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1.
Langmuir ; 2024 May 14.
Artículo en Inglés | MEDLINE | ID: mdl-38743262

RESUMEN

The synergistic effect between bimetallic catalysts has been confirmed as an effective method for activating persulfate (PMS). Therefore, we immobilized copper-cobalt on chitosan to prepare bimetallic carbon catalysts for PMS activation and degradation of reactive dyes. Experimental results demonstrate that the CuCo-CTs/PMS catalytic degradation system exhibits excellent degradation performance toward various types of reactive dyes (e.g., Ethyl violet, Chlortalidone, and Di chlorotriazine), with degradation rates reaching 90% within 30 min. CuCo-CTs exhibit high catalytic activity over a wide pH range of 3-11 at room temperature and under static conditions, degrading over 92% of RV5 within 60 min. ultraviolet-visible (UV-vis) spectroscopy and color changes in the dye solution confirm the effective degradation of RV5, with a degradation rate of 97.2% within 10 min. Additionally, CuCo-CTs demonstrate good stability and reusability, maintaining a degradation rate of 92.8% after eight cycles. Kinetic studies indicate that the degradation follows pseudo-first-order kinetics. Furthermore, based on the results of radical scavenging experiments, the catalytic degradation mechanism of the dye involves both radical and nonradical pathways, with 1O2 identified as the primary active species. This study provides insights and experimental evidence for the application of persulfate oxidation in the treatment of dyeing wastewater.

2.
Int J Biol Macromol ; 263(Pt 2): 130512, 2024 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-38423418

RESUMEN

Dressings seamlessly attached to the open wound bed are necessary for fully unleashing the dressing healing ability, as leaving the voids beneath the dressing poses infection hazards. The present study prepared an instant mucus dressing (IMD) of polyethylene oxide (PEO) reinforced by chitosan (CS) nanofiber scaffold, which formed by immersing PEO/CS nanofiber mat in water. The PEO/CS nanofiber mat were fabricated by the solution blow spinning (SBS) method using PEO and CS mixed solutions. Attenuated total reflection Fourier transform infrared spectroscopy (FTIR-ATR), transmission electron microscope (TEM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) and differential scan calorimetry (DSC) analyses indicate that PEO macromolecules formed the most of nanofiber shell due to their lower surface tension while CS macromolecules stayed mainly inside the fiber as the core. When such a PEO/CS nanofiber mat was immersed in water, PEO swelled to form mucus dressing reinforced by CS inside the nanofiber, which was fluidic and able to fully fill the voids on the wound. In vivo rat experiment verified that the dressing significantly accelerated the open wound healing through seamlessly attaching of mucus to the open wound and providing moist environment. The dressings exhibit good platelets and whole blood cells adhesion properties, excellent hemostasis function and no cytotoxicity. This instant mucus dressing provided a new perspective for manufacturing high performance open wound dressings.


Asunto(s)
Quitosano , Nanofibras , Ratas , Animales , Quitosano/química , Polietilenglicoles/química , Nanofibras/química , Cicatrización de Heridas , Vendajes , Agua , Antibacterianos/química
3.
Int J Biol Macromol ; 261(Pt 2): 129929, 2024 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-38311139

RESUMEN

Recently, metal-organic frameworks (MOFs) have been widely developed due to the rich porosity, excellent framework structure and multifunctional nature. Meanwhile, a series of MOFs crystals and MOF-based composites have been emerged. However, the widespread applications of MOFs are hindered by challenges such as rigidity, fragility, solution instability, and processing difficulties. In this study, we addressed these limitations by employing an in-situ green growth approach to prepare a zeolitic imidazolate frameworks-8@poly (γ-glutamic acid) hydrogel (ZIF-8@γ-PGA) with hierarchical structures. This innovative method effectively resolves the inherent issues associated with MOFs. Furthermore, the ZIF-8@γ-PGA hydrogel is utilized for dye adsorption, demonstrating an impressive maximum adsorption capacity of 1130 ± 1 mg/g for methylene blue (MB). The adsorption behavior exhibits an excellent agreement with both the kinetic model and isotherm. Meanwhile, because the adsorbent raw materials are all green non-toxic materials, multiple applications of materials can also be realized. Significantly, the results of antibacterial experiments showed that the ZIF-8@γ-PGA hydrogel after in-situ growth of ZIF-8 had better antibacterial properties. Thus, the ZIF-8@γ-PGA hydrogel has great potential for development in wound dressings, sustained drug owing to its biocompatibility and antibacterial activity.


Asunto(s)
Estructuras Metalorgánicas , Zeolitas , Hidrogeles/química , Ácido Glutámico , Adsorción , Zeolitas/química , Antibacterianos
4.
Small ; : e2310046, 2024 Jan 06.
Artículo en Inglés | MEDLINE | ID: mdl-38183373

RESUMEN

Hydrogels are widely used in tissue engineering, soft robotics and wearable electronics. However, it is difficult to achieve both the required toughness and stiffness, which severely hampers their application as load-bearing materials. This study presents a strategy to develop a hard and tough composite hydrogel. Herein, flexible SiO2 nanofibers (SNF) are dispersed homogeneously in a polyvinyl alcohol (PVA) matrix using the synergistic effect of freeze-drying and annealing through the phase separation, the modulation of macromolecular chain movement and the promotion of macromolecular crystallization. When the stress is applied, the strong molecular interaction between PVA and SNF effectively disperses the load damage to the substrate. Freeze-dried and annealed-flexible SiO2 nanofibers/polyvinyl alcohol (FDA-SNF/PVA) reaches a preferred balance between enhanced stiffness (13.71 ± 0.28 MPa) and toughness (9.9 ± 0.4 MJ m-3 ). Besides, FDA-SNF/PVA hydrogel has a high tensile strength of 7.84 ± 0.10 MPa, super elasticity (no plastic deformation under 100 cycles of stretching), fast deformation recovery ability and excellent mechanical properties that are superior to the other tough PVA hydrogels, providing an effective way to optimize the mechanical properties of hydrogels for potential applications in artificial tendons and ligaments.

5.
Environ Technol ; 44(20): 3121-3130, 2023 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-35293270

RESUMEN

Polyethylene terephthalate (PET) is an important basic polymer, which was used widely in variety of fields. Due to its high crystallinity, compact structure and strong surface hydrophobicity, PET has prominent resistance to biodegradation. In recent years, microplastics, especially polyethylene terephthalate (PET) microplastics, was considered as serious threaten to ecosystems. In this study, alkali-resistant bacteria were used as whole-cell catalysts to try to improve the biodegradation of PET microplastics by increasing the bio-interfacial activity of the polymer substrate. Surfactants were applicated to enhance interfacial activation of enzyme and PET interactions. And an integrated strategy was constructed based on alkali resistant bacteria to catalysis the hydrolysis of PET. The results showed that Tween 20 had the most obvious promoting effect among the four interfacial biocatalysts on biological-chemical combined hydrolysis of PET microplastics with whole-cell biocatalysts in alkaline environment. Obvious etching and fracture were observed on the PET fibre surface after biodegradation in presence of surfactant. The weight loss rate of PET substrate can reach 11.04% after 5 days of biodegradation. Thus, this research provides a promising method for efficient degradation of PET microplastics.


Asunto(s)
Biodegradación Ambiental , Microplásticos , Tereftalatos Polietilenos , Bacterias/metabolismo , Ecosistema , Plásticos , Tereftalatos Polietilenos/química , Tereftalatos Polietilenos/metabolismo , Polímeros
6.
Langmuir ; 38(39): 12095-12102, 2022 Oct 04.
Artículo en Inglés | MEDLINE | ID: mdl-36150189

RESUMEN

In view of the environmental pollution caused by the widespread use of reactive dyes in the printing and dyeing industry, the modified cotton fabric was loaded with the extremely stable metal-organic frame (MOF) material UiO-66 for removing reactive dyes from colored wastewater. UiO-66/cotton fabric was prepared by in situ synthesis, and its surface morphology and structure were analyzed by XRD, SEM, BET, and XPS. The adsorption performance of UiO-66/cotton fabric on reactive dyes was investigated by adsorbent dosage, adsorption time and temperature, dye concentration, pH, and so on. The results indicated that the adsorption equilibrium time of UiO-66/cotton fabric on reactive orange 16 was 120 min, and the removal rate was about 98%. The adsorption process belongs to simple molecular layer chemisorption and can be regarded as a spontaneous heat absorption reaction, which was consistent with the proposed secondary kinetic model and Langmuir isothermal adsorption model. In addition, the reactive dyes with a higher molecular weight of each sulfonic acid group are more hydrophobic, and the dyes are more likely to aggregate and deposit on the adsorbent surface by electrostatic attraction, hydrogen bonding, and π-π accumulation. Therefore, this work provides a potential UiO-66/cotton fabric application for the effective adsorption of reactive dyes in textile wastewater.

7.
ACS Appl Mater Interfaces ; 14(16): 18884-18900, 2022 Apr 27.
Artículo en Inglés | MEDLINE | ID: mdl-35427121

RESUMEN

Textile-based flexible electronic devices have attracted tremendous attention in wearable sensors due to their excellent skin affinity and conformability. However, the washing process of such devices may damage the electronic components. Here, a textile-based piezoresistive sensor with ultrahigh sensitivity was fabricated through the layered integration of gold nanowire (AuNW)-impregnated cotton fabric and silver ink screen-printed nylon fabric electrodes, sealing with Parafilm. The prepared piezoresistive sensing patch exhibits outstanding performance, including high sensitivity (914.970 kPa-1, <100 Pa), a fast response time (load: 38 ms, recovery: 34 ms), and a low detection limit (0.49 Pa). More importantly, it can maintain a stable signal output even after 30 000 s of loading-unloading cycles. Furthermore, this sensing patch can efficiently detect breathing, pulse, heart rate, and joint movements during the activities. After five cycles of mechanical washing, the piezoresistive performance keeps 90.3%, demonstrating the high feasibility of this sensor in practical applications. This sensor has a simple fabrication, with good fatigue resistance and durability due to its all-fabric core element. It provides a strategy to address the machine-washing issues in textile electronics. This washable textile sensor is expected to show significant potential in future applications of health monitoring, human-machine interfaces, and artificial skin.


Asunto(s)
Nanocables , Dispositivos Electrónicos Vestibles , Electrodos , Oro , Humanos , Textiles
8.
Int J Biol Macromol ; 202: 438-452, 2022 Mar 31.
Artículo en Inglés | MEDLINE | ID: mdl-35063481

RESUMEN

Building bio-based hydrogels with high strength and biocompatibility is still a challenge. Herein, we successfully constructed a hybrid double-network (DN) full biological hydrogel with excellent mechanical properties and biocompatibility by introducing a physically cross-linked gelatin (GEL) network in a covalently cross-linked poly (γ-glutamic acid) (γ-PGA) network. The γ-PGA-GEL DN hydrogel demonstrated ultra-high compression performance (38 MPa), which was better than all currently reported γ-PGA-based hydrogels, and its tensile performance (0.27 MPa) was also satisfactory. Due to the unique multi-crosslinked DN structure, the γ-PGA-GEL DN hydrogel had better recovery and healing properties than those of the γ-PGA single-network (SN) hydrogel. In addition, the γ-PGA-GEL DN hydrogel exhibited good transparency, swelling and degradability. In vitro cell experiments demonstrated that the γ-PGA-GEL DN hydrogel was beneficial to cell adhesion and proliferation. The evaluation of the full-thickness skin defects model in rats exhibited that the γ-PGA-GEL DN hydrogel could significantly accelerate wound healing. These results indicated that the γ-PGA-GEL DN hydrogel was an ideal candidate material for wound dressing.


Asunto(s)
Gelatina , Hidrogeles , Animales , Vendajes , Ácido Glutámico , Hidrogeles/química , Hidrogeles/farmacología , Ratas , Cicatrización de Heridas
9.
Lab Chip ; 21(5): 916-932, 2021 03 09.
Artículo en Inglés | MEDLINE | ID: mdl-33438703

RESUMEN

Flexible biosensors for monitoring systems have emerged as a promising portable diagnostics platform due to their potential for in situ point-of-care (POC) analytic devices. Assessment of biological analytes in sweat can provide essential information for human physiology. Conventional measurements rely on laboratory equipment. This work exploits an alternative approach for epidermal sweat sensing and detection through a wearable microfluidic thread/fabric-based analytical device (µTFAD). This µTFAD is a flexible and skin-mounted band that integrates hydrophilic dot-patterns with a hydrophobic surface via embroidering thread into fabric. After chromogenic reaction treatment, the thread-embroidered patterns serve as the detection zones for sweat transferred by the hydrophilic threads, enabling precise analysis of local sweat loss, pH and concentrations of chloride and glucose in sweat. Colorimetric reference markers embroidered surrounding the working dots provide accurate data readout either by apparent color comparison or by digital acquirement through smartphone-assisted calibration plots. On-body tests were conducted on five healthy volunteers. Detection results of pH, chloride and glucose in sweat from the volunteers were 5.0-6.0, 25-80 mM and 50-200 µM by apparent color comparison with reference markers through direct visual observation. Similar results of 5.47-6.30, 50-77 mM and 47-66 µM for pH, chloride and glucose were obtained through calibration plots based on the RGB values from the smartphone app Lanse®. The limit of detection (LOD) is 10 mM for chloride concentration, 4.0-9.0 for pH and 10 µM for glucose concentration, respectively. For local sweat loss, it is found that the forehead is the region of heavy sweat loss. Sweat secretion is a cumulating process with a lower sweat rate at the beginning which increases as body movement continues along with increased heat production. These results demonstrate the capability and availability of our sensing device for quantitative detection of multiple biomarkers in sweat, suggesting the great potential for development of feasible non-invasive biosensors, with a similar performance to conventional measurements.


Asunto(s)
Técnicas Biosensibles , Dispositivos Electrónicos Vestibles , Humanos , Dispositivos Laboratorio en un Chip , Microfluídica , Sudor
10.
Int J Biol Macromol ; 170: 354-365, 2021 Feb 15.
Artículo en Inglés | MEDLINE | ID: mdl-33359810

RESUMEN

Natural polymer hydrogels are expected to be promising biomaterial because of its excellent biocompatibility and biodegradability, but they are soft and easily broken. Herein, the poly (γ-glutamic acid) (γ-PGA)/bacterial cellulose (BC) composite hydrogels with excellent mechanical properties were constructed by introducing bacterial cellulose. The γ-PGA/BC composite hydrogels were obtained by the covalent cross-linking of γ-PGA in the BC nanofibers suspensions. The γ-PGA/BC composite hydrogels exhibited excellent strength and toughness due to the more effective energy dissipation of hydrogen bonds network among BC nanofibers and γ-PGA hydrogel matrix and BC also acts as an enhancer. The compressive fracture strength and toughness of the γ-PGA/BC composite hydrogels could reach up to 5.72 MPa and 0.42 MJ/m3 respectively. Additionally, the tensile strength of γ-PGA/BC composite hydrogels were improved 8.16 times compared with γ-PGA single network hydrogels. More significantly, BC could disperse evenly in the γ-PGA hydrogels because of the hydrophilic nature of γ-PGA and BC nanofillers, which led to good interface compatibility. The result of cytotoxicity tests indicated that γ-PGA/BC composite hydrogels present excellent cytocompatibility, which suggested that the γ-PGA/BC composite hydrogels could serve as promising materials for many biomaterial related applications.


Asunto(s)
Celulosa/química , Hidrogeles/química , Ácido Poliglutámico/análogos & derivados , Bacterias , Materiales Biocompatibles/química , Supervivencia Celular , Fuerza Compresiva , Ácido Glutámico/química , Nanofibras/química , Ácido Poliglutámico/química , Polímeros , Resistencia a la Tracción
11.
Nanomaterials (Basel) ; 10(10)2020 Sep 25.
Artículo en Inglés | MEDLINE | ID: mdl-32992743

RESUMEN

Heteroatom doping is an effective way to raise the electrochemical properties of carbon materials. In this paper, a novel electrode material including nitrogen, phosphorus, and sulfur co-doped pyrolyzed bacterial cellulose (N/P/S-PBC) nanofibers was produced. The morphologies, structure characteristics and electrochemical performances of the materials were investigated by Scanning electron microscopy, Fourier transform infrared spectra, X-ray diffraction patterns, X-ray photoelectronic spectroscopy, N2 sorption analysis and electrochemical measurements. When 3.9 atom% of nitrogen, 1.22 atom% of phosphorus and 0.6 atom% of sulfur co-doped into PBC, the specific capacitance of N/P/S-PBC at 1.0 A/g was 255 F/g and the N/P/S-PBC supercapacitors' energy density at 1 A/g was 8.48 Wh/kg with a power density of 489.45 W/kg, which were better than those of the N/P-PBC and N/S-PBC supercapacitors. This material may be a very good candidate as the promising electrode materials for high-performance supercapacitors.

12.
RSC Adv ; 10(30): 17731-17738, 2020 May 05.
Artículo en Inglés | MEDLINE | ID: mdl-35515608

RESUMEN

This study reports the design of a stimulus-responsive fabric incorporating a combination of microcapsules, containing polyelectrolytes poly(allylamine hydrochloride) (PAH) and poly(styrene sulfonate) sodium salt (PSS), formed via a layer-by-layer (LBL) approach. The use of PAH and PSS ensured that the microcapsule structure was robust and pH-sensitive. SEM and TEM studies showed that the composite microcapsule (PAH/PSS) n PAH had a spherical morphology with a hollow structure. FTIR demonstrated the presence of PAH and PSS, confirming the composition of the microcapsule shell. DSC showed that the microcapsules were thermally stable. The size of the microcapsules ranged from 4 µm to 6 µm. The hollow microcapsules can be used as a carrier for loading and releasing chemicals under different pH conditions. The release rate of Rhodamine-B from (PAH/PSS) n PAH microcapsules was higher at pH 5.8 than that at 7.4, confirming the pH sensitivity. The hollow structure of (PAH/PSS) n PAH microcapsules is expected to act as a carrier and medium to introduce functional chemicals into the fabric with long-lasting property and pH stimulus responsivity. Furthermore, a positively charged compound with ethylene oxide groups was added during the coating process as a crosslinker binding (PAH/PSS)2PAH for the microcapsules with the cotton fabric more efficiently. Using this method, numerous substances, e.g., drugs, dyes, natural herbs, or perfumes, could be stored into the LBL microcapsules for a relatively long time, constantly releasing them from the coated textiles. Since LBL microcapsules were easy to combine with fabrics, this study provided a feasible approach for the preparation of functional stimulus-responsive textiles.

13.
Polymers (Basel) ; 11(6)2019 Jun 02.
Artículo en Inglés | MEDLINE | ID: mdl-31159509

RESUMEN

Flexible conductive materials have greatly promoted the rapid development of intelligent and wearable textiles. This article reports the design of flexible polypyrrole/bacterial cellulose (PPy/BC) conductive nanocomposites by in situ chemical polymerization. Box-Behnken response surface methodology has been applied to optimize the process. The effects of the pyrrole amount, the molar ratio of HCl to pyrrole and polymerization time on conductivity were investigated. A flexible PPy/BC nanocomposite was obtained with an outstanding electrical conductivity as high as 7.34 S cm-1. Morphological, thermal stability and electrochemical properties of the nanocomposite were also studied. The flexible PPy/BC composite with a core-sheath structure exhibited higher thermal stability than pure cellulose, possessed a high areal capacitance of 1001.26 mF cm-2 at the discharge current density of 1 mA cm-2, but its cycling stability could be further improved. The findings of this research demonstrate that the response surface methodology is one of the most effective approaches for optimizing the conditions of synthesis. It also indicates that the PPy/BC composite is a promising material for applications in intelligent and wearable textiles.

14.
Nanomaterials (Basel) ; 9(1)2019 Jan 18.
Artículo en Inglés | MEDLINE | ID: mdl-30669357

RESUMEN

Microbial pigments, regarded as the most potential biomass pigments, have lately attracted increasing attention in textile dyeing due to their sustainability and cleaner production. The pyrrole structure microbial pigment, called prodigiosin, recently have become a research hotspot for its bright colors and antibacterial function. However, in most case the extraction and preparation are time-consuming and expensive processes since these kinds of microbial pigments are intracellular metabolites. In order to promote the application of microbial pigments in textile dyeing, a novel idea of preparing dye liquid of pyrrole structure pigments based on fermentation broth was put forward via increasing the proportion of extracellular pigments. A model membrane platform was established with a planar lipid bilayer to investigate transmembrane transport of microbial pigments and permeability barrier of cell membrane. The nano-dispersion of pigments was produced as the dye liquor owing to high-throughput transmembrane transfer of intracellular pigments and the increase of extracellular pigments proportion. The results indicated that the size and surface electrical properties of the pigments had contributed much to the mass transfer. It is also showed that transmembrane transmission of the intracellular pigments could be regulated by physical and chemical methods. With the improvement of transmembrane transfer efficiency of microbial pigments and the proportion of extracellular pigments, the complicated biological separation process could be avoided and the application of microbial pigments in textile dyeing can be promoted.

15.
Nanomaterials (Basel) ; 8(5)2018 May 14.
Artículo en Inglés | MEDLINE | ID: mdl-29757942

RESUMEN

In wound care management, the prevention of wound infection and the retention of an appropriate level of moisture are two major challenges. Therefore, designing an excellent antibacterial hydrogel with a suitable water-adsorbing capacity is very important to improve the development of wound dressings. In this paper, a novel silver nanoparticles/poly (gamma-glutamic acid) (γ-PGA) composite dressing was prepared for biomedical applications. The promoted wound-healing ability of the hydrogels were systematically evaluated with the aim of attaining a novel and effective wound dressing. A diffusion study showed that hydrogels can continuously release antibacterial factors (Ag). Hydrogels contain a high percentage of water, providing an ideal moist environment for tissue regeneration, while also preventing contraction of the wound. Moreover, an in vivo, wound-healing model evaluation of artificial wounds in mice indicated that silver/γ-PGA hydrogels could significantly promote wound healing. Histological examination revealed that hydrogels can successfully help to reconstruct intact epidermis and collagen deposition during 14 days of impaired wound healing. Overall, this research could shed new light on the design of antibacterial silver/γ-PGA hydrogels with potential applications in wound dressing.

16.
R Soc Open Sci ; 5(1): 171134, 2018 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-29410827

RESUMEN

Biomass pigments have been regarded as promising alternatives to conventional synthetic dyestuffs for the development of sustainable and clean dyeing. This investigation focused on in situ dyeing of fabrics with biopigments derived from tea polyphenols via non-enzymatic browning reaction. The average particle size of dyed residual liquor with natural tea polyphenol was 717.0 nm (ranging from 615.5 to 811.2 nm), and the Integ value of dyed wool fabrics was the greatest compared to those of counterparts. In addition, the Integ values of dyed fabrics with residual liquor were much bigger than those with the first reaction solutions when dyed by identical dyeing liquor. As a result, the dyeing process could be carried out many times because the concentration of the residual liquor was relatively superior. All dyed fabrics acquired admirable rubbing as well as washing fastness, and the relevant dyeing mechanism has been analysed in the paper.

17.
Polymers (Basel) ; 10(12)2018 Nov 30.
Artículo en Inglés | MEDLINE | ID: mdl-30961251

RESUMEN

At present, the pollution of microplastic directly threatens ecology, food safety and even human health. Polyethylene terephthalate (PET) is one of the most common of microplastics. In this study, the micro-size PET particles were employed as analog of microplastic. The engineered strain, which can growth with PET as sole carbon source, was used as biocatalyst for biodegradation of PET particles. A combinatorial processing based on whole-cell biocatalysts was constructed for biodegradation of PET. Compared with enzymes, the products can be used by strain growth and do not accumulated in culture solution. Thus, feedback inhibition of products can be avoided. When PET was treated with the alkaline strain under high pH conditions, the product concentration was higher and the size of PET particles decreased dramatically than that of the biocatalyst under neutral conditions. This shows that the method of combined processing of alkali and organisms is more efficient for biodegradation of PET. The novel approach of combinatorial processing of PET based on whole-cell biocatalysis provides an attractive avenue for the biodegradation of micplastics.

18.
Polymers (Basel) ; 10(2)2018 Jan 24.
Artículo en Inglés | MEDLINE | ID: mdl-30966148

RESUMEN

In this paper, poly γ-glutamic acid/ε-polylysine (γ-PGA/ε-PL) hydrogels were successful prepared. The γ-PGA/ε-PL hydrogels could be used to remove Na⁺, Ca2+, and Cr3+ from aqueous solution and were characterized by scanning electron microscopy. The performance of hydrogels were estimated under different ionic concentration, temperature, and pH. The results showed that the ionic concentration and the pH significantly influenced the swelling capacity of γ-PGA/ε-PL hydrogels. The swelling capacities of γ-PGA/ε-PL hydrogels were decreased with the increase of the ionic concentration. However, the swelling capacity of the γ-PGA/ε-PL hydrogel was increased with the increase of the pH. The swelling kinetics indicated that γ-PGA/ε-PL hydrogels presented a more limited swelling degree in metal ion solutions with higher ionic valence numbers than in ion solutions with lower ionic valence numbers. However, the swelling kinetics of γ-PGA/ε-PL hydrogels showed that they proposed a satisfactory description in NaCl and CaCl2 solutions. The adsorption process was fitted with a pseudo-second-order rate equation model. Moreover, the desorption kinetics of γ-PGA/ε-PL hydrogels showed that they could release most of the adsorption ions. Considering the biocompatibility, biodegradability, and ionic-sensitive properties, we propose that these γ-PGA/ε-PL hydrogels have high potential to be used in environmental protection, medical treatment, and other related fields.

19.
Polymers (Basel) ; 10(2)2018 Feb 15.
Artículo en Inglés | MEDLINE | ID: mdl-30966232

RESUMEN

Natural products have been believed to be a promising source to obtain ecological dyes and pigments. Plant polyphenol is a kind of significant natural compound, and tea provides a rich source of polyphenols. In this study, biocolorant derived from phenolic compounds was generated based on laccase-catalyzed oxidative polymerization, and eco-dyeing of silk and wool fabrics with pigments derived from tea was investigated under the influence of pH variation. This work demonstrated that the dyeing property was better under acidic conditions compared to alkalinity, and fixation rate was the best when pH value was 3. Furthermore, breaking strength of dyed fabrics sharply reduced under the condition of pH 11. Eventually, the dyeing method was an eco-friendly process, which was based on bioconversion, and no mordant was added during the process of dyeing.

20.
Polymers (Basel) ; 9(10)2017 Sep 23.
Artículo en Inglés | MEDLINE | ID: mdl-30965771

RESUMEN

This study developed a novel pH-mediated antimicrobial dyeing process of cotton with prodigiosins nanomicelles produced by microbial fermentation. The average diameter of the pigment nanomicelles was 223.8 nm (range of 92.4⁻510.2 nm), and the pigment concentration was 76.46 mg/L. It was found that the superior dyeing effect of cotton fabric was achieved by adjusting the dye bath pH. When the pH was three, dyed cotton under 90 °C for 60 min exhibited the greatest color strength with good rubbing, washing and perspiration color fastness. By the breaking strength test and XRD analysis, it was concluded that the cotton dyed under the optimum condition almost suffered no damage. In addition, due to the presence of prodigiosins, dyed cotton fabric under the optimal process showed outstanding bacteriostatic rates of 99.2% and 85.5% against Staphylococcus aureus and Escherichia coli, respectively. This research provided an eco-friendly and widely-applicable approach for antimicrobial intracellular pigments with the property of pH-sensitive solubility in water to endow cellulose fabric with color and antibacterial activity.

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