Search Results (50)

With the depletion of river sand resources and increasing environmental concerns, the development of alternative materials has become an urgent need in the construction industry. Waste concrete and non-waste concrete materials have been widely studied as alternatives to river sand. Although recycled concrete fine aggregates are close to natural sand in terms of mechanical properties, their surface cement adheres and affects the performance of cement, whereas non-recycled concrete fine aggregates perform superiorly in terms of ease of use and compressive properties, but there are challenges of supply stability and standardization. Red mud, as an industrial waste, is a potential alternative material due to its stable supply and high alkaline characteristics. In this paper, a new method is proposed for utilizing the cross-linking reaction between sodium alginate and calcium chloride by the calcium alginate-red mud microsphere preparation technique and the surface modification of red mud to enhance its bonding with cement. The experimental results showed that the mechanical properties of CMC-RM-SiO₂-2.5% were improved by 13.9% compared with those of the benchmark cement mortar, and the encapsulation of red mud by calcium alginate significantly reduced the transfer of hazardous elements in red mud. Full article

Stem cells cultured in cell aggregates exhibit higher cell survival rates and enhanced anti-inflammatory and angiogenic effects compared to single cells, constructing a stable and economical cell aggregate culture system that can accurately adjust the mass transfer distance of nutrients, which contributes to improving the therapeutic effects of stem cell aggregates. In this study, an alginate hydrogel microsphere culture system (Alg-HM) was prepared using electrostatic spraying technology and refined by optimizing the electrostatic spraying technology parameters, such as the sodium alginate concentration, voltage, electrospray injection speed, and nozzle inner diameter. Furthermore, by setting the Tip-dropped culture system (Tip-D culture system, created by dropping the resuspended hMSC aggregate–hydrogel solution with a tip to form the hydrogel microsphere) and Matrigel culture system (created by dropping the resuspended hMSC aggregates–Matrigel solution with a tip to form the Matrigel culture system) as the control group and Alg-HM as the experimental group, the culture effect of hMSC aggregates in the optimized Alg-HM culture system was tested; CCK-8 detection and Ki-67 immunofluorescence staining showed that the Alg-HM culture system significantly enhanced the cell proliferation activity of hMSC aggregates after 7 and 14 days of culture. The Calcein-AM/PI cell staining results showed that the Alg-HM culture system can significantly reduce the central necrosis of hMSC aggregates. The RNA sequencing results showed that the Alg-HM culture system can significantly activate the signaling pathways related to cell proliferation in hMSCs. This culture system is helpful for the culture of cell aggregates in vitro and efficient transplantation in vivo. Full article

Ulcerative colitis (UC) is a chronic inflammation disease with severe impact on quality of life, with limited treatment options. Ramulus Mori alkaloids (SZ-A) from Morus alba show promise for UC treatment due to their safety and pharmacological effects, including anti-inflammation and barrier repair. However, their clinical use has been limited by gastrointestinal flatulence as a side effect due to their pharmacological action as an α-glucosidase inhibitor targeting the small intestine following oral administration. Therefore, constructing a colon-targeted formulation to deliver SZ-A is an advantageous strategy to improve UC therapy. In this study, we used the complex formed by thiolated hyaluronic acid, which has mucosal adhesion and inflammation-targeting properties, and SZ-A as an intermediate carrier and prepared sodium alginate-modified PLGA microspheres (SZ-A@MSs) with the double emulsion method to achieve efficient encapsulation of SZ-A. Specifically, sodium alginate serves as a gastric acid protectant and microbiota-responsive material, enabling the precise and responsive release of microspheres in the colonic region. SZ-A@MSs have a particle size of about 30 µm, a drug loading of about 12.0%, and an encapsulation efficiency of about 31.7% and function through intestinal adhesion to and targeting of inflammatory sites. SZ-A@MSs showed antioxidant and anti-inflammatory abilities in Raw264.7 cells. In vivo imaging results suggest that SZ-A@MSs have good colon site retention and sustained-release effect. Pharmacodynamic results show that SZ-A@MSs display good efficacy, including the ability to inhibit weight loss, inhibit colonic atrophy, and inhibit the secretion of inflammatory factors. In conclusion, SZ-A@MSs have good colon-targeting properties, can improve therapeutic effects, and provide a potential treatment method for UC. Full article

Sodium alginate is a polysaccharide compound extracted from natural plants that has been successfully prepared as a hydrogel for adsorbing and removing pollutants. However, the selectivity of alginate-based hydrogels to malachite green (MG) dyes and the stability of alginate-based hydrogels in air cannot meet requirements. Herein, metal–organic frameworks (MOFs) are embedded into a magnetic hydrogel to create magnetic MOF hydrogel (MMOF hydrogel) microspheres with high adsorption capacity. The morphology and physical properties of the MMOF hydrogel microspheres were characterized by scanning electron microscopy and optical microscopy. Under optimized adsorption conditions, the adsorption rate of MG reached 96.5%. The maximum adsorption capacity of the MMOF hydrogel for MG was determined to be 315 mg·g⁻¹. This highly efficient magnetic adsorbent for dye removal has considerable potential for rapidly removing toxic contaminants from aquatic food matrices for high-throughput sampling pretreatment, which has the potential for rapid, green, large-scale environmental remediation in the future. Full article

Microfluidic granulation technology enables high-quality production of energy-containing microspheres, significantly enhancing both performance and safety. Although microfluidic methods allow control over microsphere particle size, the adjustment range remains limited; low yield and process discontinuity also restrict broader application in the synthesis of energy-containing materials. This paper presents a microfluidic granulation system for energy-containing materials utilizing pulsed pneumatic printing, co-flow, and flow-focusing techniques to achieve wide particle size adjustment, consistent particle formation, high granulation speed, and production efficiency. This system allows microsphere sizes between 110 and 2500 μm, with a coefficient of variation (CV) as low as 1.9%, a frequency exceeding 13,000 Hz, and a suspension consumption rate reaching 100 mL/h. Calcium alginate/potassium perchlorate microspheres, prepared with sodium alginate hydrogel as a binder, exhibit uniform structure, narrow size distribution, and efficient energy material loading. We anticipate further advancements in applying microfluidic technology to energy-containing microsphere production based on this system. Full article

This work describes the immobilization and the characterization of purified Penicillium crustosum Thom P22 lipase (PCrL) using adsorption, encapsulation, and adsorption–encapsulation approaches. The maximum activity of the immobilized PCrL on CaCO₃ microspheres and sodium alginate beads was shifted from 37 to 45 °C, compared with that of the free enzyme. When sodium alginate was coupled with zeolite or chitosan, the immobilization yield reached 100% and the immobilized PCrL showed improved stability over a wide temperature range, retaining all of its initial activity after a one-hour incubation at 60 °C. The immobilization of PCrL significantly improves its catalytic performance in organic solvents, its pH tolerance value, and its thermal stability. Interestingly, 95% and almost 50% of PCrL’s initial activity was retained after 6 and 12 cycles, respectively. The characteristics of all PCrL forms were analyzed by X-ray diffraction and scanning electron microscopy combined with energy dispersive spectroscopy. The maximum conversion efficiency of oleic acid and methanol to methyl esters (biodiesel), by PCrL immobilized on CaCO₃, was 65% after a 12 h incubation at 40 °C, while free PCrL generated only 30% conversion, under the same conditions. Full article

Elevated brain iron levels are characteristic of many neurodegenerative diseases. As an iron chelator with short biological half-life, deferiprone leads to agranulocytosis and neutropenia with a prolonged therapeutic course. Its inclusion in sustained-release dosage forms may reduce the frequency of administration. On the other hand, when administered by an alternative route of administration, such as the nasal route, systemic exposure to deferiprone will be reduced, thereby reducing the occurrence of adverse effects. Direct nose-to-brain delivery has been raised as a non-invasive strategy to deliver drugs to the brain, bypassing the blood–brain barrier. The aim of the study was to develop and characterize nanocomposite microspheres suitable for intranasal administration by combining nano- and microparticle-based approaches. Nanoparticles with an average particle size of 213 ± 56 nm based on the biodegradable polymer poly-ε-caprolactone were developed using the solvent evaporation method. To ensure the deposition of the particles in the nasal cavity and avoid exhalation or deposition into the small airways, the nanoparticles were incorporated into composite structures of sodium alginate obtained by spray drying. Deferiprone demonstrated sustained release from the nanocomposite microspheres and high iron-chelating activity. Full article

Lead (Pb) and cadmium (Cd) are toxic pollutants that are prevalent in wastewater and pose a serious threat to the natural environment. In this study, a new immobilized bacterial microsphere (CYB-SA) was prepared from corn stalk biochar and Klebsiella grimontii by sodium alginate encapsulation and vacuum freeze-drying technology. The removal effect of CYB-SA on Pb(II) and Cd(II) in a monometallic contaminated solution was studied. The results showed that the removal of Pb(II) and Cd(II) by CYB-SA was 99.14% and 83.35% at a dosage of 2.0 g/L and pH = 7, respectively, which was 10.77% and 18.58% higher than that of biochar alone. According to the Langmuir isotherm model, the maximum adsorption capacities of Pb(II) and Cd(II) by CYB-SA at 40 °C were 278.69 mg/g and 71.75 mg/g, respectively. A combination of the kinetic model, the isothermal adsorption model, scanning electron microscopy–energy dispersive X-ray spectroscopy (SEM-EDS), X-ray photoelectron spectroscopy (XPS) and Fourier-transform infrared spectroscopy (FTIR) analyses showed that the main adsorption mechanisms of CYB-SA encompass functional group complexation, ion exchange, electrostatic attraction and physical adsorption. The findings of this study offer practical and theoretical insights into the development of highly efficient adsorbents for heavy metals. Full article

The development of functional foods is a viable alternative for the prevention of numerous diseases. However, the food industry faces significant challenges in producing functional foods based on probiotics due to their high sensitivity to various processing and gastrointestinal tract conditions. This study aimed to evaluate the effect of the operational conditions during the extrusion encapsulation process using vibrating technology on the viability of Lactobacillus fermentum K73, a lactic acid bacterium with hypocholesterolemia probiotic potential. An optimal experimental design approach was employed to produce sweet whey–sodium alginate (SW-SA) beads with high bacterial content and good morphological characteristics. In this study, the effects of frequency, voltage, and pumping rate were optimized for a 300 μm nozzle. The microspheres were characterized using RAMAN spectroscopy, scanning electron microscopy, and confocal laser scanning microscopy. The optimal conditions for bead production were found: 70 Hz, 250 V, and 20 mL/min with a final cell count of 8.43 Log₁₀ (CFU/mL). The mean particle diameter was 620 ± 5.3 µm, and the experimental encapsulation yield was 94.3 ± 0.8%. The INFOGEST model was used to evaluate the survival of probiotic beads under gastrointestinal tract conditions. Upon exposure to in vitro conditions of oral, gastric, and intestinal phases, the encapsulated viability of L. fermentum was 7.6 Log₁₀ (CFU/mL) using the optimal encapsulation parameters, which significantly improved the survival of probiotic bacteria during both the encapsulation process and under gastrointestinal conditions compared to free cells. Full article

Removing organic pollutants from wastewater is crucial to prevent environmental contamination and protect human health. Immobilized enzymes are increasingly being explored for wastewater treatment due to their specific catalytic activities, reusability, and stability under various environmental conditions. Peroxidases, such as horseradish peroxidase (HRP) and myoglobin (Mb), are promising candidates for immobilized enzymes utilized in wastewater treatment due to their ability to facilitate the oxidation process of a wide range of organic molecules. However, the properties of the carrier and support materials greatly influence the stability and activity of immobilized HRP and Mb. In this research, we developed immobilized HRP and Mb using support material composed of sodium alginate and CaCl₂ as carriers and glutaraldehyde as a crosslinking agent. Following this, the efficacy of immobilized HRP and Mb in removing aniline, phenol, and p-nitrophenol was assessed. Both immobilized enzymes removed all three organic pollutants from an aqueous solution, but Mb was more effective than HRP. After being immobilized, both enzymes became more resilient to changes in temperature and pH. Both immobilized enzymes retained their ability to eliminate organic pollutants through eight treatment cycles. Our study uncovered novel immobilized enzyme microspheres and demonstrated their successful application in wastewater treatment, paving the way for future research. Full article

In this study, a renewable and reusable immobilized Microcystis aeruginosa microsphere loaded with magnetic Nano-Fe₃O₄ composite adsorbent material is designed to study the treatment of wastewater containing heavy metal Sb(III). Through static absorption experiments combined with various characterization methods, this article studies the absorption process and mechanism of Sb(III), and investigates the optimal preparation conditions and environmental influencing factors. The results show that the optimal preparation conditions for immobilized Microcystis aeruginosa microspheres loaded with magnetic Nano-Fe₃O₄ adsorbent materials are 50.0% mass fraction of Microcystis suspension, 1.5% mass fraction of Nano-Fe₃O₄, and 2.5% mass fraction of sodium alginate. When the pH of the solution is 4, the reaction temperature is 25 °C, and the adsorbent dosage is 8.5 g/L, the removal rate of Sb(III) is the highest, reaching 83.62% within 120 min. The adsorption process conforms to the pseudo-second order kinetic model and Langmuir adsorption isotherm model, mainly characterized by chemical adsorption and surface complexation. Therefore, the composite material has been proven to be an efficient Sb (III) adsorption material. Full article

Biochar, a carbon-dense material known for its substantial specific surface area, remarkable porosity, diversity of functional groups, and cost-effective production, has garnered widespread acclaim as a premier adsorbent for the elimination of heavy metal ions and organic contaminants. Nevertheless, the application of powdered biochar is hindered by the challenges associated with its separation from aqueous solutions, and without appropriate management, it risks becoming hazardous waste. To facilitate its use as an immobilization medium, biochar necessitates modification. In this investigation, sodium alginate, celebrated for its superior gelation capabilities, was amalgamated with polyvinyl alcohol to bolster mechanical robustness, thereby embedding biochar to formulate sodium alginate biochar microspheres (PVA/SA-FMB). A meticulously designed response surface methodology experiment was employed to ascertain the optimal synthesis conditions for PVA/SA-FMB. Characterization outcomes unveiled a highly developed surface abundant in functional groups and confirmed the successful incorporation of iron ions. Adsorption trials revealed that at a temperature of 25 °C and a pH of 2, the adsorption capacity of PVA/SA-FMB for Cr(VI) was 13.7 mg/g within the initial 30 min, reaching an equilibrium capacity of 26.03 mg/g after 1440 min. Notably, the material sustained a Cr(VI) removal efficiency exceeding 90% across five cycles, underscoring its rapid and effective Cr(VI) eradication performance. Kinetic and isothermal adsorption analyses suggested that the adsorption of Cr(VI) adheres to a pseudo-second-order kinetic model and the Freundlich isotherm, indicative of monolayer adsorption dominated by reaction mechanisms. X-ray photoelectron spectroscopy (XPS) analysis inferred that the adsorption mechanism predominantly encompasses electrostatic attraction, redox processes, and complex formation. Full article

Three-dimensional (3D) hepatocyte models have become a research hotspot for evaluating drug metabolism and hepatotoxicity. Compared to two-dimensional (2D) cultures, 3D cultures are better at mimicking the morphology and microenvironment of hepatocytes in vivo. However, commonly used 3D culture techniques are not suitable for high-throughput drug screening (HTS) due to their high cost, complex handling, and inability to simulate cell–extracellular matrix (ECM) interactions. This article describes a method for rapid and reproducible 3D cell cultures with ECM–cell interactions based on 3D culture instrumentation to provide more efficient HTS. We developed a microsphere preparation based on a high-voltage electrostatic (HVE) field and used sodium alginate- and collagen-based hydrogels as scaffolds for 3D cultures of HepG2 cells. The microsphere-generating device enables the rapid and reproducible preparation of bioactive hydrogel microspheres. This 3D culture system exhibited better cell viability, heterogeneity, and drug-metabolizing activity than 2D and other 3D culture models, and the long-term culture characteristics of this system make it suitable for predicting long-term liver toxicity. This system improves the overall applicability of HepG2 spheroids in safety assessment studies, and this simple and controllable high-throughput-compatible method shows potential for use in drug toxicity screening assays and mechanistic studies. Full article

In this study, a capillary microfluidic device was constructed, and sodium alginate solution and a pH-sensitive hydrophobic polymer (p(BMA-co-DAMA-co-MMA)) solution were introduced into the device for the preparation of hydrogel fibers loaded with polymer microspheres. The structure of the microsphere fiber, including the size and spacing of the microspheres, could be controlled by flow rate, and the microspheres were able to degrade and release cargo responding to acidic pH conditions. By modification with carboxymethylcellulose (CMC), alginate hydrogel exhibited enhanced pH sensitivity (shrunk in acidic while swollen in basic condition). This led to an impact on the diffusion rate of the molecules released from the inner microspheres. The microsphere fiber showed dramatic and negligible degradation and drug release in tumor cell (i.e., A431 and A549 cells) and normal cell environments, respectively. These results indicated that the microsphere fiber prepared in this study showed selective drug release in acidic environments, such as tumor and inflammation sites, which could be applied as a smart surgical dressing with normal tissue protective properties. Full article

The aim of this study was to formulate and evaluate mucoadhesive sodium alginate microspheres for the nasal administration of Pentoxifylline to avoid first-pass metabolism. Microspheres were prepared using an ionic gelation process using a 2³-factorial design. We investigated the effects of several factors on particle size and in–vitro mucoadhesion, including the drug-to-polymer weight ratio, calcium chloride (CaCl₂) concentration, and cross-linking time. The particle size of the mucoadhesive microsphere was found in the 27.01 to 33.78 µm range, while the in vitro mucoadhesive result showed in the range 76.14 to 87.58%. The microspheres were characterized by SEM to study the shape and distribution of drugs within the microspheres. The surface morphology studied by SEM showed a spherical shape and the smooth surface of pentoxifylline-sodium alginate-loaded microspheres containing 2% w/v of Carbopol prepared by the ionotropic gelation method. The PM6 formulation shows highest percentage of in vitro diffusion (84.78%). In vitro dissolution tests were performed in a pH 6.2 phosphate buffer and indicated a non–Fickenian type of transport for the diffusion of drug from the Pentoxifylline mucoadhesive microsphere. It has been shown that the Hixson–Crowell model best describes the release of Pentoxifylline from Carbopol. The PM6 formulation utilized use of the Hixson–Crowell diffusion model of drug release, which was determined to be the model that best fit the data (r² = 0.9697). The formulation showed that the Fickian mechanism of drug release was acting when the n value was less than 0.5. Full article