Calcium Alginate Research Articles

Spherical Shell Bioprinting to Produce Uniform Spheroids with Controlled Sizes

Conventional cell spheroid production methods are largely manual, leading to variations in size and shape that compromise consistency and reliability for use in cell-based therapeutic applications. To enhance spheroid production, a spherical shell bioprinting system was implemented, enabling the high-throughput generation of uniform cell spheroids with precisely controlled sizes. The system encapsulates cells within thin alginate hydrogel shells formed through bioprinting and ion crosslinking reactions. Alginate–calcium ion crosslinking created alginate shells that contained gelatin-based bioinks with embedded cells, facilitating spontaneous cell aggregation within the shells and eliminating the need for plastic wells. By adjusting cell concentrations in the alginate–gelatin bioink, we achieved precise control over spheroid size, maintaining a sphericity above 0.94 and size deviations within ±10 µm. This method has been successfully applied to various cell types including cancer cells, fibroblasts, chondrocytes, and epithelial cells, demonstrating its versatility. This scalable approach enhances the reliability of cell therapy and drug screening, offering a robust platform for future biomedical applications.

A IMPORTÂNCIA DOS CURATIVOS ESPECIAIS EM FERIDAS DE DÍFICIL CICATRIZAÇÃO EM PACIENTES DE UMA CLÍNICA EM VITÓRIA DA CONQUISTA– BA

Wounds that are difficult to heal are those associated with diseases such as DM, SAH, leprosy, neoplasm, neurological and vascular problems, and others. Special dressings are suitable for the treatment of these injuries and, therefore, appropriate care is recommended. This research aims to: evaluate the relationship between the evolution of the healing process and the use of special dressings. This is a cross-sectional, quantitative and exploratory field research conducted in a clinic that specializes in wound prevention and treatment. The study included adults aged 60 to 70 years (50%), with lower limb injury (91.7%) over 1 year (58.3%), pathogenic history of Diabetes Mellitus and Systemic Arterial Hypertension (58.3%). %), adequate nutrition (91.7%), move independently (66.7%), diabetic foot and chronic wound (58.3%), deep wound involvement (83.3%), injured tissue granulated (75%), wounds with exudates and fibrosis (58.3%), moderate (50%) and mild (50%) pain, wound skin / edema (66.7%), macerated (91, 7%) and desquamative (66.7%). The lesions contain serous (41.7%), turbid (41.7%) and moderate (66.7%) exudates and characteristic odor (58.3%). The treatment is done with calcium alginate (66.7%), dressing up to 2 days (58.3%), with evolution in its entirety (100%). In view of the above, it is necessary to use these types of special covers to treat chronic injuries, but also the importance of comprehensive patient care, including the means of prevention, monitoring and treatment of existing co morbidities in order to obtain expected results.

Calcium Alginate Fibers/Boron Nitride Composite Lithium-Ion Battery Separators with Excellent Thermal Stability and Cycling Performance

As one of the most critical components in lithium-ion batteries (LIBs), commercial polyolefin separators suffer from drawbacks such as poor thermal stability and the inability to inhibit the growth of dendrites, which seriously threaten the safety of LIBs. In this study, we prepared calcium alginate fiber/boron nitride-compliant separators (CA@BN) through paper-making technology and the surface coating method using calcium alginate fiber and boron nitride. The CA@BN had favorable electrolyte wettability, flame retardancy, and thermal dimensional stability of the biomass fiber separator. Meanwhile, the boron nitride coating provided excellent thermal conductivity and mechanical strength for the composite separator, which inhibited the growth of lithium dendrites and enabled lithium-ion symmetric batteries to achieve more than 1000 stable and long cycles at a current density of 0.5 mA cm−2. The interwoven fiber mesh formed by the boron nitride coating and the calcium alginate provided multiple pathways for ion migration, which enhanced the storage capacity of the electrolyte, improved the interfacial compatibility between the separator and the electrode, widened the window of electrochemical stability, and enhanced ionic migration. This eco-friendly bio-based separator paves a new insight for the design of heat-resistance separators as well as the safe running of LIBs.

Theoretical and experimental study on efficient thorium removal from aquatic environment using phosphate-modified graphene oxide polymeric beads

AbstractThorium is an element of immense importance in nuclear industry due to lower environmental impact compared to fossil fuels and conventional nuclear power. In the present study, highly selective adsorption of Th4+ on phosphate modified graphene oxide polymeric beads was investigated. The interaction of –PO4, –OH and –O– functional groups of graphene oxide with thorium ion was thoroughly investigated using Density Functional Theory. The adsorption induced density difference was utilized to investigate the bonding characteristics. The affinity of the Th4+ ions was obtained as –PO4 > –OH > –O– group of the phosphate modified graphene oxide. Phosphate modified Graphene oxide embedded in Calcium alginate matrix was characterized using ATR-FTIR, XRD, SEM and Raman spectroscopy. Highly efficient (> 93%) uptake of thorium at pH 5 with fast rate of sorption (< 5 min) was observed in the batch sorption studies.

Improvement of Adsorption Capacity by Refined Encapsulating Method of Activated Carbon into the Hollow-Type Spherical Bacterial Cellulose Gels for Oral Absorbent

To reduce the risk of adsorption of granular activated carbon (AC) in the gastrointestinal tract, we successfully prepared a hollow-type spherical bacterial cellulose gel encapsulated with AC (ACEG) and evaluated its pH tolerance and adsorption capacity. The bacterial cellulose gel membrane of ACEG features a three-dimensional mesh structure of cellulose fibers, allowing the selective permeation of substances based on their size. In this study, the preparation method of ACEGs was investigated, and the indole saturation adsorption capacity of the obtained gel was measured. We modified the gel culture nucleus gel from calcium alginate gel to agar gel, facilitating the encapsulation of previously challenging particles. The new preparation method used sodium hydroxide solution for sterilization and dissolution to remove the debris of Komagataeibacter xylinus, which was feared to remain in the bacterial cellulose membrane. This treatment was also confirmed to have no effect on the adsorption capacity of the AC powder. Therefore, this new preparation method is expected not only to improve the performance of ACEGs but also to be applied to a wide range of adsorbent-encapsulated hollow-type bacterial cellulose gels.

Endomelanconiopsis endophytica Lipase Immobilized in Calcium Alginate for Production of Biodiesel from Waste Cooking Oil

The increasing global demand for biodiesel is due to the urgent need to replace fossil diesel with a fuel based on renewable energy sources. Although chemical catalysis is widely used to produce biodiesel, it uses harsh operating conditions, has high energy consumption, and generates unwanted byproducts. In this scenario, biocatalysis stands out as an efficient and environmentally friendly alternative to chemical catalysis. In biocatalysis, the use of immobilized enzymes plays an important role in the reduction in costs. In this sense, we investigated the use of the lipase produced by an Amazonian endophytic fungus in an immobilized form in the transesterification of waste cooking oil for biodiesel production. The fungus Endomelanconiopsis endophytica QAT_7AC demonstrated a high production of lipase. The lipolytic extract was precipitated in ethanol, which increased the specific enzyme activity. The lipolytic extract and the precipitated lipolytic extract were immobilized in calcium alginate beads. Immobilization efficiency was over 89%. The immobilized biocatalysts showed thermal stability and were used in the production of biodiesel using waste cooking oil and ethanol. It was possible to reuse them for up to four reaction cycles, with yields greater than 70%. These results prove the efficiency of immobilized biocatalysts in the production of biodiesel from waste oils.

A Programmable Oral Nanomotor Microcapsule for the Treatment of Inflammatory Bowel Disease

AbstractGiven the unique anatomy and location of inflammatory bowel disease (IBD), oral pharmacological treatment is the mainstay for managing IBD because of its convenience and direct accessibility to the gastrointestinal tract. However, efficient delivery systems must be designed to navigate the harsh gastrointestinal environment during application. Here, an innovative oral drug delivery system was proposed using nanomotor (NM)‐loaded soluble microcapsules for treating IBD. MnO2‐Au‐mSiO2 NMs incorporate partially encapsulated MnO2 antennas that convert reactive oxygen species into oxygen, autonomously propelling the NMs. Astaxanthin (AST), known for its anti‐inflammatory properties, is loaded into the mesoporous silica (mSiO2) of NMs (AST@NMs). AST effectively reduces inflammation and shifts macrophages from a proinflammatory (M1) phenotype to an anti‐inflammatory (M2) phenotype. To protect the nanomotors from harsh digestive conditions and achieve intestinal‐responsive release, using photocurable 3D printing, we fabricated enteric‐coated oral microcapsules (MCs). Additionally, to prevent leakage of AST@NMs, a calcium alginate shell was cured in situ on the surface of the microcapsules (AST@NMs@MCs). In vitro and in vivo, AST@NMs@MCs effectively reduced inflammation, repaired the intestinal barrier, and modulated the gut microbiota. These findings underscore the protective effects of the microcapsules on AST@NM, highlighting their potential as a promising strategy for treating colitis.

Enhanced catalytic efficiency and ionic liquid tolerance of entrapped cellulase for single-step mixed cabbage residue saccharification

This study explores the enhancement of catalytic efficiency and 1-ethyl-3-methylimidazolium acetate ([Emim][OAc]) tolerance in the single-step saccharification of mixed cabbage residue (MCR) biomass using entrapped cellulase. Entrapping cellulase in calcium alginate hydrogel beads achieved an entrapment efficiency of 75.90 ± 1.83 %. In hydrolysis systems with 2 % and 10 % [Emim][OAc], the entrapped cellulase demonstrated 5.3 % and 6.5 % higher activity than free cellulase, respectively. After five cycles, the entrapped cellulase retained 93 % and 87 % of its initial activity in 0 % and 2 % [Emim][OAc] hydrolysis systems, respectively. Remarkably, cumulative glucose yields with entrapped cellulase were 3.51 and 3.10 times greater than those with free cellulase in 0 % and 2 % [Emim][OAc] hydrolysis systems, respectively. These results highlight the superior performance of entrapped cellulase in maintaining enzyme activity and improving glucose yields. Notably, while [Emim][OAc] is effective in separate pretreatment stages, its addition is unnecessary for the single-step saccharification of MCR biomass. This study underscores the promising potential of entrapped cellulase as a catalyst in enhancing the efficiency of biomass saccharification processes.

Mechanically robust MOF beads for efficient ethylene/ethane separation with fast adsorption kinetics

Shaping of metal–organic frameworks (MOFs) without obvious mass transfer resistance is crucial for scaled-up adsorption separation process. Herein, mechanically robust ultramicroporous MOF (ZU-901, also termed CPL-1-CH3) beads with hierarchical porosity were structured through the calcium alginate (CA) method, which preserved the adsorption separation performance and demonstrated fast gas diffusion rates. The highly crosslinked networks of CA contributed to the excellent mechanical properties of 95 % ZU-901@CA beads with Young’s modulus up to 1.81 MPa and a low abrasion rate of 0.32 %, superior to that of 95 % ZU-901@HPC extrudates (1.13 %). Compared with powder of ZU-901, the C2H4 uptake capacity of ZU-901@CA beads showed only 3 % loss at 298 K. The C2H4 diffusion time constant of 95 % ZU-901@CA beads (7.06 × 10−3 s−1) was comparable to that of the powders (7.61 × 10−3 s−1) and higher than that of ZU-901@HPC extrudates (2.95 × 10−3 s−1). Breakthrough experiments confirmed that ZU-901@CA beads performed well in the dynamic separation of C2H4/C2H6 binary mixture, and could be easily regenerated at room temperature. In addition, after post modification on the exterior of ZU-901 beads, the water contact angle increased from 0° to 119°. Therefore, the mechanically robust ZU-901@CA beads showed great potential in energy-efficient C2H4/C2H6 separation.

Antifungal peptide-loaded alginate microfiber wound dressing evaluated against Candida albicans in vitro and ex vivo

Invasive fungal infections have high mortality rates, and many current antimycotics are limited by host toxicity and drug resistance. Recent experiments in our laboratory have demonstrated the antifungal activity of dKn2-7, a synthetic peptide, against Candida albicans. The purpose of the current study was to develop a wound dressing capable of dKn2-7 release for extended periods to help combat fungal infection in wounds. dKn2-7 was incorporated into calcium alginate microfibers, an excipient with known wound healing and hemostatic properties. dKn2-7 release rates from the fibers were dependent on drug loading, but all formulations exhibited a burst release with 41–71 % of total release in the first 15 min and 84–96 % release by 24 h. Calcium release at 15 min was similar to that of a commercial hemostatic dressing, indicating dKn2-7 loading would not adversely affect the hemostatic capability of the alginate fibers. In vitro antifungal studies indicated a dose dependent effect with fibers loaded at ≥20 µg/mg causing significant planktonic killing and ≥30 µg/mg causing significant biofilm killing. Viable fungal counts in biofilms grown on ex vivo porcine skin declined by 99 % following 500 µg/mg fiber treatment. Skin histology indicated no significant differences in tissue damage between treatment groups and controls. Results confirm calcium alginate microfibers are capable of binding and subsequently releasing dKn2-7 over a 24-h period when rehydrated. Furthermore, dKn2-7 released from the fibers was able to significantly reduce biofilms in an ex vivo model with minimal toxicity, indicating these dKn2-7 loaded fiber dressings may be effective at controlling C. albicans biofilm infections in vivo.

Degree of sulfation of freeze-dried calcium alginate sulfate scaffolds dramatically influence healing rate of full-thickness diabetic wounds.

Diabetic foot ulcer (DFU) is a chronic and non-healing wound in all age categories with a high prevalence and mortality in the world. An ideal wound dressing for DFU should possess the ability of adsorbing high contents of exudate and actively promote wound healing. Here, we introduced the calcium alginate sulfate as a new biomaterial appropriate for use in wound dressing to promote the healing of full-thickness ulcers in a diabetic mouse model. In this regard, alginate sulfate (Alg-S) solutions with different degree of substitution (DS) of 0.2, 0.5, and 0.9 were synthesized, freeze-dried, crosslinked by calcium cations, purified by washing and refreeze-dried. Primary analyses including swelling ratio, porosity content and mechanical properties revealed that all Alg-S scaffolds possess necessities for use as a wound dressing. After confirming the cytocompatibility of both alginate and alginate sulfate-based scaffolds by MTT assay, they were used as wound dressing for healing of full-thickness ulcers in diabetic mice. The results of wound healing process confirmed that calcium alginate sulfate scaffolds can heal the wounds faster than both alginate-treated and non-treated wounds. Furthermore, the histological analyses of healed tissues reveled normal regeneration of the skin tissue layers and collagen deposition similar to the healthy tissue.

Calcium alginate-encapsulated propolis microcapsules: Optimization, characterization, and preservation effects on postharvest sweet cherry

The increasing consumption of fresh fruits and vegetables has led to the development of eco-friendly and active preservation materials which have slow-release effect of antioxidant/antifungal agents. The propolis microcapsules (PM), utilizing calcium alginate as the wall material, incorporating ethanolic extract of propolis (EEP) as the core material, were prepared by ionic gelation method and conducted a investigation of its characteristics After optimization by single factor experiment and theoretical response models, PM which was prepared by dropping 9.3 g L−1 100 mL sodium alginate solution containing 9.8 mL EEP into 0.22 mol L−1 calcium chloride solution showed an encapsulation efficiency of 69.29±1.12 %. Prepared microcapsules were spherical with a dense surface which protected propolis well from the environment, retained a large number of bio-active compounds and improve thermal stability of propolis. Moreover, the microcapsules exhibited good slow-release effect and good inhibitory influence on the development of Alternaria Alternata growth which the colony diameter of the control was 41.38 % higher than the treatment at day six. With 5.0 g PM placed in the small non-woven bag in the application on sweet cherries with non-direct contact method, the decay rate and weight loss of fruits were reduced by 47.5 % and 17.6 %, concurrently the PM also effectively maintain the good appearance, hardness, antioxidant capacity by slowing the reduction in the content of total phenols, flavonoids and enzymatic activities. Therefore, the PM with superior antioxidant and antifungal capacity have the great potential to design as a practical active materials for fruits preservation.

Sensitivity-enhanced optical fiber probe-type humidity sensor based on CaAlg film

Optical fiber probe-type humidity sensors based on calcium alginate (CaAlg) hydrogel films are proposed. The sensor is based on the Michelson interferometer (MI) and constructed by splicing a tapered multimode fiber (MMF) in the middle of two single-mode fibers (SMFs). One of the 1.5 cm long SMFs is coated with CaAlg hydrogel film and can be regarded as the sensor probe. The sensitivity of the sensor is 0.31015 nm/%RH. The high sensitivity, low temperature crosstalk, compact probe structure, and stability of the sensor allow it to be used for humidity monitoring in a variety of complex environments.

Calcium alginate/Polyaniline double network aerogel electrode for compressible and high electrochemical performance integrated supercapacitors

As a new type of energy storage device, supercapacitors have attracted more and more attention due to their excellent performance. However, the current electrode materials have limited specific surface area and cannot meet the needs of high energy storage. The aerogel material is a 3D network structure containing interconnected micro-nano structures, and also has hierarchical pores on the micro, meso and macro scales. The microporous and mesoporous structures can provide high specific surface area, while the macropores provide channels for the entry of active substances. In this study, calcium alginate (CA)/polyaniline (PANI)/reduced graphene oxide (RGO) aerogels based on double network structure with high mechanical property and excellent electrochemical performance are successfully constructed by sol-gel method. Due to the double network structure, the CA/PANI/RGO aerogel exhibits self-supported 3D porous network structures with high surface areas (330.3 m2/g). CA/PANI/RGO composite aerogel electrode shows high specific capacitance (908 F/g at 1 A/g) and excellent rate performance. The initial capacitance of more than 80 % can be maintained after 10,000 times of charge/discharge cycle test. Most importantly, the assembled flexible solid-state supercapacitor has high specific capacitance (885 F/g at 1 A/g) and mechanical flexibility (92.6 % of the capacitance retention after 1000 bending cycles).

Durable fluorinated cobalt oxyhydroxide/calcium alginate hydrogels for activating peroxymonosulfate to enable nearly 100% degradation of ciprofloxacin.

Peroxymonosulfate (PMS) activation by solid catalysts for ciprofloxacin (CIP) removal is a promising method for decontaminating wastewater. However, mainstream catalysts suffer from efficiency and durability issues due to mechanical fragility and structural instability. Here, we have developed a durable calcium alginate hydrogel encapsulating fluorinated cobalt oxyhydroxide (FCO/CAH), fabricated by a simple hydrogen-bond-assisted cross-linking reaction, to enhance PMS activation for complete CIP removal. The optimized 2-FCO/CAH could generate abundant singlet oxygen (1O2) and sulfate radicals (SO4˙-) with PMS, resulting in 0.433 min-1 kinetic constant and approximately 100% CIP degradation within 10 minutes. This exceptional degradation efficiency is due to the even distribution of 2-FCO, which maximizes catalytic sites for PMS activation, and the multichannel cavity structure of CAH, which effectively enriches both PMS and CIP. Furthermore, the durability of 2-FCO/CAH was proved by its negligible decay in CIP removal efficiency (∼100%) and good microstructure retention after 6 consecutive cycles, facilitated by a stable surface reconstructed interphase on the 2-FCO surface and the strong mechanical property of 2-FCO/CAH. Our work showcases a facile approach to constructing durable hydrogel catalysts that improve PMS-mediated antibiotic degradation.

Regulation of Adsorption Properties of Whey Protein Isolate Fibril-Calcium Alginate Aerogels by Controlling Protein Fibrillation Time.

Amyloid-like fibrils have a relatively high specific surface area, which makes them suitable as absorbents. In this study, we prepared absorbent composite aerogels from whey protein isolate fibril (WPIF) and calcium alginate (CA). The impact of protein fibrillation time (4-24 h) on the adsorption properties of these aerogels was assessed, as this influences the nature of the WPIFs formed. Fourier transform infrared spectroscopy analysis indicated that hydrogen bonding, hydrophobic interactions, and electrostatic interactions were the main molecular interactions in the composite aerogels. Then, the adsorption properties of the aerogels were investigated using crystal violet as a model compound. The adsorption properties of all composite aerogels were significantly improved compared to CA aerogels, which was mainly attributed to the numerous functional groups of the surfaces of the WPIFs, as well as the rougher surface topology of the composite aerogels. The adsorption capacity of the composite aerogels first increased and then decreased with increasing fibrillation time, with 8 h fibrillation leading to the largest adsorption capacity (1886.11 mg/g). Thioflavin T fluorescence, atomic force microscopy, light extinction, average particle size, and zeta potential analysis indicated that the high fibril content, mature fibril morphology, large number of available functional groups on the surface, and relatively low zeta potential of WPIF8 might be the main reasons. Adsorption kinetics and isothermal adsorption profile analysis suggested that monolayer adsorption occurred through chemical adsorption processes. The edible aerogel with high adsorption properties developed in this work has potential application in food and biomedical fields.

Carbon Ink Enhanced Calcium Alginate-Based Hydrogel with Response Surface Methodology Optimized for Solar-Driven Salt-Tolerant Desalination.

The global shortage of freshwater resources is becoming more and more serious; therefore, it is necessary to obtain freshwater by desalinating seawater resources. Solar-driven interfacial photothermal evaporation, which is an environmentally friendly and energy-efficient technology, has been used to desalinate seawater for water purification and production. Herein, the IPCA hydrogel with abundant pores consisting of carbon ink as a photothermal conversion material and PU sponge loaded with calcium alginate as a water transport medium was successfully prepared and used to obtain portable water. The parameters of the synthesized IPCA are optimized by Response Surface Methodology analysis, and it was found that the IPCA exhibits a high evaporation efficiency of 3.779 kg m-2 h-1 and up to 95.98% of photothermal conversion capacity under one solar intensity. It maintains a high evaporation efficiency and salt resistance after 10 cycles of evaporation in actual seawater. Moreover, IPCA shows a high removal of various organic dye pollutants in wastewater. The results suggest a new approach for the preparation of simple, efficient, and green solar evaporators in practical application.

Integration of cadmium sulfide quantum dots with calcium alginate microbeads for dual-functional mercury (II) ion sensing and removal

Mercury contamination poses human health as well as ecosystem at significant risks. This study introduces a novel approach for the selective detection with removal of Hg2+ ions from aqueous media by developing a dual functional adsorbent that combines calcium alginate microbeads (FMCAB) with capped cadmium sulfide quantum dots (CdS QDs). CdS QDs immobilized on calcium alginate microbeads in magnetite facilitated efficient separation from the adsorption system under an external magnetic field. The fluorescence properties of CdS QDs remain largely unaffected before and after adsorption of Hg2+ ions on FMCAB, enabling selective monitoring of these ions. The adsorbent demonstrated a high adsorption capacity of around 160 μg/g and exhibited a quick and effective process. FMCAB evidenced selectivity over the other metal ions with limits of detection 12.9 μM. The results from this research pave the way for novel applications of FMCAB for heavy metal ions sensing probes and its removal.

Extraction, Characterization, and Encapsulation of Cinnamon Hydrosol Obtained via Microwave-Assisted Hydrodistillation: Analysis of Antioxidant and Antimicrobial Activities

Microwave-assisted hydrodistillation (MAHD) method was employed to extract cinnamon oil and hydrosol (a byproduct). The total polyphenol content (TPC) of the cinnamon hydrosol (CH) was determined using the Folin-Ciocalteu method, and its antioxidant power was assessed through the DPPH radical reduction method. Gas chromatography was utilized to quantify the main bioactive compound (cinnamaldehyde). The disc agar diffusion method was applied to evaluate the inhibition of pathogenic microorganisms. To protect the bioactive compound, an encapsulation method involving cross-linking with calcium alginate was utilized. The capsules were examined using environmental scanning electron microscopy (ESEM). The TPC content was found to be 15.63 ± 0.21 mg gallic acid/g dry matter, and the DPPH radical inhibition rate was 84.26 ± 1.35%. CH exhibited a significant inhibitory effect against Escherichia coli, and a moderate inhibition effect against Shigella flexneri, Salmonella spp., Salmonella typhimurium, and Escherichia coli EPEC. Finally, successful encapsulation of CH was achieved using sodium alginate, resulting in bead sizes ranging between 1.75 and 2.75 mm.

Investigating the Feasibility of Xylitol and Gelatin for Controlled Release System in Drug Delivery using Calcium Alginate

Investigating the Feasibility of Xylitol and Gelatin for Controlled Release System in Drug Delivery using Calcium Alginate