Surface Of Microparticles Research Articles

Cryopreserved buffy-coat-derived platelets reconstituted in platelet additive solution: A safe and available product with sufficient haemostatic effectiveness

BackgroundPlatelets (PLTs) stored at 20–24 °C have a short shelf life of only 5 days, which can result in their restricted availability. PLT cryopreservation extends the shelf life to 2 years. MethodsWe implemented a method of PLT freezing at −80 °C in 5–6% dimethyl sulfoxide. Buffy-coat-derived leucodepleted fresh PLTs blood group O (FP) were used for cryopreservation. Cryopreserved pooled leucodepleted PLTs (CPP) were thawed at 37 °C, reconstituted in PLT additive solution SSP + and compared to FP regarding PLT content, PLT concentration, pH, volume, PLT loss, anti-A/B antibody titre, total protein, plasma content, and PLT swirling. Clot properties were evaluated via rotational thromboelastometry. PLT microparticle number and surface receptor phenotype were assessed via flow cytometry. ResultsCPP met the required quality parameters. The mean freeze-thaw PLT loss was 22.24 %. Anti-A/B antibody titre and plasma content were significantly lower in CPP. CPP were characterised by faster clot initiation and form stable PLT clots. The number of PLT microparticles increased 25 times in CPP and there were more particles positive for the activation marker CD62 P compared to FP. ConclusionThawing and reconstitution are easy and fast processes if platelet additive solution is used. Low anti-A/B antibody titre and plasma content make possible the use of CPP of blood group O reconstituted in SSP + as universal ABO products, including clinical situations where washed PLTs are required. Clot properties evaluated via rotational thromboelastometry demonstrated that CPP retain a significant part of their activity compare to FP and are haemostatically effective.

Complex coacervation of pea protein isolate and tragacanth gum: Comparative study with commercial polysaccharides

The ability of pea protein isolates (PPI) to form complex coacervates with tragacanth gum was investigated. The coacervate formation was structurally compared to three other PPI-polysaccharide interaction models: arabic gum and sodium alginate (known to form coacervates with PPI) and tara gum, a galactomannan. The effects of the pH and protein/polysaccharide ratio were mainly investigated using turbidity and zeta potential measurements. Regarding the pH of soluble complex formation, the pH of complex coacervates increased with the increase in protein-anionic polysaccharide mixture ratio. SEM images revealed the ability of the spray-drying process to form spherical particles of pea protein-polysaccharide complexes. The specificity of the microparticle surface was protein-dependent. FTIR analyses of coacervates showed the electrostatic interaction between the PPI and the polysaccharides. The results showed that tragacanth gum could be used as an alternative to gum arabic to form complex coacervates with PPI based on zeta potential measurements and coacervation yield studies.

Hematite/Polystyrene Raspberry‐Like Microcomposites as Stable Support for Silver Nanoparticle Immobilization

AbstractAmong the methods utilized for the preparation of raspberry‐like microcomposites, due to its simplicity and universality, the electrostatically‐driven deposition of nanoparticles at the surface of microparticles is especially attractive. This process, leading to the formation of a single nanoparticle monolayer, is widely reported. On the other hand, no data concerning the electrostatically‐driven formation of nanoparticle bilayers at the surface of microparticles are reported. To fill this gap, the detailed investigation of the formation of silver/hematite nanoparticle bilayers at the surface of polystyrene microparticles is reported. First, the hematite/polystyrene raspberry‐like microcomposites are obtained by immobilization of hematite nanoparticles under an electrostatically‐driven process. The stability of hematite/polystyrene microcomposites at elevated temperatures up to 323 K is monitored using microelectrophoresis. No significant changes in the hematite nanoparticle layer coverage are observed after prolonged time of incubation. This proves the irreversible character of nanoparticle immobilization. Next, the hematite/polystyrene microcomposites are utilized as the interfaces for immobilization of negatively charged silver nanoparticles. This process is quantitatively described using electrokinetic measurements. The changes in the hydrodynamic diameter of microcomposites are also determined. Finally, the validity of the electrokinetic model used in this work for predicting the zeta potential of the silver/hematite/polystyrene microcomposites is confirmed.

Vortex Formation and Separation from the Surface of a Charged Dielectric Microparticle in a Strong Electric Field

—The motion of a charged dielectric microparticle in an electric field is first studied over a wide parameter range on the base of the numerical solution of the system of Nernst–Planck–Poisson–Stokes equations. As the most important result, the formation of microvortices on the rear side of the particle is revealed. The microvortices lose their steadiness with increase in the electric field strength and separate periodically from the particle surface. Separation becomes chaotic with further increase in the electric field strength. The phenomenon strongly resembles the formation of the Karman street but it has another physical mechanism by virtue of almost zero Reynolds numbers of micro- and nanoparticle flow. The asymptotic analysis is carried out and the mechanism of microvortex formation and separation is theoretically substantiated at small Debye numbers.

Bleached shellac in situ forming micro-particle fabricated with different oils as antibacterial delivery system for periodontitis treatment

In-situ forming micro-particle (ISM) is an emulsion system that could change into micro-particulate matrices by phase separation of matrix former. In this research work, bleach shellac (BS) was used as the matrix forming agent to develop the doxycycline hyclate (DH)-loaded ISM and the different oils were used as the external phase of non-aqueous in oil emulsion. ISMs were prepared by using BS dissolved in dimethyl sulfoxide (DMSO), N-methyl pyrrolidone (NMP), or 2-pyrrolidone (PYR) as the internal phase and the external phase containing glycerol monosterate (GMS) in various oils including camellia oil, canola oil, olive oil, safflower oil, and sesame oil. The physical properties of ISMs using PYR as the solvent of the internal phase were tested including viscosity, in vitro micro-particle formation, injectability, drug release, surface topography, and antibacterial activity against Porphyrommonas gingivalis. All DH-loaded ISMs were easy to be injected through a needle and formed into micro-particles after exposure to phosphate buffer. The external oil phase reduced the friction between barrel and plunger of syringe and thus promoting easier injectability. The particular drug-loaded ISM prepared from safflower oil was largest, while that prepared from sesame oil was smallest and that of the others had no significant difference (p < 0.05). After 60 sec, the particle size of drug-loaded formula had no presence of coalescence. DH released from BS ISM was sustainable longer than 50 days. Sponge topography of micro-particle after DH release test in SEM micrographs confirmed the solvent exchange initiated further phase separation of BS into a micro-particular sponge. They efficient inhibited against P. gingivalis with a sustainable drug release character from the retardation of drug diffusion. Thus, DH-loaded ISMs using PYR as the solvent of the internal phase could be fabricated with various oils and exhibited the potential use for periodontitis treatment.

A Novel Pool of Microparticle Cholesterol Is Elevated in Rheumatoid Arthritis but Not in Systemic Lupus Erythematosus Patients

Microparticles are sub-micron, membrane-bound particles released from virtually all cells and which are present in the circulation. In several autoimmune disorders their amount and composition in the circulation is altered. Microparticle surface protein expression has been explored as a differentiating tool in autoimmune disorders where the clinical pictures can overlap. Here, we examine the utility of a novel lipid-based marker—microparticle cholesterol, present in all microparticles regardless of cellular origin—to distinguish between rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE). We first isolated a series of microparticle containing lipoprotein deficient fractions from patient and control plasma. There were no significant differences in the size, structure or protein content of microparticles isolated from each group. Compared to controls, both patient groups contained significantly greater amounts of platelet and endothelial cell-derived microparticles. The cholesterol content of microparticle fractions isolated from RA patients was significantly greater than those from either SLE patients or healthy controls. Our data indicate that circulating non-lipoprotein microparticle cholesterol, which may account for 1–2% of measured cholesterol in patient samples, may represent a novel differentiator of disease, which is independent of cellular origin.

Synthesis of superacid sulfated TiO2 prepared by sol-gel method and its use as a titania precursor in obtaining a kaolinite/TiO2 nano-hybrid composite

Superacid sulfated TiO2 was prepared by the sol-gel method and tested as a titania precursor to obtaining a kaolinite/TiO2 nano-hybrid composite. Raman, FTIR, Zeta Potential, and XRD analyses allowed the identification of kaolinite and titania as well as the interactions between them to form the nanohybrid composite. SEM-FEG/TEM analyses clearly showed titanium nanocrystals adhered to the surface of kaolinite microparticles. Thermogravimetric analysis of the powders showed that the composite obtained has a tenuous thermal reinforcement due to the presence of TiO2. Furthermore, the composite has excellent photocatalytic activity, reaching up to about 97% of methylene blue degradation under UV-C radiation in 3 h. Therefore, this study proposes a simple, safe, and effective method for the use of sulfated TiO2 as a precursor in the synthesis of composite nanomaterials based on titania.

Enhancement of selective adsorption of Cr species via modification of pine biomass

Pine biomass (Pine), pine gasification biochar (PG) and pine biomass loaded with TiO2 (Pine/TiO2) were used as sorbent materials to remove Cr(III) or Cr(VI) ions from aqueous solutions. Our results showed that Pine/TiO2 had an improved adsorption capacity respect to Pine being the adsorption capacity for Cr(VI), 12.8 mg/g, much larger than for Cr(III), 1.23 mg/g. On the other hand, PG showed much higher adsorption for Cr(III), 12.4 mg/g, than Pine/TiO2, and negligible adsorption for Cr(VI). To understand this species-dependent adsorption behavior, the adsorption mechanisms, sorbents morphology and functional sites were characterized using a multi-technique approach. The chemical state and local coordination structure of the adsorbed Cr species was studied by X-ray absorption spectroscopy (XAS). Our results show that the adsorption of Cr(III) occurred mainly through cation exchange with mineral elements in PG biochar, whereas the Cr(III) adsorption by functional groups (carboxyl and hydroxyl groups) dominate in the biomass sorbent. The enhancement of Cr(VI) adsorption in Pine/TiO2 can be explained by the presence of TiOH2+groups present in the surface of the TiO2 microparticles. X-ray absorption spectroscopy (XAS) results reveal that Cr(VI) reduces to Cr(III) after being adsorbed by the sorbent materials.

Microfluidic-Based Detection of AML-Specific Biomarkers Using the Example of Promyelocyte Leukemia.

A microfluidic assay for the detection of promyelocytic leukemia (PML)-retinoic acid receptor α (RARα) fusion protein was developed. This microfluidic-based system can be used for rapid personalized differential diagnosis of acute promyelocyte leukemia (APL) with the aim of early initiation of individualized therapy. The fusion protein PML-RARα occurs in 95% of acute promyelocytic leukemia cases and is considered as diagnostically relevant. The fusion protein is formed as a result of translocation t(15,17) and is detected in the laboratory by fluorescence in situ hybridization (FISH) or reverse transcriptase polymerase chain reaction (RT-PCR). Diagnostic methods require many laboratory steps with specialized staff. The developed microfluidic assay includes a sandwich enzyme-linked immunosorbent assay (ELISA) system for PML-RARα on surface of magnetic microparticles in a microfluidic chip. A rapid detection of PML-RARα in cell lysates is achieved in less than one hour. A biotinylated PML-antibody on the surface of magnetic streptavidin coated microparticles is used as capture antibody. The bound translocation product is detected by a RARα antibody conjugated with horseradish peroxidase and the substrate QuantaRed. The analysis is performed in microfluidic channels which involves automated liquid processing with stringent washing and short incubation times. The results of the developed assay show that cell lysates of PML-RARα-positive cells (NB-4) can be clearly distinguished from PML-RARα-negative cells (HL-60, MV4-11).

Preparation and characterization of superhydrophobic PVDF/HMSNs hybrid membrane for CO2 absorption

Superhydrophobic polyvinylidene fluoride (PVDF) membranes were prepared via incorporated with hydrophobic modified SiO2 nanoparticles (HMSNs). Results demonstrated that HMSNs in the dope induced precipitation of PVDF, mainly by solid-liquid demixing in ethanol bath. The fabricated superhydrophobic PVDF/HMSNs hybrid membrane was showed uniformly skinless comprising of PVDF spherical microparticles. During preparation, the HMSNs attach onto the PVDF microsphere surfaces as-formed micro-nano structures, which was important for imparting membrane superhydrophobicity. Therefore, the water contact angle of PVDF/HMSNs hybrid membrane was 155° as the mass ratio of HMSNs with PVDF matrix was 0.15:1 when ethanol coagulation bath was used. Since the proposed modification allowed HMSNs migration onto PVDF spherical microparticles surfaces during the exchange between solvent and non-solvent, the hydrophobicity of internal surface of membrane pores and channels was also enhanced. This feature successfully inhibited the liquid intrusion into membrane pores, and guaranteed a stable anti-wettability over a long period. The absorption flux was 2.34 mmol m−2 s−1 for prewetted as the mass ratio of HMSNs with PVDF matrix was 0.15:1 with a fluid flow rate of 240 mL min−1, 3.3 times higher than the prewetted pristine PVDF membrane. These results show that PVDF/HMSNs hybrid membranes are ideal candidates for application in CO2 absorption.

Effect of collision on self-assembly of nanoparticles in zirconia microparticle suspension

Nanoparticle halo mechanism is a stabilization method for microparticle suspensions. This study investigates suspension pH and nanoparticles–microparticles collision effects on the stabilization of an aqueous binary suspension. The long-term turbidity measurements show that for the nanosilica suspension stability is directly correlated with pH values; however, in the cases of zirconia and binary suspensions, it is not a monotonic function of pH. It is shown that for binary suspension, the halo mechanism is the primary method affecting the stability of the suspension. The suspension is best-stabilized at pH = 5 that is associated with high halo mechanism efficiency, while increased repulsive forces between micro and nanoparticles at pH = 8 result in halo mechanism decrease and so the stability reaches its minimum. On the other hand, a different trend is observed when the suspension includes only the silica microparticles, maximum stability is at pH = 8, that is related to the higher electrical repulsive forces between microparticles, and it is minimum at pH = 5, because of attractive Van der Waals forces dominancy. Furthermore, the results show that more collision between the nanoparticles and microparticles results in more adsorption of nanoparticles and hence more suspension stabilization at every pH values. This can be attributed to the increased collision between nanoparticles resulting in more nanoparticles be trapped in the profound potential well close to the microparticle surface, and so a stronger nanoparticle halo will form. Besides, it revealed that the effect of the collision on the stability of suspension is more significant at pH = 5.

Adsorption Behaviour of Ethylhydroxyethyl Cellulose on the Surface of Microparticles of Titanium and Ferrous Oxides

Adsorption Behaviour of Ethylhydroxyethyl Cellulose on the Surface of Microparticles of Titanium and Ferrous Oxides

Study of Microparticles Surface Modification by Electrokinetic Potential Measuring

Study of Microparticles Surface Modification by Electrokinetic Potential Measuring

Stable shape for copper film using low-temperature thermal decomposition of copper microparticles for printable electronics

A paste of copper microparticles, formic acid, and octylamine was developed to produce thick copper films with a stable shape and low electrical resistivity via low-temperature calcination. This study examined (1) the effect of cleaning the copper microparticle surface with formic acid, (2) the effect of calcination temperature, and (3) the effect that the addition of amine exerted on volume resistivity and on the shape of the copper film. The volume resistivities of the thick copper film were measured using a 4-point probe method. The thickness and shape of the copper film was observed via FE-SEM using an optical microscope.

Probiomimetics-Novel Lactobacillus-Mimicking Microparticles Show Anti-Inflammatory and Barrier-Protecting Effects in Gastrointestinal Models.

There is a lack of efficient therapies to treat increasingly prevalent autoimmune diseases, such as inflammatory bowel disease and celiac disease. Membrane vesicles (MVs) isolated from probiotic bacteria have shown tremendous potential for treating intestinal inflammatory diseases. However, possible dilution effects and rapid elimination in the gastrointestinal tract may impair their application. A cell-free and anti-inflammatory therapeutic system-probiomimetics-based on MVs of probiotic bacteria (Lactobacillus casei and Lactobacillus plantarum) coupled to the surface of microparticles is developed. The MVs are isolated and characterized for size and protein content. MV morphology is determined using cryoelectron microscopy and is reported for the first time in this study. MVs are nontoxic against macrophage-like dTHP-1 and enterocyte-like Caco-2 cell lines. Subsequently, the MVs are coupled onto the surface of microparticles according to facile aldehyde-group functionalization to obtain probiomimetics. A significant reduction in proinflammatory TNF-α level (by 86%) is observed with probiomimetics but not with native MVs. Moreover, it is demonstrated that probiomimetics have the ability to ameliorate inflammation-induced loss of intestinal barrier function, indicating their potential for further development into an anti-inflammatory formulation. These engineered simple probiomimetics that elicit striking anti-inflammatory effects are a key step toward therapeutic MV translation.

PAANa-induced ductile SEI of bare micro-sized FeS enables high sodium-ion storage performance

High-capacity metal chalcogenides often suffer from low initial coulombic efficiency (ICE) and serious capacity fading owing to the shuttle effect and volumetric expansion. Various carbon-coating and fixing methods were used to improve the above-mentioned performance. However, the synthesis processes of them are complex and time-consuming, limiting their engineering applications. Herein, polar polymer binder sodium polyacrylate (PAANa) is selected as an example to solve the problems of metal chalcogenides (bare micro-sized FeS) without any modification of the active materials. The special function of the polymer binder in the interface between the active material particles and the electrolytes demonstrates that a PAANa-induced network structure on the surface of ion sulfide microparticles not only buffers the mechanical stress of particles during discharging-charging, but also participates in forming a ductile solid electrolyte interphase (SEI) with high interfacial ion transportation and enhanced ICE. The cyclic stability and rate performance can be simultaneously improved. This work not only provides a new understanding of the binder on electrode, but also introduces a new way to improve the performance of batteries.

Assembly of chitosan-graphite oxide nanoplatelets core shell microparticles for advanced 3D scaffolds supporting neuronal networks growth

This manuscript reports the development of functional 3D scaffolds based on chitosan (CHI) and graphite oxide nanoplatelets (GO) for neuronal network growth. To this aim, CHI microparticles, produced by alkaline gelation method, were coated with GO exploiting a simple template-assisted assembly based on the electrostatic attraction in an aqueous medium. The optimal deposition conditions were evaluated by optical microscopy and studied by quartz crystal microbalance. FE-SEM observations highlight the formation of a core-shell structure where the porous chitosan core is completely wrapped by a uniform GO layer. This outer shell protects the inner chitosan from enzymatic degradation thus potentially extending the scaffold viability for in vivo applications. The presence of hydrophilic oxygen-containing functionalities on the outermost layer of GO and its inner conductive graphitic core maintained the bioactivity of the scaffold and promoted neuronal cell adhesion and growth. The proposed approach to modify the surface of CHI microparticles makes it possible for the design of 3D scaffolds for advanced neuronal tissue engineering applications.

The Interactions of Quantum Dot-Labeled Silk Fibroin Micro/Nanoparticles with Cells.

When silk fibroin particles are used for controlled drug delivery, particle size plays a key role in the location of the carrier on the cells as well as the transport pathway, utilization efficiency, and therapeutic effect of the drugs. In this study, the interactions of different-sized silk fibroin particles and cell lines were investigated. Silk fibroin microparticles with dry size of 1.9 ± 0.4 μm (2.7 ± 0.3 μm in wet state) and silk fibroin nanoparticles with dry size of 51.5 ± 11.0 nm (174.8 ± 12.5 nm in wet state) were prepared by salting-out method and high-voltage electrospray method, respectively. CdSe/ZnS quantum dots were coupled to the surface of the micro/nanoparticles. Photostability observations indicated that the fluorescence stability of the quantum dots was much higher than that of fluorescein isothiocyanate. In vitro, microparticles and nanoparticles were co-cultured with human umbilical vein endothelial cells EA.hy 926 and cervical cancer cells HeLa, respectively. The fluorescence test and cell viability showed that the EA.hy926 cells tended to be adhered to the microparticle surfaces and the cell proliferation was significantly promoted, while the nanoparticles were more likely to be internalized in HeLa cells and the cell proliferation was notably inhibited. Our findings might provide useful information concerning effective drug delivery that microparticles may be preferred if the drugs need to be delivered to normal cell surface, while nanoparticles may be preferred if the drugs need to be transmitted in tumor cells.

Analysis of the Nanoparticle Dispersion and Its Effect on the Crystalline Microstructure in Carbon-Additivated PA12 Feedstock Material for Laser Powder Bed Fusion.

Driven by the rapid development of additive manufacturing technologies and the trend towards mass customization, the development of new feedstock materials has become a key aspect. Additivation of the feedstock with nanoparticles is a possible route for tailoring the feedstock material to the printing process and to modify the properties of the printed parts. This study demonstrates the colloidal additivation of PA12 powder with laser-synthesized carbon nanoparticles at >95% yield, focusing on the dispersion of the nanoparticles on the polymer microparticle surface at nanoparticle loadings below 0.05 vol%. In addition to the descriptors “wt%” and “vol%”, the descriptor “surf%” is discussed for characterizing the quantity and quality of nanoparticle loading based on scanning electron microscopy. The functionalized powders are further characterized by confocal dark field scattering, differential scanning calorimetry, powder rheology measurements (avalanche angle and Hausner ratio), and regarding their processability in laser powder bed fusion (PBF-LB). We find that heterogeneous nucleation is induced even at a nanoparticle loading of just 0.005 vol%. Finally, analysis of the effect of low nanoparticle loadings on the final parts’ microstructure by polarization microscopy shows a nanoparticle loading-dependent change of the dimensions of the lamellar microstructures within the printed part.

Continuous in-line homogenization process for scale-up production of naltrexone-loaded PLGA microparticles

Injectable, long-acting drug delivery systems provide effective drug concentrations in the blood for up to 6 months. Naltrexone-loaded poly(lactide-co-glycolide) (PLGA) microparticles were prepared using an in-line homogenization method. It allows the transition from a laboratory scale to scale-up production. This research was designed to understand how the processing parameters affect the properties of the microparticles, such as microparticle size distributions, surface and internal morphologies, drug loadings, and drug release kinetics, and thus, to control them.The in-line homogenization system was used at high flow rates for the oil- and water-phases, e.g., 100 mL/min and 400 mL/min, respectively, to continuously generate microparticles. A high molecular weight (148 kDa) PLGA at various concentrations was used to generate oil-phases with a range of viscosities and also to compare with a 64 and 79 kDa at a single, high concentration. The uniformity of the microparticles was found to be related to the viscosity of the oil-phase. As the viscosity of the oil-phase increased from 52.6 mPa∙s to 4046 mPa∙s, the span value (a measure of uniformity) increased from 1.24 to 3.1 for the microparticles generated at the homogenization speed of 2000 RPM. Increasing the PLGA concentration from 5.58% to 16.85% showed a corresponding rise in the encapsulation efficiency from 74.0% to 85.8% and drug loading (DL) from 27.4% to 31.7% for the microparticles made with the homogenization speed of 2000 RPM. These increases may be due to a faster shell formulation, enabling PLGA microparticles to entrap more naltrexone into the structure. A higher DL, however, shortened the drug release duration from 56 to 42 days. The changes in morphology of the microparticles during different phases of the in vitro release study were also studied for three types of microparticles made with different PLGA concentrations and molecular weights. As PLGA microparticles went through structural changes, the surface showed raisin-like wrinkled morphologies within the first 10 days. Then, the microparticles swelled to form smooth surfaces. The in-line approach produced PLGA microparticles with a highly reproducible size distribution, DL, and naltrexone release rate.