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This study presents a novel biosorbent developed by immobilizing dead Sp2b bacterial biomass into calcium alginate (CASp2b) to efficiently remove arsenic (As III ) from contaminated water. The bacterium Sp2b was isolated from arsenic-contaminated industrial soil of Punjab, a state in India. The strain was designated Acinetobacter sp. strain Sp2b as per the 16S rDNA sequencing, GenBank accession number -OP010048.The CASp2b was used for the biosorption studies after an initial screening for the biosorption capacity of Sp2b biomass with immobilized biomass in both live and dead states. The optimum biosorption conditions were examined in batch experimentations with contact time, pH, biomass, temperature, and As III concentration variables. The maximum biosorption capacity (q max  = 20.1 ± 0.76 mg/g of CA Sp2b) was obtained at pH9, 35 ̊ C, 20 min contact time, and 120 rpm agitation speed. The isotherm, kinetic and thermodynamic modeling of the experimental data favored Freundlich isotherm (R 2  = 0.941) and pseudo-2nd-order kinetics (R 2  = 0.968) with endothermic nature (ΔH° = 27.42) and high randomness (ΔS° = 58.1).The scanning electron microscopy with energy dispersive X-ray (SEM–EDX) analysis indicated the As surface binding. The reusability study revealed the reasonable usage of beads up to 5 cycles. In conclusion, CASp2b is a promising, efficient, eco-friendly biosorbent for As III removal from contaminated water.

Natural Killer (NK) cells participate in the defense against infection by killing pathogens and infected cells and secreting immuno-modulatory cytokines. Defects in NK cell activity have been reported in obese, diabetic, and elderly patients that are at high risk of developing infected chronic wounds. Calcium alginate dressings are indicated for the debridement during the inflammatory phase of healing. Since calcium ions are major activators of NK cells, we hypothesized that these dressings could enhance NK functions, as investigated in vitro herein. Primary human blood NK cells were freshly-isolated from healthy volunteers and exposed to conditioned media (CM) from two alginate dressings, Algosteril ® (ALG, pure Ca 2+ alginate) and Biatain ® Alginate (BIA, Ca 2+ alginate with CMC), in comparison with an exogenous 3mM calcium solution. Our results demonstrated that exogenous calcium and ALG-CM, but not BIA-CM, induced NK cell activation and enhanced their capacity to kill their targets as a result of increased degranulation. NK cell stimulation by ALG depended on the influx of extracellular Ca 2+ via the SOCE Ca 2+ permeable plasma membrane channels. ALG-CM also activated NK cell cytokine production of IFN-γ and TNF-α through a partly Ca 2+ -independent mechanism. This work highlights the non-equivalence between alginate dressings for NK cell stimulation and shows that the pure calcium alginate dressing Algosteril ® enhances NK cell cytotoxic and immuno-modulatory activities. Altogether, these results underline a specific property of this medical device in innate defense that is key for the cutaneous wound healing process.

Diabetic foot problems pose a substantial global health challenge as a major complication of diabetes mellitus. These issues encompass a spectrum of conditions affecting the feet of individuals with diabetes, including neuropathy (nerve damage), peripheral artery disease (impaired blood circulation), foot ulcers, infections, and, in critical situations, amputation. To mitigate the burden of lower extremity amputations, the development of innovative wound dressings and drug delivery systems is crucial. One such advancement is the “lyophilized wafer formulation,” a recently developed medicated dressing material known for its rapid healing properties and high exudate absorption capacity in chronic wounds. Following successful completion of assessment tests for lymphatic fluid retention, viscosity, in vitro drug release, FTIR, DSC, and XRD, the exudate absorption capacity of calcium alginate was evaluated in the current study. Notably, the wafer formulation composed of 2% calcium alginate, 1% gelatin (bloom 150), and water as the solvent demonstrated excellent performance across exudate management properties, as well as in FTIR, DSC, XRD, and in vitro drug release assays using a dialysis membrane. This optimal formulation achieved a significant drug release of 96.9 ± 0.1% after 24 h. The Linezolid-loaded calcium alginate wafer formulation exhibited promising outcomes concerning antimicrobial properties, exudate handling, and drug release. Furthermore, the animal study indicated the absence of adverse effects, underscoring the formulation’s potential as a safe and effective treatment for diabetic foot ulcers without inducing skin irritation. To fully realize its therapeutic value, comprehensive investigations into its stability profile and detailed pharmacological effects are strongly recommended.

This study developed a drug-loadable hydrogel system with high plasticity and favorable biological properties to enhance oral bone tissue regeneration. Hydrogels of different calcium alginate concentrations were prepared. Their swelling ratio, degradation time, and bovine serum albumin (BSA) release rate were measured. Human periodontal ligament cells (hPDLCs) and bone marrow stromal cells (BMSCs) were cultured with both calcium alginate hydrogels and polylactic acid (PLA), and then we examined the proliferation of cells. Inflammatory-related factor gene expressions of hPDLCs and osteogenesis-related gene expressions of BMSCs were observed. Materials were implanted into the subcutaneous tissue of rabbits to determine the biosecurity properties of the materials. The materials were also implanted in mandibular bone defects and then scanned using micro-CT. The calcium alginate hydrogels caused less inflammation than the PLA. The number of mineralized nodules and the expression of osteoblast-related genes were significantly higher in the hydrogel group compared with the control group. When the materials were implanted in subcutaneous tissue, materials showed favorable biocompatibility. The calcium alginate hydrogels had superior osteoinductive bone ability to the PLA. The drug-loadable calcium alginate hydrogel system is a potential bone defect reparation material for clinical dental application.

Owing to bio-polymer’s low-cost, environmental friendliness and mechanically stable nature, calcium alginate microcapsules have attracted much interest for their applications in numerous fields. Among the common production methods, the Electrospraying technique has shown a great potential due to smaller shape capsule production and ease of control of independent affecting parameters. Although one factor at a time (OFAT) can predict the trends of parameter effect on size and sphericity, it is inefficient in explaining the complex parameter interaction of the electrospray process. In the current study, the effects of the main parameters affecting on size and sphericity of the microcapsules using OFAT were optimized to attain calcium alginate microcapsules with an average diameter below 100 µm. Furthermore, we propose a statistical model employing the Surface Responses Methodology (RSM) and Central Composite Design (CDD) to generate a quadratic order linear regression model for the microcapsule diameter and sphericity coefficient. Experimentally, microcapsules with a size of 92.586 µm and sphericity coefficient of 0.771 were predicted and obtained from an alginate concentration of 2.013 w/v, with a flowrate of 0.560 mL/h, a needle size of 27 G and a 2.024 w/v calcium chloride concentration as optimum parameters. The optimization processes were successfully aligned towards formation of the spherical microcapsules with smaller average diameter of less than 100 µm, owing to the applied high voltage that reached up to 21 kV.

After decades of research, fully functional skin regeneration is still a challenge. Skin is a multilayered complex organ exhibiting a cascading healing process affected by various mechanisms. Specifically, nutrients, oxygen, and biochemical signals can lead to specific cell behavior, ultimately conducive to the formation of high-quality tissue. This biomolecular exchange can be tuned through scaffold engineering, one of the leading fields in skin substitutes and equivalents. The principal objective of this investigation was the design, fabrication, and evaluation of a new class of three-dimensional fibrous scaffolds consisting of poly(ε-caprolactone) (PCL)/calcium alginate (CA), with the goal to induce keratinocyte differentiation through the action of calcium leaching. Scaffolds fabricated by electrospinning using a PCL/sodium alginate solution were treated by immersion in a calcium chloride solution to replace alginate-linked sodium ions by calcium ions. This treatment not only provided ion replacement, but also induced fiber crosslinking. The scaffold morphology was examined by scanning electron microscopy and systematically assessed by measurements of the pore size and the diameter, alignment, and crosslinking of the fibers. The hydrophilicity of the scaffolds was quantified by contact angle measurements and was correlated to the augmentation of cell attachment in the presence of CA. The in vitro performance of the scaffolds was investigated by seeding and staining fibroblasts and keratinocytes and using differentiation markers to detect the evolution of basal, spinous, and granular keratinocytes. The results of this study illuminate the potential of the PCL/CA scaffolds for tissue engineering and suggest that calcium leaching out from the scaffolds might have contributed to the development of a desirable biological environment for the attachment, proliferation, and differentiation of the main skin cells (i.e., fibroblasts and keratinocytes).

The calcium alginate/Fe3O4 capsules with multi-chamber structure can release interior rejuvenator under cyclic load and microwave irradiation; however, the rejuvenator release mechanism of capsules under two types of external activation is still unknown. Hence, this paper investigates the rejuvenator release mechanism of capsules in asphalt concrete under cyclic load and microwave irradiation. This research covers the synthesis of calcium alginate/Fe3O4 capsules and the evaluation of fundamental characteristics. The asphalt concrete containing capsules are subjected to cyclic load and microwave irradiation, respectively. The rejuvenator discharge ratio of capsules after external activation is determined using FTIR spectrum analysis. Furthermore, the structure characteristics of the extracted capsules are monitored after cyclic load and microwave irradiation. The findings indicate that the capsules present a sustained release feature under cyclic load. The outer capsule surfaces forms microcracks (diffusion channel) and inner chamber walls generate micropores (release channel) under cyclic load pressure. The capsules release inner rejuvenator rapidly under the microwave irradiation. The nano-Fe3O4 particles generate irregular movement and form microwave action spots under the action of microwave irradiation, and the micropores (release and diffusion channel) occur on the outer surface of capsules and inner chamber wall. This paper reveals the mechanism of long-lasting slow release under cyclic load and active release under microwave irradiation of dual-responsive capsules, which may provide a theoretical basis for the all-season service of the capsule and the long-term intelligent maintenance of asphalt pavement.

Calcium alginate capsules within asphalt concrete can gradually release interior asphalt rejuvenator under cyclic loading to repair micro cracks and rejuvenate aged asphalt in-situ. However, asphalt pavement will become aged due to environmental and traffic factors during the service period. In view of this, this paper investigated the effect of ageing on the healing properties of asphalt concrete containing calcium alginate/attapulgite composite capsules under cyclic loading. The capsules were fabricated using the orifice-bath method and the morphological structure, mechanical strength, thermal stability, oil release ratios and healing levels of capsules in fresh, short-term ageing and long-term ageing asphalt concrete were explored. The results indicated that the different ageing treatments would not damage the multi-chamber structure nor decrease the mechanical strength of capsules but would induce the capsules release oil prematurely. The premature oil released from capsules in turn can offset the ageing effect owing to ageing treatment. The short-term ageing and long-term ageing plain asphalt mixtures gained strength recovery ratios of 39.3% and 34.2% after 64,000 cycles of compression loading, while the strength recovery ratios of short-term ageing and long-term ageing asphalt mixtures containing capsules were 63.5% and 54.8%, respectively.

Cold Mix Asphalt (CMA) is a sustainable alternative to conventional hot mix asphalt (HMA) due to its lower energy consumption and reduced environmental impact. However, CMAs often suffer from high moisture susceptibility, prolonged curing times, and inadequate mechanical performance. This study investigates the potential of calcium alginate capsules (CA capsules) containing waste sunflower oil (WSO) and waste engine oil (WEO) to improve CMA performance. Unlike previous research focusing on self-healing aspect of rejuvenating capsules, this work evaluates the impact of these CA capsules on curing efficiency, strength development, and mechanical behavior under different curing times and compaction methods: Marshall Compacted Mixture (MCM) and Gyratory Compacted Mixture (GCM). CA capsules were characterized using the Field Emission Scanning Electron Microscopy (FESEM)-EDS-Map and Thermogravimetric Analysis (TGA), and mechanical properties of CMA samples were assessed via indirect tensile strength (ITS), tensile strength ratio (TSR), rutting, and semi-circular bending (SCB) fracture tests.Weight measurements taken over the curing period showed that mixtures containing 0.5% CA capsules experienced greater moisture loss, thereby accelerating the curing process. GCM samples exhibited up to 90% higher ITS values than MCM samples, while samples with CA capsules showed an average 7–15% decrease in dry ITS. TSR values increased by up to 10% with 0.5% CA capsule addition, indicating improved moisture resistance. Fracture energy increased by 18–22% at − 20 °C in samples with 1% WSO, despite a slight reduction in fracture toughness. ANOVA analysis confirmed that compaction method had the greatest influence on ITS, TSR, and fracture energy, while CA capsule type mainly affected rutting depth. CA capsules with WEO led to deeper ruts than WSO, suggesting better compatibility of WSO with the asphalt matrix. These findings highlight that incorporating oil-based CA capsules—especially at 0.5–1% content—not only improves curing efficiency but also enhances the durability and sustainability of CMAs, particularly under low-temperature and high-moisture conditions.

Transarterial radioembolization (TARE) with β-emitting radionuclides is widely used for hepatocellular carcinoma (HCC), but its clinical efficacy remains to be further improved. α-particle-emitting radionuclides possess high linear energy transfer (LET) and unique advantages in cancer therapy, motivating α-particle based composite platform. Accordingly, we engineer the first clinically mimetic α-TARE microsphere by in-situ ²²³Ra-doped calcium–alginate composite microsphere (²²³Ra/Ca-ALG MS) using a hydrogel matrix, in which alginate “egg-box” coordination captures Ra²⁺ to provide stable radiolabeling, delivered via selective hepatic arterial injection to HCC. The microspheres exhibited excellent radiolabeling stability (88% retention after 384 h) and potent, dose-dependent cytotoxicity against HCC cells under hypoxia. In an orthotopic rat HCC model, 223 Ra/Ca-ALG MS-based TARE achieves precise intratumoral localization and sustained retention on SPECT/CT; ¹⁸F-FDG PET/CT and histopathology indicate a robust antitumor response, while serum biochemistry and histology support a favorable safety profile. Moreover, ²²³Ra/Ca-ALG MS provide powerful immune-activating capacity. Transcriptomics reveals activation of DNA-damage response, immunogenic cell death, and antigen-presentation pathways, flow cytometry and immunohistochemistry show increased dendritic-cell maturation and CD8⁺ T-cell infiltration. Collectively, 223 Ra/Ca-ALG MS demonstrates hypoxia-tolerant cytotoxicity, immune-activating potential, offering new insights for the development of immune-based TARE strategies in HCC and showing promising prospects for clinical translation. Graphical abstract