Modified Chitosan Hydrogel Research Articles

Copper ion-doped multifunctional hydrogel with mild photothermal enhancement promotes vascularized bone regeneration.

The design and construction of a new and excellent synthetic graft is of great significance in the field of bone defect repair and reconstruction. In this study, a dopamine modified chitosan hydrogel doped with Cu ions with a mild photothermal effect was designed to provide a better microenvironment to advance the bone repair via promote the angiogenesis and osteogenesis. Characterizations showed the successful synthesis of the material while it also presented excellent biocompatibility and mild photothermal effect under the irradiation of near-infrared light. Further, it could enhance the angiogenesis of HUVECs cells through promoting the ability of migration and tube formation and enhance the osteogenic differentiation of MC3T3-E1 cells via increasing the content of vital osteogenic factors including Runx2, Col-1, OPN, OCN, OSX, etc. The in vivo experiment also testified that it could promote the bone defect repair in rat models. These results indicate the multifunctional hydrogel is an ideal material for the treatment of bone defects and has good clinical application potential.

ZIF-67 loaded thio-groups modified chitosan hydrogel for high efficient Hg(II) removal from water

In the past few years, there has been an increasing worry about the pollution of water caused by the presence of heavy metals. To address this environmental issue, a highly effective adsorbent called ZIF-67/CS-SH was developed. This adsorbent was prepared by grafting thioglycolic acid and loading a metal-organic framework called ZIF-67 onto chitosan, to remove Hg(II) from water. Confirmation of the ZIF-67/CS-SH was achieved by employing a range of techniques including FTIR, XRD, TGA, SEM, EDS, BET, and XPS. Due to the presence of abundant active sites (-SH, O/N-containing functional groups) and ZIF-67, ZIF-67/CS-SH exhibited a high adsorption capacity (949 mg/g at 298 K) and rapid adsorption kinetics (20 min for 91 % removal). The optimal pH for the adsorption process was found to be 5. The adsorption process followed a pseudo-second-order kinetics and Langmuir isotherm, with chemisorption being the main adsorption mechanism. The adsorption process was determined to be spontaneous and endothermic. Additionally, ZIF-67/CS-SH demonstrated selective adsorption in the presence of other metal cations at concentrations of 100 mg/L. Furthermore, ZIF-67/CS-SH exhibited excellent regenerative properties, with only a 10 % decrease in adsorption capacity after ten cycles. The key adsorption sites were identified as the –SH groups, O/N-containing functional groups, and ZIF-67 in ZIF-67/CS-SH through FTIR, EDS, and XPS analyses. Considering its outstanding performance in removing Hg(II), ZIF-67/CS-SH shows promise for application in industrial wastewater treatment.

Dopamine-Modified Chitosan Patterning Hydrogel with Dynamic Information Storage Ability.

The storage of dynamic information in hydrogels has aroused considerable interest regarding the multiple responsiveness of soft matter. Herein, we propose an electrical writing methodology to prepare dopamine (DA)-modified chitosan hydrogels with a dynamic information storage ability. A pH-responsive chitosan hydrogel medium was patterned by cathodic writing to in situ generate OH- in the writing area, at which dopamine underwent an auto-oxidation reaction in the locally alkaline environment to generate a dark color. The patterned information on the hydrogel can be encoded simply by electrical signals. The speed of information retrieval is positively correlated with the charge transfer during the electrical writing process, and the hiding of information is negatively correlated with the environmental stimulus (i.e., dopamine concentration, pH value, etc.). To showcase the versatility of this medium for information storage and the precision of the pattern, a quick response (QR) code is electronically written on dopamine-modified chitosan hydrogel and can be recognized programmably by a standard mobile phone. The results show that electrical regulation is a novel means to program the information storage process of hydrogels, which inspires future research on structural and functional information storage using stimulus-responsive hydrogels.

Succinic acid modified chitosan hydrogel mediates in-situ bioenergetic remodeling of neural cells for neuronal differentiation and spinal cord injury repair

A primary challenge in spinal cord injury repair is the presence of an energy deficit, exacerbated by the injury itself, thereby intensifying the dilemma of insufficient energy. Hence, we posit a hypothesis suggesting that the adoption of a direct energy-supply material strategy has the potential to enhance in situ cellular energy levels, facilitating the acceleration of neuronal differentiation and axonal elongation. We successfully designed a degradable bioenergetic hydrogel by introducing succinic acid (SA), a key intermediate in tricarboxylic acid (TCA) cycle, into chitosan (CS) as an energy-active unit, which was released in a sustained degradation-mediated fashion once implanted. The degraded energy-active units, after being internalized, increased bioenergetic levels via oxidative phosphorylation (OXPHOS) by facilitating TCA flux, thereby contributing to a at least 1.5-fold increase in the expression levels of neuronal differentiation-related markers in vitro, as well as the enhanced spinal cord injury repair and functional recovery in vivo. Further mechanism analysis demonstrated that the upregulation of the bioenergetic basis had the potential to induce neuronal differentiation through the AMP-activated protein kinase-mammalian target of rapamycin (AMPK-mTOR) axis. Additionally, the adenosine triphosphate (ATP) itself acted as a signaling molecule via the P2X7 receptor, leading to the upregulation of intracellular calcium ion-MAPK signal cascades, ultimately promoting neuronal differentiation. Overall, these findings have the potential to significantly alter our understanding of cell metabolism and energy homeostasis, transforming them from passive observers to critical factors in guiding nerve regeneration, and may have implications for future design of bioenergetic-active materials.

Single-Step Fabrication of a Dual-Sensitive Chitosan Hydrogel by C-Mannich Reaction: Synthesis, Physicochemical Properties, and Screening of its Cu2+ Uptake

Uncovering the value of waste materials is one of the keys to sustainability. In this current work, valorization of chitosan was pursued to fabricate a novel modified chitosan functional hydrogel using a process-efficient protocol. The fabrication proceeds by a one-pot and single-step C-Mannich condensation of chitosan (3% w/v), glutaraldehyde (20 eq.), and 4-hydroxycoumarin (40 eq.) at 22 °C in 3% v/v acetic acid. The Mannich base modified chitosan hydrogel (CS-MB) exhibits a dual-responsive swelling behavior in response to pH and temperature that has not been observed in any other hydrogel systems. Combining the pre-defined optimal swelling pH (pH = 4) and temperature (T = 22 °C), the CS-MB was screened for its Cu2+ adsorption capacity at this condition. The CS-MB achieved an optimal adsorption capacity of 12.0 mg/g with 1.2 g/L adsorbent dosage after 36 h with agitation. The adsorption of Cu2+ on the surface of CS-MB was verified by EDS, and an overview of the adsorption sites was exhibited by FT-IR. The simply fabricated novel CS-MB hydrogel under investigation presents a unique response to external stimuli that exhibits a promise in heavy metal removal from aqueous media.

Graphene Oxide-Carbamoylated Chitosan Hydrogels with Tunable Mechanical Properties for Biological Applications.

Chitosan (CH)-based hydrogels have been extensively researched in numerous biological applications, including drug delivery, biosensing, wound healing, and tissue engineering, to name a few. Previously, modified CH hydrogels by carbamoylation, using potassium cyanate (KCNO) as the cross-linker, have shown improvement in viscoelastic properties and biocompatibility. In this study, graphene oxide (GO) nanofillers are added to carbamoylated CH to form a nanocomposite hydrogel and study the influence of CH molecular weight (Mw) and GO loading concentrations on hydrogel properties. The physical properties (swelling, degradation, and porous structure) of the hydrogels can be tuned as required for cell attachment and spreading by varying both the GO concentration and the Mw of CH. Rheological characterization showed an improvement in the mechanical properties (storage modulus, yield stress, and viscosity) of the synthesized CH-GO hydrogels with an increase in the Mw of CH and the GO concentration. Human retinal pigmented epithelial-1 (RPE-1) cells seeded onto the prepared hydrogel scaffolds showed good cell viability, adhesion, and cell spreading, confirming their cytocompatibility, with dependence on both Mw of CH and GO loading.

Dopamine-modified chitosan hydrogel for spinal cord injury

Spinal cord injury (SCI) decreases people's both physical and psychological levels. The rehabilitation of SCI is still a clinical challenging process owing to the inflammatory environment for cell survival. Herein, we designed a dopamine-modified chitosan hydrogel to improve poor microenvironment of spinal cord injury. Dopamine modified chitosan hydrogel was fabricated by crosslinking with citric acid (CS-CA-DA), which address the insufficient mechanical properties. In vitro analysis showed that dopamine modification improved the cell survival and cell adhesion. Moreover, implantation of CS-CA-DA hydrogel alone into rat injured spinal cord helped improving cell survivals, modulating immunity, promoting macrophage polarization to the M2 phenotype and promoting axonal regeneration in vivo in brutal areas of SCI. This strategy of modified chitosan with dopamine undergoing a high mechanical properties, excellent cell compatibility and antioxidant performance, providing a new insight into repairing spinal cord injury.

Evaluation of Physically and/or Chemically Modified Chitosan Hydrogels for Proficient Release of Insoluble Nystatin in Simulated Fluids.

To avoid fungal spreading in the bloodstream and internal organs, many research efforts concentrate on finding appropriate candidiasis treatment from the initial stage. This paper proposes chitosan-based physically or chemically cross-linked hydrogels aimed to provide sustained release of micronized nystatin (NYSm) antifungal drug, known for its large activity spectrum. Nystatin was demonstrated itself to provide hydrodynamic/mechanic stability to the chitosan hydrogel through hydrophobic interactions and H-bonds. For chemical cross-linking of the succinylated chitosan, a non-toxic diepoxy-functionalized siloxane compound was used. The chemical structure and composition of the hydrogels, also their morphology, were evidenced by infrared spectroscopy (FTIR), by energy dispersive X-ray (EDX) analysis and by scanning electron microscopy (SEM), respectively. The hydrogels presented mechanical properties which mimic those of the soft tissues (elastic moduli < 1 MPa), necessary to ensure matrix accommodation and bioadhesion. Maximum swelling capacities were reached by the hydrogels with higher succinic anhydride content at both pH 7.4 (429%) and pH 4.2 (471%), while higher amounts of nystatin released in the simulative immersion media (57% in acidic pH and 51% in pH 7.4) occurred from the physical cross-linked hydrogel. The release mechanism by non-swellable matrix diffusion and the susceptibility of three Candida strains make all the hydrogel formulations effective for NYSm local delivery and for combating fungal infections.

Catechol-modified chitosan hydrogel containing PLGA microspheres loaded with triclosan and chlorhexidine: a sustained-release antibacterial system for urinary catheters

Blockage and infection are common in hospitals, especially with long-term indwelling catheters, due to bacterial adhesion, colonization, and other reasons. A drug-sustained-release antibacterial coating for urinary catheters was described in this paper. Chlorhexidine (CHX) and triclosan (TCS) were encapsulated in poly(lactic-co-glycolic acid) microspheres and mixed with a modified chitosan hydrogel deposited on the surface of silicone rubber. The results showed that drugs can be released continuously more than 35 days. Catechol-modified chitosan (Chi-C) hydrogel was successful synthesized according to FT-IR and UV spectrophotometry, as well as 1H NMR. Furthermore, the coating with CHX and TCS presented stable antibacterial ability compared to the other groups. The results of CCK-8 revealed that the coating was cytotoxic-free and had a wide range of applications. The findings could provide a new drug sustained-release system and hydrogel-microsphere assembly for urinary catheters. Highlights The microspheres presented a sustained release more than 40 days with a remarkable initial burst release. The microspheres/catechol-modified chitosan (Chi-C)/silicon rubber system emerged stable binding ability in liquid environment more than 14 days. The Chi-C/chlorhexidine (CHX)+triclosan (TCS) microspheres system presented better antimicrobial property for entire experiment period. The coated samples showed no significant difference for relative growth rate (RGR) compared to different groups.

Application of Novel Modified Chitosan Hydrogel Composite for the Efficient Removal of Eriochrome Black T and Methylene Blue Dyes from Aqueous Media

Application of Novel Modified Chitosan Hydrogel Composite for the Efficient Removal of Eriochrome Black T and Methylene Blue Dyes from Aqueous Media

Versatile potentiometric metabolite sensing without dioxygen interference

The field of electrochemical biosensors has been dominated by amperometric and voltammetric sensors; however, these are limited greatly in their signal dependence on electrode size. Open circuit potentiometric sensors are emerging as an alternative due to their signal insensitivity to electrode size. Here, we present a second-generation biosensor that uses a modified chitosan hydrogel to entrap a dehydrogenase or other oxidoreductase enzyme of interest. The chitosan is modified with a desired electron mediator such that in the presence of the analyte, the enzyme will oxidize or reduce the mediator, thus altering the measured interfacial potential. Using the above design, we demonstrate a swift screening method for appropriate enzyme-mediator pairs based on open circuit potentiometry, as well as the efficacy of the biosensor design using two dehydrogenase enzymes (FADGDH and ADH) and peroxidase. Using 1,2-naphthoquinone as the mediator for FADGDH, dynamic ranges from 0.1 to 50 mM glucose are achieved. We additionally demonstrate the ease of fabrication and modification, a lifetime of ≥28 days, insensitivity to interferents, miniaturization to the microscale, and sensor efficacy in the presence of the enzyme's natural cofactor. These results forge a foundation for the generalized use of potentiometric biosensors for a wide variety of analytes within biologically-relevant systems where oxygen can be an interferent.

Facile Preparation of Tunicate-Inspired Chitosan Hydrogel Adhesive with Self-Healing and Antibacterial Properties.

In order to replace traditional wound treatments such as sutures, tissue adhesives with strong wet tissue adhesion and biocompatibility have attracted more attention to the applications of non-invasive wound closure. Herein, inspired by tunicate adhesive protein, a series of 2,3,4-trihydroxybenzaldehyde (TBA)-modified chitosan hydrogels (CS-TBA-Fe) were prepared by easily mixing the solutions of chitosan-FeCl3 and TBA via the Schiff-base reaction and the coordination between Fe3+ and pyrogallol groups. The gelation time was greatly shortened to only several seconds after induced even trace Fe3+. The hydrogel (CS-TBA-Fe) exhibited ~12-fold enhanced wet tissue adhesion strength (60.3 kPa) over the commercial fibrin glue. Meanwhile, the hydrogel also showed robust adhesion to various substrates such as wood, PMMA, and aluminum. The swelling ratio and rheological property can be simply controlled by changing the concentrations of chitosan, TBA, and Fe3+. Moreover, the hydrogel displayed a rapid and highly efficient self-healing ability and an excellent antibacterial activity against E. coli. The overall results show that the CS-TBA-Fe hydrogel with enhanced wet adhesiveness will be a promising tissue adhesive material.

Boron Removal by Sorption on Modified Chitosan Hydrogel Beads.

An excess concentration of boron in irrigation and drinking water can negatively affect the yield of plants and the human nervous system, respectively. To meet the recommended levels, hybrid biosorbent hydrogel beads based on chitosan and manganese (II-IV) were employed for the removal of boron from aqueous media. The results showed that the biosorbent effectively removed boric acid from the aqueous medium at neutral pH over a sorption time of 2 h and the liquid/hydrogel ratio of 20 mL/g, achieving a maximum sorption capacity near 190 mg/g. The modeling of the sorption equilibrium data indicated that the Freundlich isotherm equation gave the best fit out of the isotherm models examined. A pseudo-second-order model was found to best describe the sorption kinetics. The favorable attachment of manganese to the chitosan structure enabled the sorption of boron and was confirmed by FTIR, RS, XRD, SEM and ICP-OES methods. Boron desorption from the spent biosorbent was successfully achieved in three cycles using a NaOH solution. In general, the results of this research indicate that this method is one of the possibilities for improving water quality and may contribute to reducing pollution of the aquatic environment.

Dodecenylsuccinic anhydride modified chitosan hydrogels for the sustained delivery of hydrophobic drugs. The case of thymol buccal delivery

AbstractChitosan polymer as a bioactive carrier has an emerging importance due to its great versatility. Many strategies are reported for enhancing its properties. Herein, chitosan hydrogels modified by dodecenylsuccinic anhydride (DDSA) are prepared, characterized by SEM, FTIR, 13C NMR while their mechanical properties and cytotoxicity are assessed. Chitosan modification was studied by FTIR and 13C NMR. According to rheological measurements, modified chitosan hydrogels present a predominantly elastic behavior and exert a higher compressive strength than chitosan hydrogels. Furthermore, this work evaluates thymol incorporation, its release profile as well as its in vivo performance in a periodontitis rat model. In vitro studies reveal that thymol‐loaded‐DDSA‐chitosan hydrogels possess antimicrobial activity against Staphylococcus aureus and Pseudomonas aeruginosa for 2 days and antioxidant activity for 5 days. The incorporation of hydrophobic chains improves thymol release profile; however, DDSA‐chitosan hydrogels cytotoxicity is greater when compared to chitosan hydrogels. Finally, in a preliminary in vivo study, the local application of thymol‐loaded hydrogels is evaluated during a one‐week period. The histomorphometric measurements indicate that periodontal damage is lower when thymol is administrated in chitosan hydrogels in comparison to DDSA‐chitosan hydrogels. Nevertheless, DDSA‐chitosan hydrogels could still be useful for the sustained local delivery of hydrophobic drugs.

Adsorption of Cu2+, Cd2+ and Pb2+ in wastewater by modified chitosan hydrogel

ABSTRACT Heavy metal pollution is extraordinary critical, so it is urgent to develop an effective adsorbent to dispose of such pollution. Modified chitosan was combined with polyacrylic acid to form N-carboxymethyl chitosan hydrogel (NCS-hydrogel) adsorbent. The morphology and structure of NCS-hydrogel were analyzed and identified by infrared spectroscopy, scanning electron microscopy, thermogravimetric analysis and other characterization methods. NCS-hydrogel adsorption was used to treat water pollution of Cu, Cd and Pb ions, and the influencing factors of adsorption performance were studied. The intrinsic mechanism of adsorption process was discussed by thermodynamic, kinetic and isotherm models. The results show that the adsorption process of metal ions by NCS-hydrogel meets the spontaneous monolayer chemisorption, and the adsorption process is accompanied by heat release.

Sustainable antimicrobial modified chitosan and its nanoparticles hydrogels: Synthesis and characterization

The target of the present study is the development of sustainable chitosan and chitosan nanoparticles-based heterocyclic compound hydrogels with antimicrobial properties. Sustainable antimicrobial new modified chitosan hydrogel (CS-3) was synthesized by the reaction of chitosan (CS) with 2-([4-[(1, 3-dioxoisoindolin-2-ylimino) methyl] phenyl] methyleneamino) isoindoline-1, 3-dione (3) via ring opening of cyclic imide moiety in compound (3). However, the modified chitosan nanoparticles hydrogel (CS-3 NPs) were prepared in-situ by an ionotropic gelation technique using sodium tripolyphosphate (TPP) as the cross-linking agent. The prepared hydrogels were characterized by FTIR, SEM, TEM, TGA, DSC and elemental analysis. The hydrogels were tested versus eight pathogenic strains of Gram +ve and Gram −ve bacteria and two fungi. The results revealed that hydrogels (CS-3) and (CS-3 NPs) showed higher antimicrobial activities than virgin (CS) and (CS-NPs). However, hydrogel (CS-3 NPs) showed the highest Minimal Inhibitory Concentration (MIC) and Minimal Bactericidal Concentration (MBC) especially with Gram +ve bacteria (S. pyogenes) at 19.5 and 39 μg/ml compared to the standard antibiotic Ciprofloxacin at 19 and 38 μg/ml respectively.

N-Aminorhodanine modified chitosan hydrogel for antibacterial and copper ions removal from aqueous solutions

A novel adsorbent based on N-Aminorhodanine modified chitosan hydrogel was synthesized and evaluated for antibacterial and copper ions removal from aqueous systems. N-Aminorhodanine was reacted with glutaraldehyde to yield Schiff base followed by reaction with chitosan to obtain the new hydrogel adsorbent. The new adsorbent was analyzed using FTIR, 1H NMR, XRD, TGA, HR-SEM and EDX in addition to the swelling behavior. The maximum adsorption capacities of chitosan and modified chitosan for copper ions were 38 and 62.5 mg/g respectively. The adsorption isotherm belongs Freundlich model and pseudo second order kinetics regime. The adsorption was reach to maximum within 15 min for modified chitosan hydrogel while take about 360 min for chitosan. Regeneration of adsorbent showed only 23% decline after 6 cycles which indicate the stability of the new adsorbent and it can be reused several times with good efficiency. N-Aminorhodanine modified chitosan hydrogel showed good activity towards gram positive bacteria.

A multiscale coarse-grained model to predict the molecular architecture and drug transport properties of modified chitosan hydrogels.

Hydrogels constructed with functionalized polysaccharides are of interest in a multitude of applications, chiefly the design of therapeutic and regenerative formulations. Tailoring the chemical modification of polysaccharide-based hydrogels to achieve specific drug release properties involves the optimization of many tunable parameters, including (i) the type, degree (χ), and pattern of the functional groups, (ii) the water-polymer ratio, and (iii) the drug payload. To guide the design of modified polysaccharide hydrogels for drug release, we have developed a computational toolbox that predicts the structure and physicochemical properties of acylated chitosan chains, and their impact on the transport of drug molecules. Herein, we present a multiscale coarse-grained model to investigate the structure of networks of chitosan chains modified with acetyl, butanoyl, or heptanoyl moieties, as well as the diffusion of drugs doxorubicin (Dox) and gemcitabine (Gem) through the resulting networks. The model predicts the formation of different network structures, in particular the hydrophobically-driven transition from a uniform to a cluster/channel morphology and the formation of fibers of chitin chains. The model also describes the impact of structural and physicochemical properties on drug transport, which was confirmed experimentally by measuring Dox and Gem diffusion through an ensemble of modified chitosan hydrogels.

Infrared imaging of modified chitosan hydrogel film morphology study of polyvinyl alcohol adsorption

The hydrogel film of chitosan with pore structure can be produced by using glutaraldehyde as reaction crosslinking agent to crosslink polyvinyl alcohol and chitosan, which has higher adsorption efficiency. The structure of film is characterized by infrared image, and its morphology is characterized by SEM. The adsorption of acid red 73 under different conditions is primarily studied. The results show that the hydrogel film has a three-dimensional porous microstructure, and the material kinetics is found to effectively absorb acid red 73, with a maximum adsorption amount of 6.5639 mg/g. It is proven as an ideal adsorption material. After studying the thermodynamics of adsorption of the material, △H < 0 was obtained, ∣△H∣ = −81.59861kJ/mol, which belongs to exothermic reaction, primarily reflected as chemical adsorption.

Chitosan nanoparticle hydrogel based sebacoyl moiety with remarkable capability for metal ion removal from aqueous systems

In this present study, a new modified chitosan hydrogel, Cts-SC NPs, was prepared from a one pot reaction of sebacoyl chloride (SC) with chitosan in the presence of 1% v/v glacial acetic acid and 1% w/v sodium tripolyphosphate (TPP) using an ionotropic gelation technique. The modified chitosan hydrogel, Cts-SC NPs, was characterized by FTIR, TEM, XRD, TGA, DSC and SEM. The adsorption efficiency of Cts-SC NPs for metal ions Hg2+, Ni2+ and Co2+ from aqueous solution was evaluated. The effects of various parameters such as contact time, pH and initial metal ions concentration were investigated. Adsorption isotherm data were fitted using different two-parameter models. Modified chitosan hydrogel Cts-SC NPs had remarkable adsorption of Hg2+, Ni2+ and Co2+ ions than chitosan hydrogel Cts-NPs. The antimicrobial activity of Cts-NPs towards the bacteria, Bacillus subtilis, Pseudomonas aeruginosa and fungus Aspergillus flavus was improved by modification with sebacoyl chloride to give Cts-SC NPs.