Preparation Of Monodisperse Research Articles

Construction of highly stable, monodisperse water-in-water Pickering emulsions with full particle coverage using a composite system of microfluidics and helical coiled tube

Water-in-water (W/W) Pickering emulsions, exhibit considerable potential in the food and pharmaceutical fields owing to their compartmentalization and high biocompatibility. However, constrained by the non-uniform distribution of shear forces during emulsification or the spatial obstruction in polydimethylsiloxane (PDMS) passive microfluidic platform, the existing methods cannot generate monodisperse W/W Pickering emulsions with high particle coverage rate, thereby limiting their applications. Herein, a novel microfluidic system is designed for the preparation of monodisperse and highly particle-covered W/W Pickering emulsions under mild conditions. pH-responsive Polyethylene glycol (PEG)/phosphate aqueous two-phase system (ATPS) is used for the emulsions' preparation. Notably, a coverage rate of 96 ± 3 % is obtained by adjusting the length of the helical coiled tube, as well as the size and contact angle of genipin cross-linked BSA (BSA-GP) particles. Moreover, these W/W Pickering emulsions, with surfaces almost completely covered, can maintain monodisperse (Ncoal = 1.18 ± 0.03) for one day. Furthermore, the results of ranitidine hydrochloride (RH) release demonstrated that the drug release rate of W/W Pickering emulsions in the simulated gastric fluid (SGF) was 10 times faster than that in the neutral solution. We believe that the highly particle-covered monodisperse W/W Pickering emulsions possess great potential applications in bioencapsulation for foods and drug delivery.

Rapid plasma electrolytic oxidation preparation of sub-3 nm half-embedded intermetallic nanocatalysts for efficient selective hydrogenation

Monodisperse sub-3 nm ordered intermetallic nanoparticles half-embedded in a porous MgO support layer on a Mg plate were prepared for the first time.

Microfluidic preparation of monodisperse PLGA-PEG/PLGA microspheres with controllable morphology for drug release.

Monodisperse biodegradable polymer microspheres show broad applications in drug delivery and other fields. In this study, we developed an effective method that combines microfluidics with interfacial instability to prepare monodispersed poly(lactic-co-glycolic acid)-b-polyethylene glycol (PLGA-PEG)/poly(lactic-co-glycolic acid) (PLGA) microspheres with tailored surface morphology. By adjusting the mass ratio of PLGA-PEG to PLGA, the concentration of stabilizers and the type of PLGA, we generated microspheres with various unique folded morphologies, such as "fishtail-like", "lace-like" and "sponge-like" porous structures. Additionally, we demonstrated that risperidone-loaded PLGA-PEG/PLGA microspheres with these folded morphologies significantly enhanced drug release, particularly in the initial stage, by exhibiting a logarithmic release profile. This feature could potentially address the issue of delayed release commonly observed in sustained-release formulations. This study presents a straightforward yet effective approach to construct precisely engineered microspheres offering enhanced control over drug release dynamics.

Folate conjugated albumin as a targeted nanocarrier for the delivery of fisetin: in silico and in vitro biological studies.

Fisetin (FST), a natural flavonoid compound derived from various fruits and vegetables, including apple, strawberry, and onion, demonstrates potential for a wide range of pharmaceutical applications, including potential anticancer properties. However, challenges such as low bioavailability, poor aqueous solubility, and limited permeability restrict the use of FST in the pharmaceutical sector. Nowadays, targeted nanomedicines have garnered attention to overcome limitations associated with phytochemicals, including FST. In the present study, we have designed and successfully prepared folate-targeted FST nanoparticles (FFNPs). Characterization through DLS and FE-SEM revealed the successful preparation of monodisperse (PDI: 0.117), nanoscale-sized (150 nm), and spherical nanoparticles. Physicochemical characterization including FTIR, XRD, DSC, and TGA analysis, confirmed the encapsulation of the FST within the Folic acid (FA) - conjugated nanoparticles (CNPs) and revealed its amorphous nature. Molecular docking analysis revealed the strong binding affinity and specific amino acid interactions involved in the BSA-FST-FA complex, suggesting the potential synergistic effect of FST and FA in enhancing the therapeutic activity of the FFANPs. Cytotoxic assessments by the MTT assay, migration assay, AO-EtBr staining assay, colony formation assay, and cellular uptake study demonstrated enhanced anticancer efficacy, apoptosis induction, and enhanced uptake of FFNPs compared to pure FST. These findings propose prepared FFNPs as a promising targeted drug delivery nanocarrier for effective FST delivery in cancer therapy.

Facile Preparation of Monodisperse Cu@Ag Core-Shell Nanoparticles for Conductive Ink in Printing Electronics.

Copper-based nanoinks are emerging as promising low-cost alternatives to widely used silver nanoinks in electronic printing. However, the spontaneous oxidation of copper under ambient conditions poses significant challenges to its broader application. To address this issue, this paper presents an economical, large-scale, and environmentally friendly method for fabricating Cu@Ag nanoparticles (Cu@Ag NPs). The as-prepared nanoparticles exhibit a narrow size distribution of approximately 100 nm and can withstand ambient exposure for at least 60 days without significant oxidation. The Cu@Ag-based ink, with a 60 wt% loading, was screen-printed onto a flexible polyimide substrate and subsequently heat-treated at 290 °C for 15 minutes under a nitrogen atmosphere. The sintered pattern displayed a low electrical resistivity of 25.5 μΩ·cm (approximately 15 times the resistivity of bulk copper) along with excellent reliability and mechanical fatigue strength. The innovative Cu@Ag NPs fabrication method holds considerable potential for advancing large-scale applications of copper-based inks in flexible electronics.

In situ preparation of monodisperse lignin-poly (lactic acid) microspheres for efficient encapsulation of 2,4-dichlorophenoxyacetic acid and controlled release

Pesticide-controlled release systems play a key role in reducing the use of pesticides and extending the lifetime of active ingredients and are therefore essential for environmental protection. Herein, composite microspheres (2,4-D@AL-PLA) loaded with 2,4-dichlorophenoxyacetic acid (2,4-D) were prepared in situ by emulsification-solvent volatilization using lignin-modified poly (lactic acid) as the precursor materials (AL-PLA). The rigid characteristics and three-dimensional structure of lignin macromolecules not only make the surface of 2,4-D@AL-PLA smooth, round and monodisperse but also endow them with a distinct porous skeleton and typical cavities. Accordingly, the 2,4-D@AL-PLA exhibited high efficiency in pesticide loading (45.43 wt%) and encapsulation (87.87%). Hydrogen bonding between lignin and PLA played a key role in controlling the release of 2,4-D from microsphere and imparted pH/temperature-responsive release properties to the model molecules. Kinetic studies showed that the release of 2,4-D followed a first-order kinetic model and the release mechanism was Fick diffusion, i.e., where the 2,4-D molecule achieved diffusion from the porous backbone of the microspheres. Moreover, the bioactivity test showed that the 2,4-D-loaded microspheres could effectively inhibit the growth of dicotyledonous weeds. This work provides a new way for designing environmentally friendly pesticide controlled-release systems and opens up new possibilities for applications in pesticide delivery.

Preparation of monodisperse water-in-oil emulsions using microchannel homogenization

The droplet size and uniformity of water-in-oil (W/O) emulsions are important properties governing their stability in diverse applications. Monodisperse emulsions are preferred over polydisperse emulsions because their droplet size and distribution are easier to control. Here, we prepared (relatively) monodisperse W/O emulsions using microchannel homogenization (MCH) with an asymmetric straight-through microchannel (MC) array chip. Numerous asymmetric straight-through MCs, each comprising a microslot and circular microhole (diameter: 10 µm), were microfabricated on a silicon-on-insulator chip. We investigated the effects of emulsifier concentration, continuous-phase viscosity, dispersed-phase volume fraction, and the operating pressure of coarse W/O emulsions on the preparation of W/O emulsions, droplet size, and size distribution. The continuous phase was composed of soybean or medium-chain triglyceride oil solutions with tetraglycerin monolaurate condensed ricinoleic acid ester as the emulsifier. The dispersed phase was a Milli-Q water solution containing NaCl and/or polyethylene glycol (m.w. 20,000). The results demonstrate the suitability of MCH for the preparation of monodisperse W/O emulsions with an average droplet diameter of 12–15 µm and 8% lowest coefficient of variation using hydrophobically surface-treated asymmetric straight-through MCs with appropriately selected emulsion compositions and operating conditions.

Preparation and application of monodisperse, highly cross-linked, and porous polystyrene microspheres for dye removal

The porous materials as adsorbents play an important role in dye removal. In this paper, monodisperse, highly cross-linked porous microspheres with a specific surface area of 255.83 m²/g and average pore size of 8.5 nm were synthesized by seed swollen emulsion polymerization. The sulfonation reactions of porous microspheres were carried out to improve the hydrophilic performance and electronegativity of the microsphere surface. Cationic methylene blue (MB) and anionic methyl orange (MO) were employed as simulated dye wastewater to investigate the adsorption kinetics of porous microspheres. The experimental results demonstrate that porous sulfonate microspheres possess selective adsorption for MB due to electrostatic interaction between the negative charges on the surface of microspheres and the positive charges of MB molecules. Porous microspheres exhibit an adsorption capacity of 313.125 mg/g after 2 h. The adsorption kinetics of MB dyes in porous microspheres follow a pseudo-second-order model.

Polyacids for producing colloidally stable amorphous calcium carbonate clusters in water

AbstractAs an important precursor of crystalline phases, amorphous calcium carbonate (ACC), especially ultrasmall ACC clusters, have been attracting great interest in fundamental research, materials chemistry, as well as industrial applications. However, it is still challenging to synthesize stable ACC clusters in water that can be isolated and concentrated without severe aggregation. Herein, we report a facile dialysis method for producing colloidally stable ACC clusters that are well dispersed in water with the protection of specific polycarboxylic acids, which could be also easily deprotected by small‐molecule acids like sodium citrate. Inherent proto‐calcite short‐range order is found to be present in all the obtained ACC clusters. The present strategy not only allows for the preparation of monodisperse isolated ACC clusters in aqueous solution but also shows great potential in industrial uses like waste water treatment.

Ionic gelation of chitosan with sodium tripolyphosphate using a novel combined nebulizer and falling film system

AbstractNanoparticle technology has made an essential contribution to the pharmaceutical industry and has received considerable attention in comparison with the other domains. In the present study, ionic gelation via a novel combined system of nebulizer and falling film (IG‐NFF) has been proposed. The purpose of the design of this system is to increase the contact surface between the chitosan and sodium tripolyphosphate (STPP) for the preparation of monodisperse and spherical chitosan nanoparticles, because in both nebulizer and falling film systems, the surface‐to‐volume ratio of liquid increases. The formation of these nanoparticles is based on ionic interactions between the negatively charged phosphate groups in the STPP and positively charged amine groups on the chitosan. In this research, the effects of chitosan concentration, STPP concentration, the distance of the nebulizer from the inclined plate, gas to liquid flow rate ratio, and the initial chitosan solution pH on the z‐average size, polydispersity index (PDI), and morphology of nanoparticles formed by IG‐NFF were studied. The results showed that the IG‐NFF process has the ability to produce spherical particles with highly uniform sizes. The mean size of obtained chitosan nanoparticles was in the range of 80–320 nm, and the PDI value ranged from 0.08–0.30.

Preparation of monodisperse, restricted-access, media-molecularly imprinted polymers using bi-functional monomers for solid-phase extraction of sarafloxacin from complex samples

Monodisperse restricted-access media bi-functional monomers with molecularly imprinted polymers (RAM-MIPs) were constructed using surface-initiated atom transfer radical polymerization. They were used as solid-phase extraction (SPE) adsorbents to enrich sarafloxacin (SAR) residues from egg samples, and influences on their performance were investigated. Optimum synthesis of RAM-MIPs was achieved by combining a bi-functional monomer (4-vinylpyridine-co-methacrylic acid, 1:3) with an 8:1:32:8 ratio of a template molecule, cross-linker, and restricted-access functional monomer. The SAR imprinting factor of RAM-MIPs was 6.05 and the selectivity coefficient between SAR and other fluoroquinolones was 1.86–2.64. Compared with traditional MIPs, the RAM-MIPs showed better SAR enrichment and selectivity during extraction of a complex protein-containing solution. Empty SPE cartridges were filled with RAM-MIP microspheres as SPE adsorbents. The limit of quantitation for SAR was 4.23 ng g−1 (signal-to-noise ratio = 10) and the mean SAR recovery from spiked egg samples was 94.0–101.3%. Intra-day and inter-day relative standard deviations were 1.1–9% and 1.5–3.3%, respectively.

Preparation of monodisperse S/W/O compound droplets with thick liquid film via a dual-cross microfluidic device

Double-layer polymer shells with stringent specifications are always employed as the inertial confinement fusion (ICF) targets, which can be prepared by solidifying the solid-in-water-in-oil (S/W/O) compound droplets. A microfluidic device with a dual-cross structure is proposed to improve the quality of the resulting S/W/O compound droplets, and further, the formation process is extensively investigated. Especially, the flow regimes of multiple-encapsulation can be avoided when compared with the flow-focusing microfluidic device, and the thickness of the polyvinyl alcohol (PVA) liquid film coated onto the solid particle is also improved because of the large interval distance between sequenced solid particles. Moreover, the influences of both phases’ flow rates on the thickness of the liquid layer are also discussed. With the decrease of the flow rate ratio of the continuous phase to the dispersed phase, the thickness of the PVA liquid film rises from 55 to 383 µm, and the coefficient of variation (CV) of the liquid film thickness is about 4%. Increase the diameter of the main channel to obtain a thicker liquid film range from 122 to 648 µm. The obtained results could provide experimental guidance to prepare S/W/O compound droplets precisely and controllably with a specific thickness of the liquid layer.

Protein-Stabilized Palm-Oil-in-Water Emulsification Using Microchannel Array Devices under Controlled Temperature.

Microchannel (MC) emulsification for the preparation of monodisperse oil-in-water (O/W) and water-in-oil-in-water (W/O/W) emulsions containing palm oil as the oil phase was investigated for application as basic material solid/semi-solid lipid microspheres for delivery carriers of nutrients and drugs. Emulsification was characterized by direct observation of droplet generation under various operation conditions, as such, the effects of type and concentration of emulsifiers, emulsification temperature, MC structure, and flow rate of to-be-dispersed phase on droplet generation via MC were investigated. Sodium caseinate (SC) was confirmed as the most suitable emulsifier among the examined emulsifiers, and monodisperse O/W and W/O/W emulsions stabilized by it were successfully obtained with 20 to 40 µm mean diameter (dm) using different types of MCs.

High‐throughput, aseptic production of injectable Tetra‐PEG hydrogel microspheres for delivery of releasable covalently bound drugs

AbstractThe purpose of this work was to develop equipment and procedures for large‐scale aseptic production of injectable microsphere (MS) drug conjugates. The two major challenges were (a) to prepare sufficient amounts of MSs for clinical trials, and (b) to prepare the MS‐drug product under aseptic conditions. The approach was to prepare the MS‐drug conjugate in two stages. Stage 1 was the preparation of monodisperse tetra‐PEG amine derivatized MSs (amino‐MS) from two soluble PEG prepolymers under low to no bioburden conditions. To accomplish this, custom‐engineered equipment compatible with both aqueous and organic solvents was fabricated for parallel microfluidic preparation of amino‐MS. The system was capable of preparing up to ∼2 L of high quality 50 μm diameter amino‐MS per day. Stage 2 was the sterilization of the starting amino‐MS and aseptic production of the MS‐drug conjugate. The amino‐MS were first sterilized by autoclaving then transferred to a custom‐engineered autoclave‐sterilized washer‐reactor. This apparatus allowed for activation of the amino‐MS and attachment of a linker‐drug under aseptic conditions to give the sterile MS‐drug conjugate drug substance. The final drug product was produced by addition of excipients to form a homogeneous suspension. The entire process is exemplified by an engineering production run of a sterile MS‐peptide drug product.

The preparation of monodisperse P(St-BA-MAA)@disperse dye microspheres and fabrication of patterned photonic crystals with brilliant structural colors on white substrates

The black disperse dye and poly (styrene-butyl acrylate-methacrylic acid) (P(St-BA-MAA)) seed microspheres synthesized by soap-free emulsion copolymerization are regarded as main components to prepare P(St-BA-MAA)@disperse dye composite microspheres (@ means the dye is loaded on the microsphers). The influences of the concentrations of disperse dye, the concentrations of P(St-BA-MAA) seed microspheres and the preparation temperature on diameters and monodispersity of P(St-BA-MAA)@disperse dye microspheres are deeply investigated, and the prepared P(St-BA-MAA)@disperse dye microspheres are acted as the structural units to construct photonic crystals with structural colors on fabric substrates by ink-jet printing technology. Especially, the resultant photonic crystals and structural colors are detailedly characterized, and the comparison of self-assembly effect between P(St-BA-MAA)@disperse dye microspheres and pure P(St-BA-MAA) microspheres are depicted. The results showed that the monodisper P(St-BA-MAA)@disperse dye microspheres with different diameters ranging from 180 nm to 350 nm could be prepared by adjusting the concentrations of disperse dye and P(St-BA-MAA) seed microspheres and the preparation temperature. The P(St-BA-MAA)@disperse dye photonic crystals with FCC structure are regular and orderly, showing a bright and iridescent structural colors. Black disperse dye in composite microspheres plays a role in the absorption of stray light, and the structural color effect of P(St-BA-MAA)@disperse dye photonic crystals is better than pure P(St-BA-MAA) photonic crystals on white substrates. It is concluded that this research will offer theoretical basis and practical guidance for the fabrication of photonic crystals with brilliant structural colors on white substrates.

Monodisperse Liquid Crystal Network Particles Synthesized via Precipitation Polymerization.

The production of liquid crystalline (LC) polymer particles with a narrow size distribution on a large scale remains a challenge. Here, we report the preparation of monodisperse, cross-linked liquid crystalline particles via precipitation polymerization. This versatile and scalable method yields polymer particles with a smectic liquid crystal order. Although the LC monomers are randomly dissolved in solution, the oligomers self-align and LC order is induced. For the polymerization, a smectic LC monomer mixture consisting of cross-linkers and benzoic acid hydrogen-bonded dimers is used. The average diameter of the particles increases at higher polymerization temperatures and in better solvents, whereas the monomer and initiator concentration have only minor impact on the particle size. After deprotonating of the benzoic acid groups, the particles show rapid absorption of a common cationic dye, methylene blue. The methylene blue in the particles can be subsequently released with the addition of Ca2+, while monovalent ions fail to trigger the release. These results reveal that precipitation polymerization is an attractive method to prepare functional LC polymer particles of a narrow size distribution and on a large scale.

Preparation of monodisperse O/W emulsions using a crude surface-active extract from argan by-products in microchannel emulsification

In this study, we evaluated the performance of a mildly derived extract from argan by-products in microchannel emulsification (MCE). Our aim is to produce stable monodisperse O/W emulsions using this extract as a sole emulsifier. Preliminary investigations about the characteristics of argan extract indicated the potential interaction between surface-active components (i.e. saponins, proteins), in bulk phase prior to adsorption at the oil/water interface, resulting in the formation of biogenic complexes with strong interfacial properties. This is important for successful MCE as this technique depends exclusively on dynamic interfacial tension reduction for droplet formation. Nevertheless, upon performance of emulsification experiments, we also found that the complex composition of this extract could counteract its emulsifying efficiency, by creating a hydrophobic, or slightly hydrophilic, layer on the MC array plate surface. This resulted in unsuccessful emulsification using short MCs but did not affect the emulsification behavior in longer ones. Using longer MCs, we could produce stable monodisperse O/W emulsions, with similar droplet size (∼ 36 μm) and droplet size distribution (Relative span factor <0.25) to those obtained using Tween 80, and for up to 10 h of continuous emulsification.

Monodisperse and Uniform Mesoporous Silicate Nanosensitizers Achieve Low-Dose X-Ray-Induced Deep-Penetrating Photodynamic Therapy.

X-ray-induced photodynamic therapy (X-PDT) combines both the advantages of radiotherapy (RT) and PDT, and has considerable potential applications in clinical deep-penetrating cancer therapy. However, it is still a major challenge to prepare monodisperse nanoscintillators with uniform size and high light yield. In this study, a general and rapid synthesis method is presented that can achieve large-scale preparation of monodisperse and uniform silicate nanoscintillators. By simply adjusting the metal dopants, silicate nanoscintillators with controllable size and X-ray-excited optical luminescence (450-900 nm) are synthesized by employing a general ion-incorporated silica-templating method. To make full use of external radiation, the silicate nanoscintillators are conjugated with photosensitizer rose bengal and arginylglycylaspartic acid (RGD) peptide, making them intrinsically dual-modal targeted imaging probes. Both in vitro and in vivo experiments demonstrate that the silicate nanosensitizers can accumulate effectively in tumors and achieve significant inhibitory effect on tumor progression under low-dose X-ray irradiation, while minimally affecting normal tissues. The insights gained in this study may provide an attractive route to synthesize nanosensitizers to overcome some of the limitations of RT and PDT in cancer treatment.

Narrow or Monodisperse, Physically Cross-Linked, and “Living” Spherical Polymer Particles by One-Stage RAFT Precipitation Polymerization

Controlled preparation of narrow or monodisperse, physically cross-linked, and “living” spherical polymer particles by one-stage reversible addition–fragmentation chain transfer (RAFT) precipitation polymerization (RAFTPP) is described for the first time. The introduction of RAFT polymerization mechanism into precipitation polymerization system, together with the use of methacrylic acid (MAA) (capable of forming hydrogen bonding) as the monomer, allows ready generation of uniform spherical poly(MAA) (PMAA) particles with surface-bound “living” dithioester groups, easily tunable sizes, and low molecular weights in the absence of any cross-linking monomer. The polymerization parameters (i.e., monomer loading, molar ratio of the RAFT agent to free radical initiator, and polymerization temperature) showed much influence on the morphologies and yields of PMAA particles, and their simple adjustment allows fine-tuning of “living” PMAA particle sizes. The presence of dithioester groups on such PMAA particles was ...

Preparation of monodisperse fully aromatic polyimide particles via the polycondensation of diethyl hexafluoroisopropylidenediphthalate with 4,4′-diaminodiphenylether in ethylene glycol

Fully aromatic polyimide particles were obtained in a single step via the polycondensation of diethyl (hexafluoroisopropylidene)diphthalate (6FE) and 4,4′-oxydianiline (ODA) using polyvinylpyrrolidone (PVP) as a steric stabilizer in ethylene glycol. Since the monomers are soluble in ethylene glycol, but the polyimide is insoluble, the polyimide particles grew gradually during the polycondensation process. The particle size and size distribution were controlled by varying the molecular weight and amounts of PVP. The particle size decreased with both increasing concentration and increasing molecular weight of the stabilizer. Furthermore, the solvent composition affected the particle size, i.e., the particle size decreased with increasing volume of glycerol as a cosolvent. Monodisperse particles (diameter: 8.5–1.8 μm) were obtained by varying the amounts of PVP and glycerol. Fully aromatic polyimide particles were obtained in a single step via the polycondensation of diethyl (hexafluoroisopropylidene)diphthalate and 4,4’-oxydianiline using polyvinylpyrrolidone (PVP) as a steric stabilizer in ethylene glycol. Since the monomers are soluble in ethylene glycol, but the polyimide is insoluble, the polyimide particles grew gradually during the polycondensation process. The particle size and size distribution were controlled by varying the molecular weight and amounts of PVP.