Search Results (45)

The aim of this study was to develop double emulsions-filled chitosan hydrogel beads for topical application and to elucidate their skin penetration behavior. Double emulsions were prepared by a two-step emulsification method, and double emulsions-filled chitosan hydrogel beads were prepared by the extrusion method. The structure, stability, and skin penetration behavior were investigated. The results of yield efficiency (above 80%) and microstructure observation confirmed the feasibility of the preparation method. After loading the hydrophilic active ingredients (vitamin C) into this system, the retention ratio after storage for 6 weeks increased by 77.6%. Furthermore, hydrogel beads could promote the permeation of hydrophilic active ingredients loaded in double emulsions. When the concentration of chitosan was 3% (w/v), the permeation coefficient of vitamin C from hydrogel beads exhibited an increase (1.7-fold) compared with double emulsions. This system could affect the orderliness of lipid structures in the stratum corneum. In addition, the results indicated that this system could be used for the topical delivery of hydrophobic active ingredients (quercetin) as well. This is the first report of chitosan bead stabilization of W/O/W emulsions, yielding a 2.6-fold increase in skin uptake of hydrophilic actives. Full article

Currently, as research on hydrogel beads intensifies, the application scope of chitosan-based hydrogel beads is increasingly expanding. Owing to their unique three-dimensional network structure, chitosan-based hydrogel beads are frequently utilized for encapsulating bioactive substances and adsorbing impurities. The primary material used in the preparation of chitosan-based hydrogel beads is chitosan, which is uniquely a natural polysaccharide possessing a positive charge. Derived from a diverse array of sources, chitosan is non-toxic, exhibits excellent biocompatibility, and possesses certain antibacterial properties. Because of these remarkable attributes, it has found widespread application in tissue engineering, the formulation of drug carriers, and the adsorption of heavy metals and dyes in wastewater. The preparation method for chitosan-based hydrogel beads largely mirrors that of other hydrogel beads. According to existing research, numerous methods exist for crafting hydrogel beads with diverse properties. This paper reviews the preparation methods of chitosan-based hydrogel beads, encompassing both physical and chemical crosslinking techniques. The physical crosslinking method leverages electrostatic interactions between materials to form hydrogel beads, whereas the chemical crosslinking method involves the use of chemical crosslinking agents to facilitate the formation of hydrogel beads through material-based chemical reactions. Given that chitosan carries a positive charge and other polysaccharide materials possess a negative charge, the combination of these materials can yield hydrogel beads with a dense structure, effectively encapsulating bioactive substances. This dense internal structure offers superior protection for the encapsulated bioactive substances. Chitosan-based hydrogel beads typically feature large pore sizes, providing numerous adsorption sites, which makes them well suited for wastewater treatment. Additionally, this paper examines the recent applications of chitosan-based hydrogel beads in food preservation, medicine, and environmental protection. Starting with the materials and methods for preparing chitosan-based hydrogel beads, this paper delves into their applications in food preservation, biomedicine, and environmental protection, offering insights for future developments and applications of chitosan-based hydrogel beads and fostering further innovation and advancement in this field. Full article

Hydrogel-based adsorbents have gained increasing recognition in recent years due to their promising potential for pollutant removal. However, conventional hydrogels often suffer from low mechanical strength over prolonged use. Therefore, this study explores the incorporation of silica extracted from bamboo culm (Dendrocalamus asper) to enhance the mechanical stability of hydrogel beads composed from carboxymethyl cellulose (CMC), chitosan (CS), and magnetite ferrofluid (Fe₃O₄), through cross-linking. We hypothesize that silica enhances the mechanical properties of magnetite hydrogel beads without compromising their adsorption capacity. The extracted silica was confirmed with FTIR and EDS analysis. The synthesized CMC-CS-Fe₃O₄-Si hydrogel beads were characterized using FTIR and SEM. Its stability was assessed through dry weight loss measurements, while its adsorption efficiency was evaluated using batch adsorption experiments. The silica-incorporated hydrogel exhibited enhanced mechanical and thermal stability under various pH and temperature conditions, without negatively affecting its adsorption performance, achieving maximum adsorption capacities of 53.00 mg/g for Cr (VI) and 85.06 mg/g for Cu (II). Desorption and regeneration studies confirmed the reusability of the hydrogel for more than four cycles. Overall, the interaction between the hydrogel and silica resulted in excellent adsorption performance, improved mechanical properties, and long-term reusability, making this a promising hydrogel adsorbent for wastewater remediation. Full article

Background: Despite extensive research over the decades, cancer therapy is still a great challenge because of the non-specific delivery of chemotherapeutic agents, which could be overcome by limiting the distribution of chemotherapeutic agents toward cancer cells. Objective: To reduce the cytolytic effects against cancer cells, graphene oxide (GO) nanoparticles (NPs) can load anticancer medicines and genetic tools. Methodology: During the current study, folic-acid-conjugated graphene oxide (Fa-GO) hybrid mucoadhesive chitosan (CS)-based hydrogel beads were fabricated through an “ion-gelation process”, which allows for regulated medication release at malignant pH. Results: The fabricated chitosan–alginate (SA-CS) hydrogel beads were examined using surface morphology, optical microscopy, XRD, FTIR, and homogeneity analysis techniques. The size analysis indicated that the size of the Fa-GO was up to 554.2 ± 95.14 nm, whereas the beads were of a micrometer size. The folic acid conjugation was confirmed by NMR. The results showed that the craggy edges of the graphene oxide were successfully encapsulated in a polymeric matrix. The mucoadhesive properties were enhanced with the increase in the CS concentration. The nanohybrid SA-CS beads exhibited good swelling properties, and the drug release was 68.29% at pH 5.6 during a 24 h investigation. The accelerated stability study, according to ICH guidelines, indicated that the hydrogel beads have a shelf-life of more than two years. Conclusions: Based on the achieved results, it can be concluded that this novel gastro-retentive delivery system may be a viable and different way to improve the stomach retention of anticancer agents and enhance their therapeutic effectiveness. Full article

Designing a wound dressing with controlled uptake, antibacterial, and proper biocompatibility is crucial for the appropriate wound healing process. In this study, alginate/tetracycline (Alg/TC) beads were produced and embedded into chitosan/pluronic/agarose semi-interpenetrating polymer network hydrogel, which serves as a potential biocompatible dressing for treating skin wounds. The effect of pluronic content on the porosity, swelling, mechanical characteristics, and degradation of the hydrogel was investigated. Furthermore, the impact of Alg beads on TC release was subsequently examined. In the absence of Alg beads, faster release was observed. However, after incorporating beads into the hydrogels, the release was sustained. Particularly, the hydrogel containing Alg beads exhibited a nearly linear release, reaching 74% after 2 days in acidic media. The antimicrobial activity and biocompatibility of the hydrogel were also evaluated to assess the capability of the TC-loaded hydrogels for wound dressing applications. The hydrogel demonstrated efficient antibacterial features against Gram-positive and Gram-negative bacteria. Additionally, the sample behavior was evaluated against exposure to yeast. Furthermore, based on biocompatibility studies using HFF2 cells, the TC-loaded hydrogel exhibited remarkable biocompatibility. Overall, this novel composite hydrogel shows remarkable biocompatibility and antibacterial activities which can be used as a great potential wound dressing to prevent wound infections due to its effective inhibition of bacterial growth. Full article

A common challenge in hydrogel-based delivery systems is the premature release of low molecular weight encapsulates through diffusion or swelling and reduced cell viability caused by the low pH in gastric conditions. A second biopolymer, such as chitosan, can be incorporated to overcome this. Chitosan is usually associated with colonic drug delivery systems. We intended to formulate chitosan-coated pectin beads for use in delaying premature release of the encapsulate under gastric conditions but allowing release through disintegration under intestinal conditions. The latter is of utmost importance in delivering most functional food ingredients. Therefore, this study investigated the impact of formulation and process conditions on the size, sphericity, and dissolution behavior of chitosan-coated hydrogel beads prepared by interfacial coacervation. The size and sphericity of the beads depend on the formulation and range from approximately 3 to 5 mm and 0.82 to 0.95, respectively. Process conditions during electro-dripping may be modulated to tailor bead size. Depending on the voltage, bead size ranged from 1.5 to 4 mm. Confocal laser scanning microscopy and scanning electron microscopy confirmed chitosan shell formation around the pectin bead. Chitosan-coated beads maintained their size and shape in simulated gastric fluid but experienced structural damage in simulated intestinal fluid. Therefore, they represent a novel delivery system for functional food ingredients. Full article

Chitosan and its derivatives, known for their unique molecular structures and advantageous biological properties, have emerged as promising candidates for diverse applications, particularly in the realm of water treatment. This study investigated the effectiveness of chitosan hydrogel beads combined with activated carbon in removing lead from contaminated water sources. The overarching objective of this research endeavor is to develop a sustainable and cost-effective wastewater treatment system, aligning with Qatar Vision 2030’s emphasis on sustainable development goals. Experimental investigations were conducted to fabricate chitosan hydrogel beads and assess their characteristics through rigorous FTIR and ICP-OES analyses. Notably, the incorporation of activated carbon with chitosan significantly enhanced lead removal efficacy, achieving removal efficiencies ranging from 80.29% to 96.48% with various activated carbon mixtures, indicating promising opportunities for further optimization. The FTIR analysis showed that incorporating activated carbon into chitosan beads resulted in distinct changes in the IR spectra. AC-chitosan beads exhibited broad -OH peaks at 3272 cm⁻¹ and a stretch at 1639 cm⁻¹, which were less pronounced or absent in isolated chitosan beads. Both types showed a peak at 1376 cm⁻¹, with higher intensity in regular chitosan beads. Beyond underscoring the importance of chitosan-based materials in water treatment, this study also provides insightful recommendations for future research endeavors aimed at fostering awareness and facilitating practical applications, thereby bolstering environmental conservation and sustainable water management initiatives. Full article

Wireless soft miniature robots have been studied for biomedical applications. However, the wireless soft miniature robots developed so far are mainly composed of synthetic polymers that do not guarantee biocompatibility and biodegradability. Additionally, current soft robots have limitations in demonstrating mobility in narrow spaces, such as blood vessels within the body, by using their flexible body. This study proposes a wireless hybrid-actuated soft miniature robot for biomedical applications. The proposed soft miniature robot consists of biodegradable chitosan and magnetic nanoparticles (MNPs) and is fabricated into an eight-arm shape by laser micromachining. The soft miniature robot can implement hydrogel swelling and magnetic-actuated shape morphing by using the difference in MNP density and magnetic field responsiveness within the robot body, respectively. Furthermore, the soft miniature robot can be guided by external magnetic fields. As feasibility tests, the soft miniature robot demonstrated on-demand pick-and-place motion, grasping a bead, moving it to a desired location, and releasing it. Furthermore, in an in-channel mobility test, the flexible body of the soft miniature robot passed through a tube smaller in size than the robot itself through magnetically actuated shape morphing. These results indicate that the soft miniature robot with controllable shape change and precise magnetic-driven mobility can be a minimally invasive surgical robot for disease diagnosis and treatment. Full article

Covalent cross-linked hydrogels based on chitosan and poly(maleic acid-alt-vinyl acetate) were prepared as spherical beads. The structural modifications of the beads during the preparation steps (dropping in liquid nitrogen and lyophilization, thermal treatment, washing with water, and treatment with NaOH) were monitored by FT-IR spectroscopy. The hydrogel beads have a porous inner structure, as shown by SEM microscopy; moreover, they are stable in acidic and basic pH due to the covalent crosslinking. The swelling degree is strongly influenced by the pH since the beads possess ionizable amine and carboxylic groups. The binding capacity for Cu²⁺ ions was examined in batch mode as a function of sorbent composition, pH, contact time, and the initial concentration of Cu²⁺. The kinetic data were well-fitted with the pseudo-second-order kinetic, while the sorption equilibrium data were better fitted with Langmuir and Sips isotherms. The maximum equilibrium sorption capacity was higher for the beads obtained with a 3:1 molar ratio between the maleic copolymer and chitosan (142.4 mg Cu²⁺ g⁻¹), compared with the beads obtained using a 1:1 molar ratio (103.7 mg Cu²⁺ g⁻¹). The beads show a high degree of reusability since no notable decrease in the sorption capacity was observed after five consecutive sorption/desorption cycles. Full article

The objective of the present study was to develop and evaluate NLC–chitosan hydrogel beads for topical administration. The feasibility of the preparation technology was verified by investigating various formulation factors and the impact of chitosan hydrogel beads on the NLC. The encapsulation efficiency of NLC–chitosan hydrogel beads was above 95% in optimized process conditions. The physical characterization of the NLC–chitosan hydrogel beads showed that the NLC was distributed within the network of the chitosan hydrogel beads. Furthermore, the incorporation of NLC into the chitosan hydrogel beads was related to the electrostatic interaction between the surface of the NLC and chitosan, which influenced the lipid ordering degree of the NLC and contributed to the stability. The stability studies showed that the retention rate of quercetin in the NLC–chitosan hydrogel beads was 88.63 ± 2.57% after 10 months of storage under natural daylight. An in vitro permeation study showed that NLC–chitosan hydrogel beads exhibited superior ability in enhancing skin permeation by hydrophobic active ingredients compared to the NLC and significantly increased skin accumulation. These studies demonstrated that the use of NLC–chitosan hydrogel beads might be a promising strategy for the delivery of hydrophobic active ingredients in topical administration. Full article

This study investigates the viability of developing chitosan-based hydrogels derived from waste shrimp shells for the removal of methylene blue and methyl orange, thereby transforming food waste into advanced materials for environmental remediation. Despite chitosan-based adsorbents being conventionally considered ideal for the removal of negative pollutants, through targeted functionalization with poly(3,4-ethylenedioxythiophene): polystyrene sulfonate (PEDOT:PSS) at varying concentrations, we successfully enhance the hydrogels’ efficacy in also adsorbing positively charged adsorbates. Specifically, the incorporation of PEDOT:PSS at a concentration of 10% v/v emerges as a critical factor in facilitating the robust adsorption of dyes. In the case of the anionic dye methyl orange (MO, 10⁻⁵ M), the percentage of removed dye passed from 47% (for beads made of only chitosan) to 66% (for beads made of chitosan-PEDOT:PSS 10%), while, in the case of the cationic dye methylene blue (MB, 10⁻⁵ M), the percentage of removed dye passed from 52 to 100%. At the basis of this enhancement, there is an adsorption mechanism resulting from the interplay between electrostatic forces and π–π interactions. Furthermore, the synthesized functionalized hydrogels exhibit remarkable stability and reusability (at least five consecutive cycles) in the case of MB, paving the way for the development of cost-effective and sustainable adsorbents. This study highlights the potential of repurposing waste materials for environmental benefits, introducing an innovative approach to address the challenges regarding water pollution. Full article

Fixed-bed columns packed with chitosan-magnetite (ChM) hydrogel and chitosan (Ch) hydrogel were used for the removal of arsenate ions from aqueous solutions at a pH of 7.0. The effect of flow rate (13, 20, and 25 mL/h), height of the columns (13 and 33 cm), and initial arsenate concentration (2, 5 and 10 mg/L) on the column’s efficiency for the removal of As(V) is reported. The maximum adsorption capacity (q_b), obtained before the allowed concentration of contaminant is exceeded, the adsorption capacity (q_e) when the column is exhausted, and the mass transfer zone were determined. With this information, the efficiency of the column was calculated, which is given by the H_L/H_LUB ratio. The higher this ratio, the higher the efficiency of the column. The highest efficiency and the highest uptake capacity value at breakthrough point were obtained when using the lower flow rate, lower initial arsenate concentration, and longer bed length. When 33 cm-high columns were fed with a 10 mg As(V)/L solution at 13 mL/h, the maximum uptake capacity values at exhaustion obtained for Ch and ChM were 1.24 and 3.84 mg/g, respectively. A pH increase of the solution at the column’s exit was observed and is attributed to the proton transfer from the aqueous solution to the amino and hydroxyl groups of chitosan. The incorporation of magnetite into Ch hydrogels significantly increases their capacity to remove As(V) due to the formation of complexes between arsenic and the magnetite surface. Experimental data were fitted to the Thomas model, the Yoon–Nelson model and the Bohart–Adams model using non-linear regression analysis. Full article

To address the challenges associated with the weak affinity and difficult separation of biochar, we developed chitosan–biochar hydrogel beads (CBHBs) as an efficient solution for removing reactive brilliant blue (RBB KN-R) from wastewater. The adsorption behavior and mechanism of RBB KN-R onto CBHBs were extensively studied. Notably, the adsorption capacity of RBB KN-R showed pH-dependence, and the highest adsorption capacity was observed at pH 2. The adsorption process was well fitted with the pseudo-second-order kinetic model and the intraparticle diffusion model. Film diffusion and intraparticle diffusion were both responsible for the adsorption of RBB KN-R onto CBHBs. At 298.15 K, the maximum adsorption capacity q_m was determined to be 140.74 mg/g, with higher temperatures favoring the adsorption process. A complex mechanism involving π–π interactions, electrostatic attraction, hydrophobic interaction, and hydrogen bonding was found to contribute to the overall adsorption process. The experimental data discovered the coexisting substances and elevated ionic strength hindered the adsorption capacity. Significantly, after three cycles of adsorption–desorption, the CBHBs maintained an adsorption capacity above 95% for RBB KN-R. These promising results imply that CBHBs are a durable and cost-effective adsorbent for efficient removal of dyes from wastewater. Full article

Blended biopolymer-based photocatalytic hydrogel beads were synthesized by dissolving the biopolymers in 1-ethyl-3-methylimidazolium acetate ([Emim][Ac]), adding TiO₂, and reconstituting the beads with ethanol. The incorporation of modifying biopolymer significantly enhanced the adsorption capacity of the cellulose/TiO₂ beads. Cellulose/carrageenan/TiO₂ beads exhibited a 7.0-fold increase in adsorption capacity for methylene blue (MB). In contrast, cellulose/chitosan/TiO₂ beads showed a 4.8-fold increase in adsorption capacity for methyl orange (MO) compared with cellulose/TiO₂ beads. In addition, cellulose/TiO₂ microbeads were prepared through the sol–gel transition of the [Emim][Ac]-in-oil emulsion to enhance photodegradation activity. These microbeads displayed a 4.6-fold higher adsorption capacity and 2.8-fold higher photodegradation activity for MB than the millimeter-sized beads. Furthermore, they exhibited superior dye removal efficiencies for various dyes such as Congo red, MO, MB, crystal violet, and rhodamine B, surpassing the performance of larger beads. To expand the industrial applicability of the microbeads, biopolymer/TiO₂ magnetic microbeads were developed by incorporating Fe₂O₃. These magnetic microbeads outperformed millimeter-sized beads regarding the efficiency and time required for MB removal from aqueous solutions. Furthermore, the physicochemical properties of magnetic microbeads can be easily controlled by adjusting the type of biopolymer modifier, the TiO₂ and magnetic particle content, and the ratio of each component based on the target molecule. Therefore, biopolymer-based photocatalytic magnetic microbeads have great potential not only in environmental fields but also in biomedical fields. Full article

Heavy metals, such as chromium (VI) and lead (II), are the most common pollutants found in wastewater. To solve these problems, this research was intended to synthesize magnetite hydrogel beads (CMC-CS-Fe₃O₄) by crosslinking carboxymethyl cellulose (CMC) and chitosan (CS) and impregnating them with iron oxide (Fe₃O₄) as a potential adsorbent to remove Cr (VI) and Pb (II) from water. CMC-CS-Fe₃O₄ was characterized by pH_zpc, scanning electron microscopy (SEM), and Fourier-transform infrared spectroscopy (FTIR). Batch removal experiments with different variables (CMC:CS ratio, pH, initial metals concentration, and contact time) were conducted, and the results revealed that CMC-CS-Fe₃O₄ with a CMC:CS (3:1) ratio had the best adsorption capacity for Cr (VI) and Pb (II) at pH levels of 2 and 4, respectively. The findings of this research revealed that the maximum adsorption capacity for Cr (VI) and Pb (II) were 3.5 mg/g and 18.26 mg/g, respectively, within 28 h at 30 $℃$. The adsorption isotherm and adsorption kinetics suggested that removal of Cr (VI) and Pb (II) were fitted to Langmuir and pseudo-second orders. The highest desorption percentages for Cr (VI) and Pb (II) were 70.43% and 83.85%, achieved using 0.3 M NaOH and 0.01 M N$·$a2EDTA, respectively. Interestingly, after the first cycle of the adsorption–desorption process, the hydrogel showed a sudden increase in adsorption capacity for Cr (VI) and Pb (II) until it reached 7.7 mg/g and 33.0 mg/g, respectively. This outcome may have certain causes, such as entrapped metal ions providing easy access to the available sites inside the hydrogel or thinning of the outer layer of the beads leading to greater exposure toward active sites. Hence, CMC-CS-Fe₃O₄ hydrogel beads may have potential application in Cr (VI) and Pb (II) removal from aqueous solutions for sustainable environments. Full article