Immunostimulatory eff ect of quaternary degree and acetyl group of quaternized chitosan on macrophages RAW 264.7

Hydroxypropyltrimethyl ammonium chloride chitosan(HACC)and hydroxypropyltrimethyl ammonium chloride fully deacetylated chitosan(De-HACC)were synthesized with various degrees of substitution by altering the ratio of chitosan to glycidyl trimethyl-ammonium chloride(GTMAC).The effects of the quaternary ammonium degree and the acetyl group of these polymers on immunostimulatory activities were detected in RAW 264.7 cells.The expression levels of nitrogen oxide(NO),interleukin-6(IL-6)and tumor necrosis factor(TNF-α)were compared.Results show that the removal of acetyl groups in chitosan obviously improved the degree of substitution of quaternary ammonium salts.In addition,HACC and De-HACC were capable of promoting immunological activity in a substitution-dependent manner;HACC was positively correlated,and De-HACC was negatively correlated.Among tested ratios,HACC-30%and De-HACC-54%performed better than the others,and De-HACC-54%performed the best.Generally,quaternized chitosan possesses immunostimulatory activity,which is related to the degree of quaternization and the acetyl group.

Preparation and antibacterial properties of polycaprolactone/quaternized chitosan blends

This article is a preliminary study on antibacterial blends of polycaprolactone,chitosan and quaternized chitosan by melt processing.Blends were characterized,mechanical test and antibacterial evaluation against Escherichia coli and Staphylococcus aureus,were conducted.Results showed that the antibacterial potential of chitosan was limited in blends and polycaprolactone/chitosan did not show significant antibacterial effect compared with neat polycaprolactone(PCL).Inhibition rates of polycaprolactone/quaternized chitosan were 39.2%99.9%against Escherichia coli,while inhibition rate was 40.9%99.9%against Staphylococcus aureus.When quaternized chitosan(QCTS)content was up to 20%,blends exhibited 99.9%inhibition rates against both two types of bacteria.

The Adsorption Effect of Quaternized Chitosan Derivatives on Bile Acid

Three quatemized chitosan derivatives were synthesized and their adsorption performance of bile acid from aqueous solution was studied. The adsorption capacities and rates of bile acid onto quatemized chitosan derivatives were evaluated. The kinetic experimental data properly correlated with the second-order kinetic model, which indicated that the chemical sorption is the rate-limiting step. The results showed that the quatemized chitosan derivatives are favorable adsorbents for bile acid.

Facile fabrication of quaternized chitosan-incorporated biomolecular patches for non-compressive haemostasis and wound healing

Cell-free wound dressings (WDs) with desirable effectiveness and safety have received much attention in the field of regenerative medicine. However, the weak linkages between bioactive polymers and the spatial structure of WDs frequently result in interventional treatment failure. Herein, we create a series of quaternized chitosan (QCS)-incorporated composite hydrogels (referred to as GHCH-n) by UV cross-linking and then convert them into microneedle patches (MNPs). QCS, which is positively charged and amphiphilic, is essential for broad-spectrum antibacterial and haemostatic activities. QCS is proven to be slightly toxic, so it is immobilized into the methacrylate gelatine (GelMA) molecular cage to minimize adverse effects. A polydimethylsiloxane micro-mould is used to shape the MNPs. MNPs can pierce tissue, seal off bleeding sites, and cling to wounds securely. Thus, MNPs can cooperate with GHCH-n hydrogels to halt bleeding and accelerate wound healing. This study recommends GHCH-10 MNPs as an advanced biomaterial. Several preclinical research models have thoroughly validated the application effect of GHCH-10 MNPs. This research also proposes a novel strategy for integrating the nature of bioactive polymers and the structure of composite biomaterials. This strategy is not only applicable to the fabrication of next-generation WDs but also shows great potential in expanding interdisciplinary domains.

Quaternized chitosan-assisted in situ synthesized CuS/cellulose nanofibers conductive paper for flexible electrode

Cellulose nanofibers(CNF)are considered to be a potential substrate of energy material for energy storage devices due to the foldable,lightweight,recyclable and environmentally friendly feature.However,the energy materials tend to distribute unevenly or fall off from CNF easily,resulting in the decrease of the devices’overall performance.Here,for the first time,we used quaternized chitosan(QCS)as stabilizer and adhesive to in situ synthesize and deposite copper sulfide nanocrystals(CuS-NCs)on CNF and further obtained the conductive paper for flexible supercapacitors.In the presence of QCS,CuS-NCs deposited in situ on CNF can be capped and stabilized by the QCS molecular chains for uniform distribution,which is conducive to the capacitive behavior and electrochemical stability of composite paper.The result shows that the specific capacitance of the composite paper was as high as 314.3 F/g at a current density of 1 A/g,a high rate capacitance of 252.6 F/g was achieved even at a high current density of 10 A/g.It reveals that the composite paper exhibited better electrochemical performance than many other CuS-based electrode materials for supercapacitor.More importantly,the composite paper performed well in various folding state without changing much electrochemical performance.Therefore,this work provides a novel strategy to in situ fabricate paper-based electrode for nextgeneration flexible energy-storage system.

Biocompatible and antibacterial soy protein isolate/quaternized chitosan composite sponges for acute upper gastrointestinal hemostasis

Innovative biomedical applications have high requirements for biomedical materials.Herein,a series of biocompatible,antibacterial and hemostatic sponges were successfully fabricated for the treatment of acute upper gastrointestinal bleeding(AUGB).Quaternized chitosan(QC)and soy protein isolate(SPI)were chemically cross-linked to obtain porous SPI/QC sponges(named SQS-n,with n¼30,40,50 or 60 corresponding to the weight percentage of the QC content).The chemical composition,physical properties and biological activity of SQS-n were investigated.SQS-n could support the adhesion and proliferation of L929 cells while triggering no obvious blood toxicity.Meanwhile,SQS-n exhibited good broad-spectrum antibacterial activity against both grampositive bacteria(Staphylococcus aureus)and gram-negative bacteria(Escherichia coli).The in vivo hemostatic effect of SQS-n was evaluated using three different bleeding models.The results revealed that SQS-50 performed best in reducing blood loss and hemostatic time.The overall hemostatic effect of SQS-50 was comparable to that of a commercial gelatin sponge.The enhanced antibacterial and hemostatic activities of SQS-n were mainly attributed to the QC component.In conclusion,this work developed a QC-functionalized hemostatic sponge that is highly desirable for innovative biomedical applications,such as AUGB.

De novo strategy with engineering a multifunctional bacterial cellulose-based dressing for rapid healing of infected wounds

The treatment and healing of infected skin lesions is one of the major challenges in surgery.To solve this problem,collagen I(Col-I)and the antibacterial agent hydroxypropyltrimethyl ammonium chloride chitosan(HACC)were composited into the bacterial cellulose(BC)three-dimensional network structure by a novel membrane-liquid interface(MLI)culture,and a Col-I/HACC/BC(CHBC)multifunctional dressing was designed.The water absorption rate and water vapor transmission rate of the obtained CHBC dressing were 35.78±2.45 g/g and 3084±56 g m^(-2)⋅day^(-1),respectively.The water retention of the CHBC dressing was significantly improved compared with the BC caused by the introduced Col-I and HACC.In vitro results indicated that the combined advantages of HACC and Col-I confer on CHBC dressings not only have outstanding antibacterial properties against Staphylococcus aureus(S.aureus)compared with BC and CBC,but also exhibit better cytocompatibility than BC and HBC to promote the proliferation and spread of NIH3T3 cells and HUVECs.Most importantly,the results of in vivo animal tests demonstrated that the CHBC dressings fully promoted wound healing for 8 days and exhibited shorter healing times,especially in the case of wound infection.Excellent skin regeneration effects and higher expression levels of collagen during infection were also shown in the CHBC group.We believe that CHBC composites with favorable multifunctionality have potential applications as wound dressings to treat infected wounds.

Dihydromyricetin‑Incorporated Multilayer Nanofibers Accelerate Chronic Wound Healing by Remodeling the Harsh Wound Microenvironment

The harsh microenvironment in wound(HMW)remains a major obstacle to chronic wound healing.Although a series of bioactive materials have been developed,few of them are multi-functional and able to accelerate wound healing via precisely remodeling the HMW.Herein,a series of dihydromyricetin(DHM)-incorporated multilayer nanofibers(termed DQHP-n,n=0,2,6 and 10)are fabricated using a layer-by-layer(LBL)self-assembly technique.The average diameters of DQHP-n significantly increase from 0.30±0.16μm to 0.84±0.28μm(P<0.05)along with the n value increased from 0 to 10,the tensile strength of that is also significantly improved from 1.12±0.15 MPa to 2.16±0.30 MPa(P<0.05),and the water contact angle of that significantly decreases from 129.1±1.5°to 76.6±3.9°(P<0.05).The DQHP-n are found to be biocompatible,in which DQHP-6 promoted cell migration through activation of the epithelial–mesenchymal transformation(EMT)pathway and reconstruction of the HMW by stopping bleeding,killing bacteria,eliminating inflammation,and scavenging reactive oxygen species(ROS).The in vivo evaluation is carried out via an E.coli-infected rat skin regeneration model.The DQHP-6 group demonstrates the best effect,as it healed up to 98.5±1.0%of the wound area at day 15.DQHP-6 differentially regulates the mRNA expressions of several cytokines(FGF2,PDGF,IL-1α,IL-6,IL10,and TGF-β),which ends to reductions of total inflammatory cells(CD45^(+) cells)and M1 macrophages(CD80^(+) and CD86^(+) cells),proliferation of host cell(Ki67^(+) cells),and enhancement of collagen synthesis.In conclusion,DQHP-6 exhibits multifunctional properties for HMW,and can serve as a promising wound dressing for clinical transformation.