Sodium Alginate Chitosan Research Articles

In-situ Gelation of Sodium Alginate-chitosan for Oral Delivery of Probiotics

In-situ Gelation of Sodium Alginate-chitosan for Oral Delivery of Probiotics

Eco-Friendly Microwave Synthesis of Sodium Alginate-Chitosan Hydrogels for Effective Curcumin Delivery and Controlled Release.

In this study, we developed sodium alginate-chitosan hydrogels using a microwave-assisted synthesis method, aligning with green chemistry principles for enhanced sustainability. This eco-friendly approach minimizes chemical use and waste while boosting efficiency. A curcumin:2-hydroxypropyl-β-cyclodextrin complex was incorporated into the hydrogels, significantly increasing the solubility and bioavailability of curcumin. Fourier Transform Infrared Spectroscopy (FTIR) analysis confirmed the structure and successful incorporation of curcumin, in both its pure and complexed forms, into the polymer matrix. Differential scanning calorimetry revealed distinct thermal transitions influenced by the hydrogel composition and physical cross-linking. Hydrogels with higher alginate content had higher swelling ratios (338%), while those with more chitosan showed the lowest swelling ratios (254%). Scanning Electron Microscopy (SEM) micrographs showed a porous structure as well as successful incorporation of curcumin or its complex. Curcumin release studies indicated varying releasing rates between its pure and complexed forms. The chitosan-dominant hydrogel exhibited the slowest release rate of pure curcumin, while the alginate-dominant hydrogel exhibited the fastest. Conversely, for curcumin from the inclusion complex, a higher chitosan proportion led to the fastest release rate, while a higher alginate proportion resulted in the slowest. This study demonstrates that the form of curcumin incorporation and gel matrix composition critically influence the release profile. Our findings offer valuable insights for designing effective curcumin delivery systems, representing a significant advancement in biodegradable and sustainable drug delivery technologies.

Preparation of antibacterial composite aerogel for biomedical purposes based on alginate-chitosan complex and calcium carbonate

Aerogel composites were synthesized on the basis of the sodium alginate-chitosan interpolymer complex with the inclusion of calcium carbonate microparticles and supercritical drying. It is shown that the textural characteristics of materials do not depend on the morphology of calcium carbonate particles: the specific surface area of aerogels is almost the same for all materials and amounts to 380–400 m2/g. The developed porous structure of composites along with the polyelectrolyte nature determines their high water absorption— up to 110 g/g. To impart antimicrobial properties, the materials were impregnated with atranorin isolated from the lichen Hypogymnia physodes, which has a pronounced inhibitory effect on the bacterium Proteus mirabilis, which is the main causative agent of wound infections. The minimum suppressive concentration of atranorine is 1 mg/ml. The release of the main amount of atranorine aerosol material included in the matrix occurs within 4 hours and amounts to 50%.

Tuning the structure and physiochemical properties of sodium alginate and chitosan composite films through sodium tripolyphosphate (STPP) crosslinking

Sodium tripolyphosphate (STPP), an inorganic and non-toxic polyphosphate, has potential applications as a crosslinking agent in the fabrication of edible films. This study utilized STPP in the development of sodium alginate-chitosan composite films, with a focus on their suitability for food packaging applications. The results indicate that the incorporation of STPP led to an increase in film thickness (from 0.048 ± 0.004 to 0.078 ± 0.008 mm), elongation at break (from 11.50 ± 1.49 % to 15.88 ± 2.14 %), water permeation (from 0.364 ± 0.010 to 0.521 ± 0.021 gmm/(m2h*kPa)), and moisture content (from 25.98 ± 0.20 % to 28.12 ± 0.17 %). In contrast, there was a decrease in tensile strength (from 30.23 ± 2.08 to 25.60 ± 1.22 MPa) and swelling index (from 752.9 ± 17.1 to 533.5 ± 8.9 %). Scanning electron microscopy (SEM) analysis revealed the formation of distinctive needle-like microcrystals with the incorporation of STPP. Fourier-transform infrared spectroscopy (FTIR) analysis indicated intermolecular interactions between STPP and the film-forming biopolymers. The data obtained from Thermogravimetric analysis (TGA) and Differential Scanning Calorimetry (DSC) demonstrated enhanced thermal stability of STPP-loaded films at elevated temperatures. Furthermore, the films exhibited increased DPPH scavenging activity with the addition of STPP. This study underscores the potential of STPP as a crosslinking agent for the development of composite edible films, suggesting applications in the field of food packaging.

Alginate–Chitosan Polyelectrolyte Complexes As Carriers for Fluorinated Tetraphenylporphyrin in Photosensitizing Systems of Singlet Oxygen Generation

Water-insoluble photosensitizing (PS) systems active in the generation of singlet 1O2 oxygen are obtained by immobilizing fluorinated tetraphenylporphyrin (FTPP) from a solution in acetone on films of polyelectrolyte complexes based on sodium alginate (SA) and chitosan (CT), and on solid water-insoluble gels of alginate and chitosan. The obtained polymer PS systems are used to establish the intensity of the photoluminescence of singlet oxygen in D2O and the activity of the photocatalytic oxidation of tryptophan in water. It is shown that the photocatalytic activity in the tryptophan oxidation of fluorinated tetraphenylporphyrin immobilized on a SA–CT polyelectrolyte complex and alginate solid gel is higher than that of FTPP immobilized on chitosan solid gel. Spectral-luminescent properties of polysaccharide–FTPP systems and the surface structure of carriers are studied via atomic force microscopy to determine the mechanism of the increase in porphyrin activity when it is fixed on alginate-containing carriers. It is suggested that aspects of the supramolecular structure of solid gels are responsible for the increase in the photocatalytic activity of FTPP upon immobilization on alginate-containing polysaccharide systems.

Preparation and evaluation of chitosan-alginate/carrageenan hydrogel for oral drug delivery in the treatment of diabetes

Marine beds are an untapped resource of bioactive materials which can be explored for drug delivery applications. In the present study, a hydrogel was developed with an optimal concentration of sodium alginate-chitosan core polyelectrolytic complex loaded with anti-diabetic drug metformin and coated with ĸ-Carrageenan as an efficient oral drug delivery vehicle. The formulation was optimized by changing parameters such as concentration of polymers, amount of cross-linker and the type and amount of coating material. The prepared hydrogels were characterized for their structural integrity using instrumental techniques such as FTIR, XRD, DSC, and SEM while the physical properties were assessed by evaluating its thickness, UV barrier ability and swelling degree. In vitro study demonstrated the influence of presence and type of coating material affecting drug delivery process. The study suggested that coating with 3% ĸ-Carrageenan (A19) was found most suitable for oral drug delivery since it could resist diffusion of drug in the stomach (pH 1.2) so that maximum drug could reach the intestine (pH 7.4) for absorption. Metformin loaded hydrogel (A20) released ~49% drug in the simulated gastric fluid (pH 1.2). In the simulated intestinal fluid (pH 7.4) both the hydrogel exhibited a sustained release pattern lasting for more than 4 h. Investigation of drug release kinetics using different mathematical models showed that Higuchi model was the best fit release model with R2 ⩾ 0.973. The results indicated that the prepared hydrogels could be potential drug delivery vehicle toward intestine as well as for extended release to colon targeted drug delivery.

Rational design of porous structure-based sodium alginate/chitosan sponges loaded with green synthesized hybrid antibacterial agents for infected wound healing

An ideal wound dressing should have excellent antimicrobial properties and provide a suitable microenvironment for regenerating damaged skin tissue. In this study, we utilized sericin to biosynthesize silver nanoparticles in situ and introduced curcumin to obtain Sericin-AgNPs/Curcumin (Se-Ag/Cur) antimicrobial agent. The hybrid antimicrobial agent was then encapsulated in a physically double cross-linking 3D structure network (Sodium alginate-Chitosan, SC) to obtain the SC/Se-Ag/Cur composite sponge. The 3D structural networks were constructed through electrostatic interactions between sodium alginate and chitosan and ionic interactions between sodium alginate and calcium ions. The prepared composite sponges have excellent hygroscopicity (contact angle 51.3° ± 5.6°), moisture retention ability, porosity (67.32 % ± 3.37 %), and mechanical properties (>0.7 MPa) and exhibit good antibacterial ability against Pseudomonas aeruginosa (P. aeruginosa) and Staphylococcus aureus (S. aureus). In addition, in vivo experiments have shown that the composite sponge promotes epithelial regeneration and collagen deposition in wounds infected with S. aureus or P. aeruginosa. Tissue immunofluorescence staining analysis confirmed that the SC/Se-Ag/Cur complex sponge stimulated upregulated expression of CD31 to promote angiogenesis while downregulating TNF-α expression to reduce inflammation. These advantages make it an ideal candidate for infectious wound repair materials, providing an effective repair strategy for clinical skin trauma infections.

High-performance dual-sensitive flexible sensors based on conductive alginate sponge electrode/polyvinylidene fluoride microporous composite film

This work reported a novel dual-sensitive flexible sandwich sensor based on conductive natural biopolymers sponge electrode and polyvinylidene fluoride (PVDF) film with superiorities of high sensitivity, long lifespan and low density. The unique natural biopolymers sponge electrode, consisting of bidisperse magnetic particles and sodium alginate/chitosan (SA/CHI) with physically-crosslinked double-network structure, showed a high response capability to external magnetic fields. Besides, by combining the advantages of SA/CHI sponge electrode (high elasticity and flexibility) and PVDF film (exceptional stiffness and piezoelectricity), the SA/CHI/PVDF composite film also exhibited preferable mechanical strength and strain-dependent electrical property, which can simultaneously satisfy the requirements of high sensitivity detection to external magnetic fields and strains. Specifically, the relative resistance variation of SA/CHI/PVDF-1.00 sensor reached as high as 60.4% under a cycling loading of 240 mT magnetic field. Meanwhile, their electrical responses could also display a significant variation and relatively stable recoverability under periodic stretching, bending or compressing excitations. Afterwards, a potential working mechanism and equivalent circuit model were provided to study the magnetic/mechanic sensitivity of SA/CHI/PVDF sensors. Furthermore, a 4 × 4 SA/CHI/PVDF sensor array was developed to perceive and distinguish both magnetic field and compressive force, which indicated its favorable potential in wearable electronics and soft robotics.

Investigation into a Lightweight Polymeric Porous Sponge with High Magnetic Field and Strain Sensitivity.

Recently, flexible sensors have gained significant attention due to their potential applications in soft robotics and biomimetic intelligent devices. However, the successful production of favorable flexible sensors integrated with high flexibility, sensitivity and excellent environment adaptability toward multiple external stimuli is still an enormous challenge. Herein, a lightweight polymeric porous sponge capable of detecting an external magnetic field and strain excitations is proposed by assembling a sodium alginate/chitosan (SA/CHI) porous sponge with micron carbonyl iron and nanoscale Fe3O4 magnetic particles (MPs). Based on the double network structure, the SA/CHI sponge possesses preferable mechanical strength and hydrophilicity, demonstrating its high flexibility and deformability. More importantly, the electrical response of the SA/CHI sponge sensors can display remarkable variation under external magnetic and mechanical stimuli due to their superior magnetic characteristics and electrical conductivity. Meanwhile, their sensing properties can maintain relatively stable recoverability and repeatability towards the periodic excitations and releases. Additionally, a potential mechanism is provided to investigate their stimuli-sensitive behavior. It is highly dependent on the microstructure variations in MPs and conductive multi-walled carbon nanotube (MWCNTs) networks. Due to its exceptional magnetic controllability and appropriate electrical sensitivity, the proposed sensor shows high potential in wearable multi-sensing electronics and intelligent transport devices.

Janus hydrogel with dual antibacterial and angiogenesis functions for enhanced diabetic wound healing

Anti-infection and neovascularization at the wound site are two vital factors that accelerate diabetic wound healing. However, for a wound healing dressing, the two functions need to work at different sites (inner and outer), giving big challenges for dressing design. In this study, we fabricated a novel sodium alginate/chitosan (SA/CS) Janus hydrogel dressing by the assembly of SA hydrogel loaded with silver nanoparticles (AgNPs) and CS hydrogel impregnated with l-arginine loaded sodium alginate microspheres (ArgMSs) based on electrostatic interactions to combine the two functions. The outer SA-AgNP hydrogel could prevent infection while avoiding the deposition of AgNPs in the wound site, and the inner CS-ArgMS hydrogel on the wound surface could realize the sustained release of l-arginine and promote vascular regeneration. The composition, morphology and swelling/degradation of the SA-AgNP/CS-ArgMS hydrogel were characterized systematically. l-Arginine release behavior has been tested and SA-AgNP/CS-ArgMS hydrogel has been confirmed for excellent biocompatibility. Antibacterial and angiogenesis assays demonstrated the antibacterial and angiogenesis characteristics of the SA-AgNP/CS-ArgMS hydrogel. Finally, in vivo diabetic wound healing assay demonstrated that the SA-AgNP/CS-ArgMS hydrogel could significantly accelerate re-epithelialization, granulation tissue formation, collagen deposition and angiogenesis, thereby resulting in enhanced diabetic wound healing

Mucus-Penetrating Alginate-Chitosan Nanoparticles Loaded with Berberine Hydrochloride for Oral Delivery to the Inflammation Site of Ulcerative Colitis.

The rectal enemas of berberine hydrochloride (BH) have emerged as one of the most effective strategies in the clinical treatment of ulcerative colitis (UC). However, oral dosages of BH exhibit a poor anti-inflammatory effect of UC, which may attribute to premature absorption of BH by the upper gastrointestinal tract. Moreover, the thick colonic mucus layer obstructs the penetration of the drug, resulting in low bioavailability to the inflammatory site of the colon. The aim of this study was to develop the mucus-penetrating sodium alginate-chitosan nanoparticles (SA-CS NPs) for oral delivery of BH to the site of colonic ulcer lesions. BH-loaded SA-CS NPs were developed through the ionic gelation method and analyzed for physicochemical characteristics, release performance, penetrability, site retention, and therapeutic efficacy. The results showed that the NPs have a particle size of 257 nm with a negative charge, presenting desired pH-dependent release behavior. The permeation studies elucidated that negatively charged SA-CS NPs had 2.9 times higher mucus penetration ability than positively charged CS NPs. An ex vivo retention study indicated the high retention of BH-SA-CS NPs at the colon site for more than 16 h. In vivo therapeutic effectiveness demonstrated that the prepared NPs could not only alleviate colonic injury by decreasing the disease activity index and colon mucosa damage index, but also improve the immunologic function by decreasing the spleen index. In conclusion, the BH-SA-CS NPs could enhance the mucus permeability and deliver drugs to the colonic inflammation site, providing new insights into improving the therapeutic effect of UC.

Preparation, characterization and releasing property of antibacterial nano-capsules composed of ε-PL-EGCG and sodium alginate-chitosan

Aquatic products with high moisture and protein content are susceptible to bacterial growth and spoilage. Searching for efficient and safe natural antibacterial agents to preserve aquatic products has been concerned widely. In this study, ε-poly-lysine-epigallocatechin gallate/sodium alginate-chitosan nanoparticles (ε-PL-EGCG/SA-CS NPs) were prepared using sodium alginate and chitosan as wall materials and ε-PL-EGCG as core material. The size of nanoparticles was about 200 nm and the encapsulation efficiency was 78.2%. Transmission electron microscopy (TEM) images confirmed the prepared spherical nanoparticles. Fourier transform infrared spectroscopy (FTIR) and multifunctional polycrystalline X-ray diffraction (XRD) spectra indicated that ε-PL-EGCG was encapsulated in the nanoparticles. Thermo-gravimetric analysis (TGA) illustrated that the thermal stability of encapsulated ε-PL-EGCG was improved more than that of bare ε-PL-EGCG. In addition, in vitro release assays showed that the ε-PL-EGCG was released continuously over 36 h. Bacteria inhibition results showed that the ε-PL-EGCG/SA-CS NPs significantly inhibited specific spoilage bacteria E3 that screened out of aquatic products, Escherichia coli and Staphylococcus aureus. In conclusion, ε-PL-EGCG/SA-CS NPs are an effective antibacterial means with wide application prospects in the field of aquatic products preservation.

Aggregation enhances the activity and growth rate of anammox bacteria and its mechanisms

The aggregation of anaerobic ammonium oxidation (anammox) bacteria is important for the start-up and biomass retention of anammox processes. However, it is unclear whether it is beneficial to the activity, growth and reproduction of anammox bacteria. In this study, four reactor systems were developed to explore the effects of aggregation on anammox activity, growth and reproduction, after excluding the contribution of aggregation to sludge settling and retention. Results demonstrated that (i) compared with free-living planktonic bacteria, the aggregated bacteria had a higher volumetric nitrogen removal rate (0.75 kg-N/(m³·d)) and specific nitrogen removal activity (1.097 kg-N/VSS/d). And after 67 days cultivation, it had the higher sludge concentration and relative abundance (92.4%); (ii) compared with acidic polysaccharides and α-d-glucopyranose polysaccharides, β-d-glucopyranose polysaccharide play more essential roles of anammox aggregation; (iii) norspermidine triggered the secretion of α-d-glucopyranose polysaccharides to combat the toxicity, and inhibited biomass growth rate; (iv) immobilization in polyvinyl alcohol (10%) or sodium alginate (2%) gel beads was better than sodium alginate-chitosan gel beads and norspermidine (biofilm inhibitor) for the cultivation of free-living planktonic anammox bacteria. This is the first comparative study of three methods for cultivating free-living anammox bacteria. In conclusion, we found that the aggregation of anammox sludge not only facilitates biomass retention but also enhances the bioactivity, relative abundance, growth, and reproduction rate of anammox bacteria. The work is helpful to understand the formation of anammox granular sludge and contribute to the fast start-up and stable operation in anammox application.

Lollipop‐Inspired Multilayered Drug Delivery Hydrogel for Dual Effective, Long‐Term, and NIR‐Defined Glaucoma Treatment

Back Cover: Inspired by rainbow lollipop, a multilayered sodium alginatechitosan hydrogel ball decorated by zinc oxide-modified biochar is developed to reduce intraocular pressure. It is characterized by double drug loaded, duel effective, long-term and near-infrared adjustable, which may provide a meaningful development prospect for ocular drug delivery. This is reported by Feifei Wang and co-workers in article number 2100202.

Evaluation of debridement effects of bromelain-loaded sodium alginate nanoparticles incorporated into chitosan hydrogel in animal models.

Objective(s):Bromelain, a mixture of proteolytic enzymes from pineapple (Ananas comosus) is known as a potential debriding agent in burn treatment. In this research, the debridement efficiency of chitosan hydrogel loaded by sodium alginate-chitosan nanoparticles (NPs) containing bromelain (Br 10%-AG-CS NPs) was evaluated in animal models. Materials and Methods:The NPs were prepared using the ionic gelation technique and their properties were identified. Then, the debridement effect of bromelain NPs incorporated into chitosan hydrogel was evaluated 4 hr after wound treatment in animal models. Results:The particle size of positively charged Br-AG-Cs NPs was about 390±25 nm. The encapsulation efficiency of bromelain into AG-CS NPs was about 92%. The in vitro release profile showed that the maximum release of bromelain from NPs occurred during the first 4 hr (70%). The hydrogel structure did not significantly affect the profile release of bromelain in the formulation. After 6 months of storage at 4 and 25 °C, the synthesized NPs indicated no significant changes in bromelain activity. It was found that Br 10%-Ag-Cs NPs-CS hydrogel had the most beneficial effects on reducing necrotic tissues and resulted in re-epithelialization compared with other treated groups (negative and positive control, CS hydrogel, and Br 10%-CS hydrogel). Conclusion:Therefore, using this novel formulation can be considered a potential debridement agent.

Lollipop-Inspired Multilayered Drug Delivery Hydrogel for Dual Effective, Long-Term, and NIR-Defined Glaucoma Treatment.

Glaucoma is an ophthalmic disease that is characterized by elevated intraocular pressure (IOP). Eye drops are the preferred choice to reduce IOP for the treatment of glaucoma. However, the bioavailability of eye drops is low (<5%). Their long-term frequent administration cannot ensure patient compliance, which is the main reason for treatment failure. Inspired by lollipop, herein, a multilayered sodium alginate-chitosan (SA-CS) hydrogel ball (HB) decorated by zinc oxide-modified biochar (ZnO-BC) is developed as a new drug delivery system. The multilayer structure encapsulate timolol maleate (TM) and levofloxacin inside the different layers to realize the sustained release of drugs, which can control ocular hypertension and prevent infection effectively. The results show that the release of TM can be sustained in vitro for longer than 2 weeks. Moreover, IOP is also effectively reduced in vivo. Meanwhile, the photothermal conversion activity of ZnO-BC can regulate drug release on demand after stimulation by near-infrared irradiation. More importantly, the designed HB also shows good biocompatibility and antibacterial properties in vitro and in vivo. In summary, ZnO-BC-SA-CS HB can effectively reduce IOP and is expected to replace the classical tedious eye drop strategy, having potential utilization value in the treatment of glaucoma.

Fabrication and characterization of Chrysin – A plant polyphenol loaded alginate -chitosan composite for wound healing application

The present study explores the therapeutic efficacy of sodium alginate-chitosan scaffolds loaded with Chrysin (ALG-CS-CHY) for dermal wound management. Scaffolds were prepared by the vacuum freeze-drying method. The physiochemical characterization was done through Fourier Transform Infra-Red Spectroscopy (FTIR), which revealed the interactions between the scaffold's functional groups and the drug. Surface Electron microscopy (SEM) showed a porous architecture varying from 200-400 μm. X-ray Diffraction (XRD) showed an ionic interaction between ALG-CS leading to their excellent compatibility. Differential Scanning Calorimetry (DSC) and Thermogravimetric Analysis (TGA) results suggest increased ALG-CS scaffold's thermal stability. In-vitro biodegradation behavior demonstrated controlled degradation with lysozyme. The swelling ratio was highest in the first hour and decreased slowly with time, and the porosity analysis showed a high degree of porosity. The ALG-CS scaffold showed sustained drug availability and minimized re-application, which contributes to effective healing and treatment. The blood compatibility and whole blood clotting ability of the scaffold significantly improved after incorporating the drug. Calcein AM, Propidium iodide, was used for live and dead cell staining, which confirmed that fabricated ALG-CS-CHY scaffolds are biocompatible and facilitate cell growth and cell proliferation. In-vivo and in-vitro observations show that the experimental group treated using the ALG-CS-CHY reduces the period of re-epithelization, accelerated fibroblast cell migration, and contracted wound significantly (p < 0.001) compared to other groups. ALG-CS-CHY scaffolds also increased collagen deposition, hexosamine synthesis, accelerates angiogenesis, and recruiting immune cells at the site of a wound. These results suggest ALG-CS-CHY scaffold serves as an effective dressing for dermal wound management.

Flexible conductive sodium alginate/chitosan foam with good mechanical properties and magnetic sensitivity

In this study, a novel flexible conductive sodium alginate/chitosan (SA/CS) foam with double-network structure based on dual-coated magnetic particles (MPs) was prepared by a biological crosslinking process of natural biopolymers. The structural characterization, response deformation and magnetic-field-dependent electric performance for different foams were investigated, and they were significantly dependent on the mass ratio of SA/CS, the contents of glycerol and MPs. By increasing SA and CS, the electrostatic interactions of double-network enhanced, leading to an increase in its binding force with the MPs, so the magnetic-responsive performance was strongly improved. Meanwhile, the resistance displayed a remarkable variation under the magnetic fields. For instance, the resistance of the sample with a mass ratio of 3:3 decreased with the magnetic flux densities (0.10–0.40 T) and it ranged from 14.8–6.83 kΩ, which reduced by about 53.9%. Moreover, the periodic measurements were applied so as to verify its recoverability and repeatability. Furthermore, a possible mechanism was provided to explain the magnetic-responsive behavior of the samples. Because of the superior magnetic controllability and preeminent mechanical performance, the conductive porous foam is promising in the fields of artificial electric skins, soft sensors and actuators.

Alginate-chitosan oligosaccharide-ZnO composite hydrogel for accelerating wound healing

Moist, breathable and antibacterial microenvironment can promote cell proliferation and migration, which is beneficial to wound healing. Here, we fabricated a novel sodium alginate-chitosan oligosaccharide‑zinc oxide (SA-COS-ZnO) composite hydrogel by spontaneous Schiff base reaction, using aldehydated sodium alginate (SA), chitosan oligosaccharide (COS), and zinc oxide (ZnO) nanoparticles, which can provide a moist and antibacterial environment for wound healing. The porosity and swelling degree of SA-COS-ZnO hydrogel are 80% and 150%, respectively, and its water vapor permeability is 682 g/m2/24h. The composite hydrogel showed good biocompatibility to blood cells, 3T3 cells, and 293T cells, and significant antibacterial activity against Escherichia coli, Staphylococcus aureus, Candida albicans, and Bacillus subtilis. Moreover, the hydrogel showed a promoting effect on wound healing in a rat scald model. The present study suggests that marine carbohydrates composite hydrogels are promising in wound care management.

Modulating layer-by-layer assembled sodium alginate-chitosan film properties through incorporation of cellulose nanocrystals with different surface charge densities

In this work, 2,2,6,6-tetramethylpiperidine-1-oxyl-oxidized cellulose nanocrystals (TOCNs) were loaded into sodium alginate/chitosan multilayer film as nanofillers to investigate the modulation of the surface charge density of TOCNs on the film properties. First, the surface charge density of TOCNs was controlled by adjusting the carboxyl content and morphological size by varying the oxidant dosage. After oxidation, TOCN with higher surface charge density was observed to display a higher crystallinity, a more open internal structure, a better dispersibility and a slightly weaker thermal stability. In addition, a 15-layer film composed of sodium alginate and chitosan, called (SA/CH)15, was constructed by layer-by-layer assembly. Both in situ deposition monitoring and free-standing multilayer film formation indicated that TOCNs relied on strong electrostatic interactions and hydrogen bonding to achieve a compact and uniform interlayer and a thinner thickness of (SA/CH)15, which was more evident at a high surface charge density. The addition of TOCNs also enhanced the mechanical properties, thermal stability, hydrophobicity, and barrier properties of (SA/CH)15. In particular, the resulting sodium alginate/chitosan multilayer film exhibited an improved packaging performance when nanocomposite was performed using TOCN with a surface charge density of 3.22 ± 0.11 e nm−2.