Environmental Dyeing and Functionalization of Silk Fabrics with Natural Dye Extracted from Lac.

Most traditional synthetic dyes and functional reagents used in silk fabrics are not biodegradable and lack green environmental protection. Natural dyes have attracted more and more attention because of their coloring, functionalization effects, and environmental benefits. In this study, natural dyes were extracted from lac and used for coloring and functionalization in silk fabrics without any other harmful dyes. The extraction conditions were studied and analyzed by the univariate method. The optimal extraction process was that the volume ratio of ethanol to water was 60:40 with a solid-liquid ratio of 1:10, and reacting under the neutrality condition for 1 h at 70 °C. Silk fabric can be dyed dark owing to the certain lifting property of lac. After being dyed by Al3+ post-medium, the levels of the washing fastness, light fastness, and friction fastness of silk fabric are all above four with excellent fastness. The results show that the dyed silk fabrics have good UV protection, antioxidation, and antibacterial properties. The UV protection coefficient UPF is 42.68, the antioxidant property is 98.57%, and the antibacterial property can reach more than 80%. Therefore, the dyeing and functionalization of silk fabrics by utilizing naturally lac dyes show broad prospects in terms of the application of green sustainable dyeing and functionalization.

Development of anti-bacterial adhesion and antibacterial sulfobetaines modified chitosan/polyvinyl alcohol composite films as packaging materials.

Chitosan exhibits a wide source, non-toxic and biodegradable, and is the optimal functional raw material for preparing food packaging materials. However, the pure chitosan film has some disadvantages such as limited antibacterial activity and weak mechanical properties. In this study, sulfobetaines modified chitosan (CS-SBMA) was synthesized by grafting copolymerized betaine methacrylate sulfonate onto the chain of chitosan to improve the anti-bacterial adhesion and antibacterial properties of chitosan, aiming to develop antibacterial and anti-bacterial adhesion films based on CS-SBMA and polyvinyl alcohol (PVA) by the casting method. The structure of CS-SBMA was characterized by 1H NMR and FTIR. The appropriate proportion of CS-SBMA/PVA was determined to be 1/1 and 1/2, by characterizing the composite films with FTIR, XRD, SEM, mechanical, optical, and water resistance behaviors. In addition, CS-SBMA/PVA films showed excellent antibacterial, anti-bacterial adhesion and biofilm control function. The colonies number of E. coli and S. aureus on the surface of CS-SBMA/PVA 1/1 film decreased 94.15 % and 94.27 %, respectively, and 92.93 % of S. aureus and 94.87 % of E. coli colonies were inactivated within 60 min contact. These results indicate that CS-SBMA/PVA film exhibits potential antibacterial and anti-bacterial adhesion properties, which is suitable for food packaging materials.

Functional chitosan/glycidyl methacrylate-based cryogels for efficient removal of cationic and anionic dyes and antibacterial applications.

In this study, we constructed a novel family of chitosan-based cryogels with antibacterial activity to treat different types of dye wastewater. Glycidyl methacrylate (GMA) cross-linked chitosan (CS) cryogels functionalized with negatively and positively molecules were prepared via thermo-crosslinking and freeze-drying methods. These chitosan-based cryogels present a well-defined three-dimensional microporous network structure with ultra-light and high porosity, and have high water absorption ability. For CS/GMA/SMA cryogels, 71.20% of Cationic Yellow X-8GL (CY) can be removed, and the process kinetics well corresponded to the Pseudo-second order model and Freundlich model. The quantity and percent of Reactive Yellow B-4RFN (RY) removal by CS/GMA/DMC cryogel reached at 224.6 mg/g and 96.11%, which closely fitted the Pseudo-second order model and Dubinin-Radushkevich isotherm. Furthermore, the chitosan-based cryogels showed antibacterial efficacies against E. coli and S. aureus. The prepared chitosan-based cryogels with adsorption and antibacterial properties have great potential for the remediation of dyeing wastewater.

Development of Inherently Antibacterial, Biodegradable, and Biologically Active Chitosan/Pseudo-Protein Hybrid Hydrogels as Biofunctional Wound Dressings.

Developing a new family of hydrogel-based wound dressings that could have a dual biofunctionality of antibacterial and biological responses is highly desirable. In this study, an inherently effective antibacterial and biodegradable hydrogel dressing without the need for impregnated antibiotics was designed, synthesized, characterized, and examined for its effect on macrophages, which initiated inflammatory activity and activated both NO and TNF-α production for the purpose of achieving a better and faster wound healing. The purposes of this research was to develop a novel family of cationic biodegradable hydrogels based on arginine-based poly(ester urea urethane) (Arg-PEUU) and glycidyl methacrylate-modified chitosan (CS-GMA) that has both inherent antibacterial and bioactive functionality as a wound healing dressing for accelerated healing of contaminated or infected wounds. These hybrid hydrogels present a well-defined three-dimensional microporous network structure and have a high water absorption ability, and their biodegradation is effectively accelerated in the presence of lysozymes. The hemolytic activity test, MTT assay, and live/dead assay of these hybrid hydrogels indicated that they had no cytotoxicity toward red blood cells, NIH-3T3 fibroblast cells, and human vascular endothelial cells, thus corroborating their cytocompatibility. Furthermore, these hybrid hydrogels could elevate the release of both produced NO and TNF-α by stimulating and activating RAW 264.7 macrophages, augmenting their antibacterial biological response. The antibacterial assay of these hybrid hydrogels demonstrated their excellent antibacterial activity without the need for impregnated antibacterial agents. Taken together, this new family of biodegradable, antibacterial, and biologically responsive hybrid hydrogels exhibits great potential as biofunctional antibacterial wound dressing candidates for wound healing.

Construction of aerogels based on nanocrystalline cellulose and chitosan for high efficient oil/water separation and water disinfection.

The aim of this study was to develop novel aerogels based on nanocrystalline cellulose (NCC), and chitosan (CS) for oily wastewater treatment. The quaternarized N-halamine siloxane monomer (QHS) was successfully synthesized and hydrolyzed to form quaternarized N-halamine siloxane polymer (PQHS) in the mixture of NCC and CS solution to improve the antibacterial properties of aerogels. The strong hydrophilicity of natural polymers NCC and CS and the microporous structure of aerogel endow the underwater oleophobic property. The applications of the aerogels as filter materials for oil/water separation are studied, and showed high separation efficiency of different types of oil/water mixtures. The presence of N-halamine structures in PQHS makes the aerogels effectively kill bacteria in oily sewage and inhibit the growth of bacteria on the surface of the materials. The properties of exceptional reusability, oil/water separation efficiency, and antibacterial efficacies render the aerogels as promising materials with potential applications in oily wastewater treatment.

Novel quaternarized N-halamine chitosan and polyvinyl alcohol nanofibrous membranes as hemostatic materials with excellent antibacterial properties.

The aim of this study was to develop novel nanofibrous membranes based on the quaternary ammonium N-halamine chitosan (CSENDMH) and polyvinyl alcohol (PVA) for antibacterial and hemostasis wound dressing. To improve the antimicrobial properties of nanofibrous membranes, a new chitosan-quaternary ammonium N-halamine derivative was successfully synthesized, and the structure was analyzed by 1H NMR and 13C NMR, fourier transform infrared (FTIR) spectroscopy, and elemental analysis. The morphological and water absorption ability studies showed that the membrane had a uniform bead-free network and high porosity structure like natural extracellular matrix as well as high hydrophilicity. For in vitro evaluation of the hemostatic effect, the membranes showed excellent blood clotting capacity, especially the PVA/CSENDMH membranes. The antimicrobial assay demonstrated excellent antibacterial activity of nanofibrous membranes against both gram-negative and gram-positive bacteria. Furthermore, the cytocompatibility assay results indicated that human fibroblasts could adhere and proliferate on the membranes, thus corroborating their biocompatibility.

Tailored synthesis of polymer-brush-grafted mesoporous silicas with N-halamine and quaternary ammonium groups for antimicrobial applications.

Antimicrobial mesoporous materials with polymer brushes on the surface were prepared, and their structure and antimicrobial performance investigated. Poly ((3-acrylamidopropyl) trimethylammonium chloride) (PAPTMAC) modified mesoporous silica was prepared by a polymer-brush-grafted method through treatment with the initiator 4,4'-azobis (4-cyanovaleric acid) (ACVA) and polymerized with (3-acrylamidopropyl) trimethylammonium chloride (APTMAC). A covalent bond was formed between mesoporous silica and N-halamine precursor; N-H bonds were successfully transformed to N-Cl bonds after chlorination. Morphology and structure of mesoporous silica were affected to some extent after modification. The surface area of the polymerized sample decreased, but was sufficient for further applications. Compare to the original sample, antimicrobial properties of the polymerized samples with quaternary ammonium groups (QAS) increased slightly. After exposure to dilute household bleach, the chlorinated samples showed excellent antimicrobial properties against 100% of S. aureus (ATCC 6538) (7.63 log) and E. coli O157:H7 (ATCC 43895) (7.52 log) within 10 min. The prepared mesoporous silicas with effective antimicrobial properties could be very useful for potential application in water filtration.

Cytocompatible quaternized carboxymethyl chitosan/poly(vinyl alcohol) blend film loaded copper for antibacterial application.

Antibacterial quaternized carboxymethyl chitosan/poly(vinyl alcohol)/Cu blend film (QCMCS/PVA/Cu blend film) was prepared by quaternary ammonium salt modified carboxymethyl chitosan (QCMCS), PVA and copper sulfate pentahydrate via the process of solution casting and ion adsorption. The successful preparation of QCMCS was proved by EA, NMR and FTIR, and the degree of quaternization is 71.86%. The QCMCS/PVA/Cu blend film was characterized by SEM, AFM and EDX, and the content of the copper is about 1 wt%. Tensile tests and TGA showed that the mechanical and thermal properties were improved after being loaded with copper ions. By loading with Cu2+, the blend film showed good antibacterial activities. About 98.3% of S. aureus and 99.9% of E. coli could be inactivated within 60 min. The cell cytotoxicity was also studied and the results showed that all the prepared films had acceptable cell viability and biocompatible, which indicates that this blend film has potential applications in packaging and biomedical materials.

Preparation of antimicrobial and hemostatic cotton with modified mesoporous particles for biomedical applications.

N-halamine polymers have been successfully attached surfaces of mesoporous materials. The modified mesoporous materials have been applied on the modification of cotton. Soaking in household bleach, the coated cotton shows good antimicrobial efficacy against S. aureus and E. coli O157:H7. The chlorinated samples could completely inactivate 100% S. aureus within 10 min, and 99.99% E. coli O157:H7 within 30 min. The chlorinated sample had better platelet adhesion and red blood cell cohesion than the control sample. The blood clotting index and fluid absorptive property of the samples enhanced after coating with modified mesoporous materials, indicating that the coated sample can prevent wound infection from bacteria and control hemorrhaging simultaneously. The coating of the modified mesoporous materials and N-halamines on cotton has not affect the bioactivity of cotton in the simulated body fluid. The active chlorine of the coated sample decreased 30% after soaking in the whole blood for 1 h. Considering the good antimicrobial efficacy against microorganisms and hemostasis property in blood control of the prepared materials, they have potentials for biomedical applications in wound dressing.