (EDX), and Fourier transform infrared spectroscopy (FTIR) analysis. The catalytic reduction reaction of toxic compounds i.e. reduction of 4-nitroaniline (4-NA), Congo red (CR), and reactive yellow (RY-42) by using NaBH4. The catalytic activity of the Au-CAsheet was exhibited by the reaction rate constant (k app) values 0.3189, 0.1596, and 0.1593 min−1 for CR, 4-NA, and RY-42 respectively. This kind of procedure for Au-CAsheet synthesis may be valid for different applications in catalysis, sensing, and environmental application.

In-situ wet milling for particle size control in continuous crystallization: Expanding the attainable region

Continuous mixed-suspension mixed-product removal crystallizer cascades are robust and proven options for continuous manufacturing. However, when applied to a late-stage drug substance the desired particle size could not be achieved due to rapid crystal growth and slow secondary nucleation kinetics. This necessitated a batch terminal milling operation to achieve particle size control (Johnson et al., 2021). To overcome this and to intensify the process, an in-situ high-shear wet mill was integrated into the continuous equipment train to achieve the target physical properties of the drug substance that met the quality and manufacturability criteria needed for the drug product. This article describes the workflow used to optimize the equipment set and operational parameters. Incorporation of a high-shear wet mill operated intermittently in the continuous drug substance process greatly expanded the attainable particle size region, improved product quality, reduced cycle time, and simplified process development and scale-up compared to the process of batch milling after continuous crystallization. Small scale batch milling experiments were used to characterize milling performance at lab and production scales and inform operational space. Several lab-scale continuous runs were then used to define the process operating space and validate the process parameters necessary to meet the particle specifications of the product. Scale-up of the equipment set for in-situ milling was also demonstrated. This approach was tested at lab-scale on representative material operating for 70 h while changing the particle size of the product in real time. This illustrated the potential of intermittent milling for model-free particle size control.

A versatile method for facile and reliable synthesis of colloidal particles with a size and composition gradient

Abstract Colloidal particles play a pivotal role in numerous applications across various disciplines, many of which necessitate precise control over particle size and size distribution. Seeded growth reactions have been established as effective methods for reproducibly accessing tailor-made particles. However, conventional batch-wise syntheses only yield discrete particle sizes. With the increasing focus on complex structures in current research, there is a demand for innovative and adaptable techniques to produce colloidal particles with precise sizes and size distributions. The Controlled Emulsion Extraction Process (CrEEP) is capable of addressing this challenge. Here, we present in detail how this synthesis works and demonstrate its reliability and versatility. Our approach exploits the time-dependent particle growth and enables accessing dispersions of controlled particle size distributions. We highlight these possibilities through a variation of the monomer feed and feed composition, resulting in gradual changes in both size and glass transition temperature, respectively. Beyond its application to polymer particles, CrEEP can be seamlessly extended to other seeded-growth mechanisms, such as the silica Stöber synthesis. Consequently, the Controlled Extraction Stöber Process (CrESP) similarly yields a size gradient, showcasing the generality of this synthetic advancement. Graphical abstract

CMC-Ca(OH)2-TiO2 Nanocomposite for Paper Relics Multifunctional Restoration: Strengthening, Deacidification, UV Effect Resistance, and Antimicrobial Protection

In recent years, the demand for the protection and restoration of cultural heritage has become increasingly urgent. Particularly for paper-based cultural relics such as ancient books and paintings, their restoration is especially important due to their unique nature and susceptibility to environmental damage. Among various restoration materials, calcium hydroxide (Ca(OH)2) has been widely studied and applied in the protection of paper-based cultural relics. However, commercial Ca(OH)2 materials have issues such as a large particle size and slow carbonation. In order to address these issues, this study employed carboxymethyl cellulose (CMC) as a support, on which nano-sized Ca(OH)2 crystals were grown in situ on its surface, followed by loading with TiO2 nanoparticles, successfully preparing a multifunctional paper-based cultural relic restoration material with reinforcement, deacidification, anti-aging, and antimicrobial properties. It is worth noting that by in situ growing Ca(OH)2 on the surface of CMC, particle size control, uniform dispersion, and the fixation of Ca(OH)2 can be achieved. CMC is used to enhance the mechanical strength of the paper, Ca(OH)2 is used for deacidification, and TiO2 is used for anti-aging and antimicrobial purposes. This study provides a new approach and method for the restoration of paper-based cultural relics, simplifying traditional multi-step processes and avoiding potential impacts on the cultural relics from multiple repairs.

Lignin-Assisted local release of triiodothyronine in adipose tissue protects mice against obesity and related metabolic disorders

Lignin is considered a promising carrier for drugs with aromatic structures via co-self-assembly, endowing the composite particles with functional properties for biomedical applications. Triiodothyronine (T3) has exhibited beneficial effects in obesity and obesity-related metabolic disorders by increasing the energy expenditure of adipose tissue; however, excess thyroid hormones may adversely affect various tissues. T3, which contains benzene rings and hydrophilic functional groups, is co-self-assembled with lignin to fabricate composite lignin–triiodothyronine (L-T3) particles using solvent-shifting methods. The dual driving forces of hydrogen bonding and π–π interactions enhance the co-self-assembly tendency of lignin and T3, thereby improving their distributions in the composite particles. L-T3 can be taken up by adipocytes with well controlled particle size. Moreover, a single locally delivered L-T3 dose to the subcutaneous white adipose tissue (sWAT) of mice does not affect mouse plasma T3 levels, but decreases the adipocyte size and increases uncoupling protein (UCP-1) expression in the sWAT of normal diet and short-term high-fat diet (HFD)-fed mice. Notably, L-T3 decreases body and adipose tissue weights in long-term HFD-fed mice. Furthermore, HFD-induced liver steatosis is substantially ameliorated by local delivery of L-T3 to sWAT. These results suggest that local delivery of L-T3 in adipose tissue exhibits protective effects against obesity and related metabolic disorders.

Effects of solid electrolyte particle size and silver-carbon interlayer on lithium deposition in all-solid-state lithium-metal batteries

All-solid-state batteries with lithium-metal anodes are expected to exhibit high performance. For practical application, the growth of lithium dendrites must be suppressed. One method to suppress dendrite growth is to insert a carbon interlayer at the interface between the anode and solid electrolyte (SE). Dendrite growth is related to the anode interface properties and depends on the SE particle size used in the SE layer. Appropriate control of the SE particle size used at the anode interface can improve battery performance. In this study, the effects of SE particle size and carbon interlayer type on lithium-metal deposition morphology are investigated by X-ray CT measurement. The results show that dendrite growth is suppressed when the small-particle SE is used owing to the smaller pores between the SE layer and carbon interlayer. In addition, by controlling the SE particle size distribution using a double SE layer, both high ionic conductivity and dendrite suppression can be achieved. Furthermore, dendrite growth can be suppressed using a silver particle-added carbon interlayer, even with the large-particle SE where dendrites are prone to grow more easily.

Control of the rubber particle size and phase structure for the design of transparent methacrylate-acrylonitrile-butadiene-styrene resin with excellent performance

Control of the rubber particle size and phase structure for the design of transparent methacrylate-acrylonitrile-butadiene-styrene resin with excellent performance

Nanosuspension as a Novel Nanovehicle for Drug Delivery: A Recent Update on Patents and Therapeutic Applications

Abstract: Solubility is a critical factor for the therapeutic action of drugs and does not depend on the administration of routes. Various conventional methods are used to enhance the solubility of the drug, which show limited applicability. Nanotechnology is used to improve the solubility and bioavailability of drugs that belong to BCS classes II and IV. Nanosuspension is the dispersion of pure drug nanoparticles in aqueous with a minimum amount of surfactant, stabilizing the formula-tion. Various techniques, such as the bottom-up approach, dissocubes, nanopure, nanoedge, nano-jet process, supercritical fluid, dry co-grinding, milling media, and nanoprecipitation, have been used to formulate nanosuspension. Nanosuspension can be administered orally, inhalation, trans-dermal, ocular, injectable, topical, and pulmonary. To resolve the problem of solubility and stabil-ity, nanosuspension has received much attention because of its technical simplicity, cost-effectiveness, and ease of significant scale-up. Nanosuspension can control particle size surface charge properties and release the drug at specific sites at an optimal rate. Recently, more than 100 patents have been published on nanosuspension. This review article covers the different prepara-tion methods, formulation composition, marketed products, characterization, and recent patents on nanosuspension. The various benefits and evaluation of the parameters of nanosuspension are discussed briefly. This patent-based review will enhance the knowledge of control drug delivery and related patents on nanosuspension.

Enhanced electrochemical performance of the LiMn0.6Fe0.4PO4/C modified by secondary particle morphology control combined with primary particle size control

Enhanced electrochemical performance of the LiMn0.6Fe0.4PO4/C modified by secondary particle morphology control combined with primary particle size control

Effect of secondary metabolites from several leaf extracts on the green synthesized-ZnO nanoparticles

This study explores a green synthesis approach for zinc oxide nanoparticles (ZnO NPs) using eco-friendly leaf extracts from mango (Mangifera indica), kapok (Ceiba pentandra), and oil palm (Elaeis guineensis Jacq.) trees. The research investigates the effect of the extracts' secondary metabolites on the synthesized ZnO NPs. Qualitative analysis identified the presence of alkaloids, phenols, steroids, and saponins in varying concentrations within each extract. ZnO nanoparticles were successfully synthesized using all three extracts, confirmed by FT-IR spectroscopy with a characteristic Zn–O peak at 416.3 cm−1. XRD analysis revealed the crystalline structure of the nanoparticles, with an additional peak in ZnO_CPLE suggesting potential impurities. SEM images demonstrated the influence of secondary metabolites on particle size and morphology. ZnO_EGLE, containing both phenols and saponins, exhibited the smallest and most uniform nanoparticles (43.3 nm) compared to ZnO_CPLE (94.5 nm) and ZnO_MILE (74.9 nm). TEM analysis further supported these findings, highlighting the crucial role of phenols and saponins as capping agents in controlling particle size and agglomeration. This research suggests a promising green synthesis route for ZnO NPs using these leaf extracts, potentially tailoring particle properties based on the specific secondary metabolite profile.

Rational design of diblock copolymer enables efficient cytosolic protein delivery

Polymer-mediated cytosolic protein delivery demonstrates a promising strategy for the development of protein therapeutics. Here, we propose a new designed diblock copolymer which realizes efficient cytosolic protein delivery both in vitro and in vivo. The polymer contains one protein-binding block composed of phenylboronic acid (PBA) and N-(3-dimethylaminopropyl) (DMAP) pendant units for protein binding and endosomal escape, respectively, followed by the response to ATP enriched in the cytosol which triggers the protein release. The other block is PEG designed to improve particle size control and circulation in vivo. By optimizing the block composition, sequence and length of the copolymer, the optimal one (BP20) was identified with the binding block containing 20 units of both PBA and DMAP, randomly distributed along the chain. When mixed with proteins, the BP20 forms stable nanoparticles and mediates efficient cytosolic delivery of a wide range of proteins including enzymes, toxic proteins and CRISPR/Cas9 ribonucleoproteins (RNP), to various cell lines. The PEG block, especially when further modified with folic acid (FA), enables tumor-targeted delivery of Saporin in vivo, which significantly suppresses the tumor growth. Our results shall inspire the design of novel polymeric vehicles with robust capability for cytosolic protein delivery, which holds great potential for both biological research and therapeutic applications.

Review on Study of Nanoparticles in Brain Targeting for Treatment Of Alzheimer’s

Alzheimer’s disease (AD) is an irreversible neurodegenerative disorder, in which there is a progressive deterioration of intellectual and social functions, memory loss, personality changes and inability for self-care, and has become the fourth leading cause of death in developed countries. Pathogenesis of AD, there is a progressive deposition of β-amyloid (Aβ)- peptide in the hippocampal and cerebral cortical regions. This deposition is associated with the presence of neurofibrillary tangles (NFTs) and senile plaques. The senile plaques deposited between the neurons consist mainly protein β amyloid. Neurofibrillary tangles deposited inside the neurons fabricated from Tau protein. Diagnosing Alzheimer's requires careful medical evaluation thorough medical history, mental status testing, physical and neurological examination tests (such as blood tests and brain imaging), two classes of medications approved to treat AD. Cholinesterase inhibitors: Donepezil, Rivastigmine, Galantamine, NMDA receptor antagonists: Memantine. The major goal in designing nanoparticles as a delivery system are to control particle size, surface property and release of pharmacologically active agents in order to achieve the site-specific action of the drug at the therapeutic optimum rate and dose regimen of the agent to the CNS, but also the ability of the agent to access the relevant target site within the CNS. Many strategies have been developed to deliver the drug into brain by crossing the BBB: chemical delivery systems, magnetic drug targeting or drug carrier systems such as antibodies, liposomes or nanoparticles. Among those, nanoparticles have got a great concentration as the potential targeted drug delivery systems in the brain recently. Keywords: Alzheimer’s disease, β-amyloid, cholinesterase inhibitors, Curcumin nanoparticles.