Chitosan Research Articles

Chitosan-Polyaniline (Bio)Polymer Hybrids by Two Pathways: A Tale of Two Biocomposites.

Previous research highlights the potential of polyaniline-based biocomposites as unique adsorbents for humidity sensors. This study examines several preparative routes for creating polyaniline (PANI) and chitosan (CHT) composites: Type 1-in situ polymerization of aniline with CHT; Type 2-molecular association in acidic aqueous media; and a control, Type 3-physical mixing of PANI and CHT powders (without solvent). The study aims to differentiate the bonding nature (covalent vs. noncovalent) within these composites, which posits that noncovalent composites should exhibit similar physicochemical properties regardless of the preparative route. The results indicate that Type 1 composites display features consistent with covalent and hydrogen bonding, which result in reduced water swelling versus Type 2 and 3 composites. These findings align with spectral and thermogravimetric data, suggesting more compact structure for Type 1 materials. Dye adsorption studies corroborate the unique properties for Type 1 composites, and 1H NMR results confirm the role of covalent bonding for the in situ polymerized samples. The structural stability adopts the following trend: Type 1 (covalent and noncovalent) > Type 2 (possible trace covalent and mainly noncovalent) > Type 3 (noncovalent). Types 2 and 3 are anticipated to differ based on solvent-driven complex formation. This study provides greater understanding of structure-function relationships in PANI-biopolymer composites and highlights the role of CHT as a template that involves variable (non)covalent contributions with PANI, according to the mode of preparation. The formation of composites with tailored bonding modalities will contribute to the design of improved adsorbent materials for environmental remediation to versatile humidity sensor systems.

Fluoride Removal from Aqueous Solutions by Using Super-Adsorbents of Chitosan/Orange Peels/Activated Carbon@MgO: Synthesis, Characterization, and Adsorption Evaluation

Exposure to excessive concentrations of fluoride in potable water is harmful to human health; therefore, its limitation is deemed necessary. Among the commonly applied technologies, adsorption is selected, as it is a highly effective, simple, and economically efficient treatment. In the present study, several combinations of chitosan (CS), orange peels (OP), activated carbon (AC), and MgO were synthesized and tested as adsorbents in order to find the most effective derivative for fluoride extraction. The impact of the adsorbent dosage, pH level, contact time, and initial concentration was investigated to assess the feasibility of the chitosan/orange peels/activated carbon@MgO composite. According to the results, the modification of chitosan with AC, OP, and MgO in a unique adsorbent (CS/OP/AC@MgO), especially in acidic conditions (pH 3.0 ± 0.1) by using 1.0 g/L of the adsorbent, demonstrated the highest efficiency in F removal, up to 97%. The pseudo-second (PSO) order model and Langmuir isotherm model fit better to the experimental results, especially for CS/OP/AC@MgO, providing a Qm = 26.92 mg/g. Thermodynamic analysis confirmed the spontaneous nature of the adsorption process. The structure and morphology of the modified OP/CS@AC-Mg were extensively characterized using BET, XRD, FTIR, and SEM techniques.

Chitosan-based hydrogel dressings with antibacterial and antioxidant for wound healing

Bacterial infection and free radical oxidative stress at the wound site could easily cause cascade inflammation and hinder the healing process of the wound. In this study, chitosan-cysteine-gallic acid (CCG) hydrogel with antibacterial and antioxidant properties was synthesized by chitosan (CS), cysteine (Cys), and gallic acid (GA) for a preliminary evaluation of its therapeutic efficacy in a mouse model of full-layer skin defect. In vitro analysis showed that the CCG hydrogel had good antibacterial activity and blood compatibility. In vivo, the CCG hydrogel wound dressings accelerated wound healing, stimulate angiogenesis, increase collagen deposition and anti-inflammatory factor expression. The CCG hydrogel wound dressing is designed to promote the regeneration of damaged skin tissue and is expected to become a potential candidate for clinical treatment.

Bioactive Curcuma aromatica-stabilized silver nanoparticles embedded chitosan dressing with improved antibacterial, anti-inflammatory, and wound healing properties

Chronic wounds, particularly those infected with multidrug-resistant (MDR) pathogens, present significant challenges for effective healing. Silver nanoparticles (CAAgNPs) were synthsized using aqueous rhizome extract of Curcuma aromatica (CA), known for its wound-healing properties. CAAgNPs were incorporated in a chitosan (CS) dressing (CAAgNPs/CS) and tested for their wound healing potential, expecting synergistic action of AgNPs and phytochemicals capped on it. The porous nature of the CAAgNPs was confirmed using Field emission scanning electron microscopy. Fourier-transform infrared spectroscopy demonstrated a shift in peak intensity from 1589.06 to 1575.54 cm-1 for CAAgNPs/CS dressing confirming crosslinking with glutaraldehyde. Antibacterial activity of the dressings was cofirmed against isolates of Pseudomonas aeruginosa and Staphylococcus aureus. Wound healing studies were carried out using Wistar rats (six groups)- wound control, CS, CAAgNPs256/CS, CAAgNPs512/CS, CAAgNPs1024/CS, and commercial dressings. Histological examination and direct red-80 staining demonstrated maximum epithelization and collagen deposition (58.02%) within CAAgNPs1024/CS groups on day 10. Increased hydroxyproline levels (76.51 µg/mL) on day 7 for CAAgNPs1024/CS indicated maximum collagen formation. Reduced levels of inflammatory cytokines IL-6 (17.38 pg/mL) and TNF-α (80.38 pg/mL) on day 10 indicated quick wound healing without scar formation and damaging effects. The present study highlights the antibacterial and anti-inflammatory properties of CAAgNPs1024/CS dressings with a potential for wound healing applications.

Scientific evaluation on biodegradable and biofunctional polyurethane incorporated chitosan/elastin electrospun membranes in compared with synthetic polymeric expanded polytetrafluoroethylene and polyethylene terephthalate vascular membranes

Cardiovascular disease is a life-threatening health problem. Employing vascular membranes is one of the treatment options in cardiovascular surgery to replace damaged vascular tissues. However, certain limitations associated with synthetic polymeric vascular membranes (expanded polytetrafluoroethylene (e-PTFE) and polyethylene terephthalate (PET)) such as low biodegradability and biofunctional, may lead to thrombosis, inflammatory response, and tissue necrosis. Polyurethane (PU) is commonly applied in vascular engineering, owing to its good biocompatibility and biodegradability. Incorporating chitosan (CS) and elastin (EL) into the PU matrix, specifically in the design of electrospun nanofibrous membrane, is expected to enhance the biological properties of PU. These improvements are crucial to overcome the limitations of synthetic vascular membranes. Previously, there was no scientific comparison between synthetic vascular membranes and the improved design of PU-based nanofibrous membranes. This scientific comparison is pivotal to allow more research exploration on biodegradable and biofunctional materials towards the fabrication of vascular membranes. Herein, the physicochemical, biodegradability, and biofunctional capability of the electrospun PU-based electrospun membranes and two synthetic membranes were compared. Both PU and PU/CS/ES electrospun membranes were annotated with N–H, C–H, and C–N groups with the appearance of elongated fibers. The –CF2 group was presented in the e-PTFE membranes with the view of expanded fibril structure and interconnecting nodes. Whereas for the PET membranes, C=C, C=O, and C–O groups were noticed with the appearance of homogeneous knitted morphology. The PU/CS/ES membranes were found to be more hydrophilic than the PU and the synthetic membranes. The incorporation of CS and EL in the matrix of electrospun PU has improved the PU's biodegradability up to 23.86 ± 5.86 % at 60 days of incubation with the view of swollen and degraded elongated fibers, following the degradation test. Both synthetic polymeric membranes were declared non-biodegradable with less than 7 % degradation at similar incubation timepoint. The PU/CS/ES membranes were also found biofunctional with the most 82 ± 0.49 % of cell viability, protruded cell filopodia, and 44.24 ± 13.99 % scratch cell closure within 24 h of incubation. The incorporation of CS and EL into the PU matrix has improved the biodegradability and biofunctionality compared to the pure PU and synthetic polymeric membranes. Thus, highlight the suitability of PU/CS/ES electrospun membranes to be applied in cardiovascular tissue engineering.

Artificially regulated interphase on natural graphite realizes rapid charge and durable high-temperature cycling of Li-ion batteries

Natural graphite (NG) is a strong competitor in the anode market of Li-ion batteries because of its low cost, rich resource, low energy consumption and low carbon dioxide emission during production. The main problems inhibiting its universal application are its high surface area and the attendant unstable solid/electrolyte interphase (SEI), leading to unsatisfactory cycling and rate performance. In this work, a Li+-conductive, thermally and mechanically stable organic polymer layer is successfully constructed on NG surface by virtue of the simultaneous polymerization and crosslinking reactions of chitosan (CS) and acrylic acid (AA). With controllable thickness, the polymer layer denoted as CSAA significantly decreases the specific surface area of NG, works as an inner SEI substrate greatly mitigating the decomposition of electrolyte, and induces the formation of a LiF-rich SEI outer layer. The SEI resistance and activation energy for charge-transfer reactions are considerably reduced. Benefiting from the superior properties of CSAA-derived SEI, the NG@CSAA anodes exhibit a high initial coulombic efficiency of 94.1 %, fast charge/discharge capability and prolonged cycle life at both 25 °C and 45 °C in the LiFePO4 cathodes-based full cells.

Natural Rubber Films Reinforced with Cellulose and Chitosan Prepared by Latex Aqueous Microdispersion.

In this paper, green composite films comprising natural rubber (NR), cellulose (CE), and chitosan (CS) were successfully fabricated through a simple, facile, cost-effective method in order to improve mechanical, chemical, and antimicrobial properties of NR composite films. Chitosan with a low molecular weight of 30,000-50,000 g/mol (CS-L) and a medium molecular weight of 300,000-500,000 g/mol (CS-M) was used for the fabrication. The composite films were prepared via a latex aqueous microdispersion method with different weight ratios of NR:CE:CS-L/CS-M. Fourier transform infrared spectroscopy (FTIR) results demonstrated strong interactions of hydrogen bonds between CE and CS-L/CS-M in the composite films. The tensile strength and the modulus of the composite films in dried form were found to significantly increase with the reinforcement of CE and CS-L/CS-M. The maximum tensile strength (13.8 MPa) and Young's modulus (12.7 MPa) were obtained from the composite films reinforced with CE at 10 wt.% and CS-L at 10 wt.%. The high elongation of 500-526% was obtained from the composite films reinforced with CE at 10 wt.% and CS (CS-L or CS-M) at 5.0 wt.%. The modification could also significantly promote antimicrobial activities and chemical resistance against non-polar solvents in the composite films. The NR composite films have potential uses as flexible films for sustainable green packaging.

Controlled released dynamics of methotrexate from chitosan-based capsules: A detailed energy landscape analysis

Polymeric membranes are extensively used to construct vehicles for various drug delivery applications. In this study, we investigated the potential of chitosan-based membranes as a carrier for the controlled release of methotrexate (MTX), a widely used drug in cancer treatment. The chitosan (CS) chains were cross-linked with sodium tripolyphosphate (STPP) to form a rigid matrix capable of encapsulating MTX. Molecular dynamics simulations were employed to assess the performance of the CS-based membranes in releasing MTX upon exposure to water. We have calculated the potential of mean force to understand the energy landscape in the aqueous medium or ethanol-water solution. We have observed that the free energy in the ethanol-water solution reduced to ∼52.4 kcal/mol as compared to an aqueous solution. In addition, we have shown the effect of the concentration of STPP on the binding of CS with MTX. Understanding how STPP concentration affects MTX release is crucial for designing drug delivery systems. By adjusting the concentration of STPP, one can fine-tune the release profile of the drug. We have also shown the comparative study of energy requirement to release a drug molecule from the CS matrix with and without STPP molecules. The pair correlation displayed that the water molecules have a stronger interaction with the STPP molecules compared to CS chains and MTX molecules. Our findings indicate that the CS nanoparticles exhibit promising characteristics for controlled drug release, making them a potential candidate for improving the efficacy and safety of MTX therapy in cancer treatment.

Two birds with one stone: A ferrocene-based zirconium(IV)-organic framework nanosheet denoting intrinsic high proton conductivity and acting as a fine dopant to chitosan-based composite membranes

Recently, it was demonstrated that employing metal-organic frameworks (MOFs) with prominent proton conductivity (σ) as fillers with organic substrates such as chitosan (CS) or Nafion is an effective approach for preparing composite membranes (CMs) with outstanding functionalities. Inspired by this, one extremely stable Zr(IV)-MOF (namely Zr-FDC) with a nanosheet structure produced by 1,1′-ferrocene dicarboxylic acid (H2FDA) was successfully manufactured in this research and subsequently used as a filler to synthesize a series of CS-based CMs via casting method. The alternating current (AC) impedance determinations manifested that both Zr-FDC and the related CS-based CMs (CS/MOF-x; x = 2, 4, 6, 8 being the mass percentage of Zr-MOF in the CM) showed ultrahigh σ values, indicating the structural advantages of the Zr-MOF. Further research verified that when the MOF doping quantity is 4 %, the CM's (CS/MOF-4) σ is the greatest, being 2.22 × 10−2 S/cm, which is boosted by nearly tenfold at 100 °C and 98 % relative humidity (RH) compared to the original MOF (3.2 × 10−3 S/cm). Furthermore, the CM exhibits superior thermal stability and tensile resistance. Finally, considering the structural features of the MOF and CS, activation energy data, and other determinations, we thoroughly theorized the proton conduction process within the MOF framework and CMs, referencing the subsequent proton exchange membrane design.

Preparation of chitosan-based macromolecular antioxidant with high-efficiency free radical scavenging ability to improve the antioxidative properties of styrene-butadiene rubber/silica composites

To address the disadvantages of traditional rubber antioxidants with low molecular weight such as easy migration, poor extraction resistance, low thermal stability and antioxidant efficiency, in this work, we first prepared an antioxidant containing primary and secondary antioxidant groups (MC-MPA) through thiol-ene click reaction between N-(4-aminophenyl)maleimide (MC) and 3-mercaptopropionic acid (MPA). Then, we synthesized a chitosan-based macromolecular antioxidant with long-chain alkene, aromatic secondary amine, and thioether groups (COS-UC-MC-MPA) by sequentially grafting functional compounds 10-undecanonyl chloride (UC) and antioxidant MC-MPA onto natural macromolecular polymer chitosan (COS). The free radical scavenging ability of COS-UC-MC-MPA was assessed by using 2,2-Diphenyl-1-picrylhydrazyl (DPPH), and the results demonstrated that COS-OC-MC-MPA has high scavenging rate of 76.5 % for DPPH free radicals after 1 min of contact with DPPH dimethyl sulfoxide solution, showing excellent free radical scavenging ability. In addition, the results of accelerated thermo-oxidative aging test, thermogravimetric (TG) test, kinetic analysis of thermal-oxidative degradation, extraction resistance test, and volatilization resistance test indicated that COS-UC-MC-MPA with superior migration resistance and volatilization resistance could effectively enhance the antioxidative properties, thermal stability and thermal-oxidative stability of rubber composites. Moreover, the results of rubber processibility analysis (RPA) test and scanning electron microscopy (SEM) implied that the addition of COS-UC-MC-MPA is also conductive to improving the dispersibility of silica in rubber matrix. This study supplies a new perspective for the preparation of environmentally friendly and highly efficient macromolecular antioxidants for rubber composites.

Development of graphene oxide and magnesia immobilized kaolin supported dual biopolymeric hybrid material for methyl orange and malachite green removal from water

Industrial usage of various dyes seriously depends on the efficient treatment of industrial effluents. Efficient retention of waste matter using a variety of adsorbent materials has as a result turned into dangerous. In this research article, graphene oxide (GO) cum magnesium oxide (MgO) impregnated kaolin (KA) based chitosan (CS) and pectin (Pect) composite namely GO/MgO/KA/CS-Pect as an adsorbent material for effective methyl orange (MO) and malachite green (MG) removal in aquatic system. The physico-chemical properties like bonding, structural morphology and elemental composition of GO/MgO/KA/CS-Pect were explored with numerous sophisticated instrumental techniques viz., FTIR, SEM, XRD, EDAX and elemental mapping analysis. The influencing parameters of adsorption method, with effect of reaction time, solution pH, dosage, pHzpc, initial MO/MG concentration and temperature were investigated for MO and MG removal under batch scale. The removal of MO and MG rate of the GO/MgO/KA/CS-Pect was incredibly fast and the adsorption kinetic method was driven with intraparticle diffusion (IPD) and pseudo-second-order (PSO) kinetic models. The adsorption isotherm strongly well-adapted with Langmuir isotherm and the maximum removal efficiency of GO/MgO/KA/CS-Pect was found to be 45.50 and 42.00 mg/g for MO and MG respectively within 40 min. The MO and MG uptake by GO/MgO/KA/CS-Pect was majorly owing to chemical adsorption namely electrostatic adsorption, hydrogen bonding and π-π interaction mechanism. The prepared GO/MgO/KA/CS-Pect was productively regenerated with absolute ethanol and could be repetitively reused. This exploration reveals the feasibility and selectivity of the GO/MgO/KA/CS-Pect as genuine adsorbent material for removal of MO and MG from the aquatic system.

Advanced absorption-storage water molecules strategy reinforces antifouling property for stable oil/water emulsions separation

Constructing membranes with extraordinary resistance to oil contamination under high permeation flux is a considerable challenge. Herein, an advanced absorption-storage water molecules strategy is proposed for constructing the robust hydration layers to achieve effective anti-oil fouling and stable oily wastewater purification. Specifically, metal–organic framework (MOF, UiO-66-NH2) nanoparticles with powerful water-absorbing characteristics are preferentially adsorbed to collect water in oil/surfactant/water systems. Combining excellent water retention, the micro-/ nano-networks formed by attapulgite (APT) could store the water molecules captured by MOF. The synergistic effect of the water-absorbing/water-retaining interactions between the MOF and APT created robust hydration layers defense barriers, which enhanced the resistance of membrane to oil contamination. Furthermore, the abundant hydrophilic groups (e.g., –OH, –NH2 and –CONH2) of chitosan (CS) further improved the membrane surface hydrophilic coverage, permeability and hydration ability. As a result, the developed CS/APT@MOF composite membrane exhibited significant anti-oil fouling capability and realized superior purification property towards various oil-in-water emulsions stabilized by surfactants. The CS/APT@MOF composite membrane demonstrated outstanding oil repellency (flux recovery ratio > 99.6 %, total flux decline ratio < 3.8 %) over 10 cycles under large permeability (>660 L m-2h−1 bar−1). Meanwhile, the constructed CS/APT@MOF composite membrane exhibited stable separation cycle capability (10 cycles) and continuous purification performance (60 min) for different oil/water emulsions. Therefore, this advanced strategy based on absorption-storage water molecules to construct robust hydration layers provides a promising insight for the development of superior antifouling and operationally stable oil/water emulsions separation membranes.

Chitosan-ginger essential oil nanoemulsions loaded gelatin films: A biodegradable material for food preservation

The alarming issue of food waste, coupled with the potential risks posed by petroleum-based plastic preservation materials to both the environment and human health necessitate innovative solutions. In this study, we prepared nanoemulsions (NEs) of chitosan (CS) and ginger essential oil (GEO) and systematically evaluated the effects of varying NEs concentrations (0, 10 %, 30 %, 50 %) on the physicochemical properties and biological activities of gelatin films. These films were subsequently applied to blueberry preservation. The scanning electron microscopy confirmed that the NEs were well-integrated with the Gel matrix, significantly enhancing the performance of the Gel films, including improvements of mechanical properties (tensile strength from 7.71 to 19.92 MPa; elongation at break from 38.55 to 113.65 %), thermal, and barrier properties (water vapor permeability from 1.52 × 10−9 to 6.54 × 10−10 g·m/Pa·s·m2). The films exhibited notable antibacterial and antioxidant activities due to the gradual release of GEO, thereby extending the storage life of blueberries. Moreover, the prepared composite films demonstrated excellent biodegradability and environmental friendliness, with the majority of the material decomposing within 30 days under soil microbial action. In conclusion, the active films loaded with NEs exhibit superior performance and hold significant potential for developing biodegradable materials for food preservation.

Innovative double-layer coated stent for enhanced Sca-1+ stem cell recruitment and vascular repair

Abundant stem cells express the stem cell antigen 1 (Sca-1) in bone marrow and vascular adventitia possess the capacity to differentiate into endothelial cells (VECs) and vascular smooth muscle cells (VSMCs) during vascular injury, thus enabling restoration. Dickkopf-3 (Dkk3) and histone deacetylase 7 derived-peptide (7A peptide, MHSPGAD) could increase migration and differentiation of Sca-1+ cells to participate in vascular repair. Herein, we present a double-layered drug coating 316L stainless steel stent (DAC stent) using an ultrasound spray system, which consists of an inner layer of chitosan (CS) loaded with Dkk3 and an outer layer loaded with 7A peptide. The coating exhibits good biocompatibility based on platelet adhesion, water contact angle, cell proliferation, and hemolysis rate experiments. The analysis of VECs and VSMCs on the coating reveals that Sca-1+ cells promote VECs repair and maintain the contractile VSMCs. Further analysis of DAC stent implantation on neointimal inflammation, endothelium repair and vascular remodeling in 3 months shows the coating recruits Sca-1+ cells to the injury sites to differentiate into VECs and contractile VSMCs, thus accelerating vascular repair. A novel stem cell recruiting, chemical-free drug coating stent is developed, and it might be a candidate strategy and promising application prospect for implantation devices.

Chitosan thin films developed with germanium oxide for wound healing applications: Cell viability, wettability, and antibacterial activity

Tailoring a biomaterial with versatile properties is important to develop a multifunctional scaffold for biomedical applications. In this work, chitosan (CS) is chosen to be the matrix material of the scaffold, while hydroxyapatite and germanium dioxide which are encapsulated in CS film enhanced the biological properties. The addition of the dopant increased the hydrophilicity of CS and the chemical reaction on the surface of the scaffold, which supports the adhesion of the scaffold on the skin and cell migration. On the other hand, the TGA showed good thermal stability as about 24.4 % of the scaffold remained at 600 °C. Furthermore, S1 exhibited the most effective antibacterial activity against Bacillus subtilis and Escherichia coli, with an average inhibition zone of 12.5 mm and a low standard deviation of 0.5 mm. S4 demonstrated significant effectiveness against Pseudomonas aeruginosa, with an average inhibition zone of 12.5 ± 0.5 mm. These data indicate that the materials have potential antibacterial capabilities, specifically against Bacillus subtilis and Escherichia coli. Overall, the results indicate that the modified CS scaffold can be utilized in biomedical applications including wound healing.

An advanced ultrasound-activated drug delivery system with piezocatalytic MoS2 nanoflowers for treating patent ductus arteriosus

Patent ductus arteriosus (PDA) is a prevalent cardiovascular anomaly that leads to considerable morbidity and mortality in premature infants. Although pharmacological interventions are commonly used for treatment, they often have notable adverse effects. This study introduces an innovative approach: a controlled drug delivery system that utilizes piezocatalyst nanocarriers produced through hydrothermal techniques. The synthesized nanoparticles undergo thorough characterization to assess their structural and morphological properties. Through ultrasound treatment, precise drug loading and efficient release of indomethacin (IDM) from chitosan (CS) stabilized molybdenum disulfide nanoflowers (MoS2-CS-IDM) are achieved. By harnessing ultrasound-induced reactive oxygen species, this method enables targeted drug delivery. Importantly, the nanoparticles demonstrate an approximately 60 % decrease in PGE2 concentrations, indicating their potential as anti-inflammatory agents. The favorable interaction of the nanoparticles with rat aortic smooth muscle cells and the successful closure of the ductus arteriosus in fetal Wistar rats validate their therapeutic effectiveness in vivo. In conclusion, the piezocatalyst-based drug delivery system presented in this study holds promise for versatile, biocompatible, and controlled drug release, with significant implications for therapeutic applications in PDA and potentially beyond.

On-demand release of CO in dual-responsive nanocomposite hydrogels for wound dressing

Gaseous signaling molecules, especially carbon monoxide (CO), hold promising potential for disease management. The therapeutic efficacy of CO is closely tied to its concentration, however, maintaining it at optimal levels for both efficacy and safety is highly challenging. To address this, we designed a dual-responsive (pH/red light) nanocomposite hydrogel for on-demand CO release. We first synthesized a hybrid nanocomposite (CaCO3@AgCCN) comprising a CO2 donor (CaCO3) and a photocatalyst (Ag3PO4-decorated carbon dot g-C3N4, AgCCN) capable of converting CO2 to CO. The size of CaCO3 particles was approximately 40 nm, while that of AgCCN was around 150 nm in this nanocomposite. CaCO3@AgCCN was then incorporated into chitosan (CS) to form a nanocomposite hydrogel. This nanocomposite hydrogel could respond to a mildly acidic environment due to bacterial growth, generating CO2 exactly where it is needed (the wound site), which would be subsequently catalytically converted to CO by AgCCN under 630-nm red light illumination to facilitate wound healing. The generated CO, readily controlled by adjusting the CaCO3@AgCCN content in the nanocomposite hydrogel and the red-light illumination time (the CO concentration reaching 4.7 μM after 10-min illumination), has demonstrated strong bactericidal and anti-inflammatory effects, both essential in facilitating wound healing as shown in both in vitro and in vivo studies. Coupled with satisfactory biocompatibility, this dual-responsive nanocomposite hydrogel appears to hold great promise for safe and effective applications of CO in biomedical fields.

Engineering Two-dimensional tungsten-doped molybdenum selenide transformed conformational nanoarchitectonics: Trimodal therapeutic nanoagents for enhanced synergistic Photothermal/Chemodynamic/Chemotherapy of breast carcinoma

Two-dimensional transition metal dichalcogenides (TMDCs) exhibit promising photothermal therapy (PTT) and chemodynamic therapy (CDT) for anti-tumour treatment. Herein, we proposed an engineering strategy to regulate the lattice structure of tungsten-doped molybdenum selenide (MoxW1−xSe2) transformed conformational nanoarchitectonics using a microwave-assisted solvothermal method for enhancing peroxidase (POD)-like catalytic performance by adjusting the ratio of molybdenum (Mo) and tungsten (W). Furthermore, the optimised Mo0.8W0.2Se2 nanoflakes surface was modified with chitosan (CHI) for improved biocompatibility and nanocatalytic efficacy, then the obtained CHI-Mo0.8W0.2Se2 subsequently loaded the chemotherapeutic drug mitoxantrone (MTO) for enhanced 4 T1 cells killing ability, shortly denoted as CHI-Mo0.8W0.2Se2-MTO for PTT-augmented CDT and chemotherapy (CT). A series of performance validations successfully showed that electrons tend to transfer from W to Mo in CHI-Mo0.8W0.2Se2, which resulted in superior POD-like activity (Km = 0.038 mM) of CHI-Mo0.8W0.2Se2 compared with that of horseradish peroxidase. Furthermore, CHI-Mo0.8W0.2Se2-MTO with excellent photothermal conversion efficiency (PCE=63.2 %) in the near-infrared (NIR) region could further promote endogenous •OH generation and MTO controlled release within solid tumours. In vivo studies confirmed the successful achievement of synergistic therapeutic effects (tumour inhibition rate of over 90 %) with minimised side effects. Versatile therapeutic nanoagents hold great potential for personalised therapy of breast cancer and will find their way to the pharmaceutical field.

Assembly of Chitosan/Caragana Fibers to Construct an Underwater Superelastic 2D Layer-Supported 3D Architecture for Rapid Congo Red Removal.

Developing environmentally friendly bulk materials capable of easily and thoroughly removing trace amounts of dye pollutants from water to rapidly obtain clean water has always been a goal pursued by researchers. Herein, a green material with a 3D architecture and with strong underwater rebounding and fatigue resistance ability was prepared by means of the assembly of biopolymer chitosan (CS) and natural caraganate fibers (CKFs) under freezing conditions. The CKFs can randomly and uniformly distribute in the lamellar structure formed during the freezing process of CS and CKFs, playing a role similar to that of "steel bars" in concrete, thus providing longitudinal support for the 3D-architecture material. The 2D layers formed by CS and CKFs as the main basic units can provide the material with a higher strength. The 3D-architecture material can bear the compressive force of a weight underwater for multiple cycles, meeting the requirements for water purification. The underwater compression test shows that the 3D-architecture material can quickly rebound to its original shape after removing the stress. This 3D-architecture material can be used to purify dye-containing water. When its dosage is 3 g/L, the material can remove 99.65% of the Congo Red (CR) in a 50 mg/L dye solution. The adsorption performance of the 3D architecture adsorbent for CR removal in actual water samples (i.e., tap water, seawater) is superior than that of commercial activated carbon. Due to its porous block characteristics, this material can be used for the continuous and efficient treatment of wastewater containing trace amounts of CR dye to obtain pure clean water, meaning that it has great potential for the effective purification of dye wastewater.

Encapsulation of Inositol Hexakisphosphate with Chitosan via Gelation to Facilitate Cellular Delivery and Programmed Cell Death in Human Breast Cancer Cells.

Inositol hexakisphosphate (InsP6) is the most abundant inositol polyphosphate both in plant and animal cells. Exogenous InsP6 is known to inhibit cell proliferation and induce apoptosis in cancerous cells. However, cellular entry of exogenous InsP6 is hindered due to the presence of highly negative charge on this molecule. Therefore, to enhance the cellular delivery of InsP6 in cancerous cells, InsP6 was encapsulated by chitosan (CS), a natural polysaccharide, via the ionic gelation method. Our hypothesis is that encapsulated InsP6 will enter the cell more efficiently to trigger its apoptotic effects. The incorporation of InsP6 into CS was optimized by varying the ratios of the two and confirmed by InsP6 analysis via polyacrylamide gel electrophoresis (PAGE) and atomic absorption spectrophotometry (AAS). The complex was further characterized by Scanning Electron Microscopy (SEM) and Fourier Transform Infrared Spectroscopy (FTIR) for physicochemical changes. The data indicated morphological changes and changes in the spectral properties of the complex upon encapsulation. The encapsulated InsP6 enters human breast cancer MCF-7 cells more efficiently than free InsP6 and triggers apoptosis via a mechanism involving the production of reactive oxygen species (ROS). This work has potential for developing cancer therapeutic applications utilizing natural compounds that are likely to overcome the severe toxic effects associated with synthetic chemotherapeutic drugs.