查找使用阿拉丁产品的科研文献

Titanium dioxide nanoparticles functionalized chitosan toward bio-based antibacterial adsorbent for enhanced phosphate capture

Enmin Zong,Chengyi Zhang,Shaoning Wu,Yijun Gao,Jiayao Yang,Xiaohuan Liu,Pingan Song

Developing an eco-friendly, sustainable and antibacterial adsorbent is significant for actual water treatment. Herein, a bio-based antibacterial adsorbent based on titanium dioxide (TiO 2 ) nanoparticles functionalized chitosan (CS) was prepared through an in-situ hydrolysis strategy using titanium oxysulfate as the source of TiO 2 . The as-obtained CS/TiO 2 nanocomposite was characterized by a variety of analytical techniques. According to the Langmuir mode, the adsorption capacity of CS/TiO 2 reached 23.64 mg P g −1 , almost 8 times higher than that of CS. In addition, the normalized adsorption capacity (adsorption value per Ti) of CS/TiO 2 was calculated to be 102.68 mg P g −1 Ti −1 , much higher than pure TiO 2 (60.11 mg P g −1 Ti −1 ). Moreover, CS/TiO 2 exhibited a highly selective capacity for phosphate removal in the presence of competing anions, and showed high stability in a wide pH range of 3.0–8.0. When the phosphate concentration was 2.0 mg P L −1 , the removal efficiency of phosphate reached 99.5 % and the residual concentration was only 10 μg P L −1 , which meets the USEPA standards for eutrophication prevention and control. In addition, after treatment by CS/TiO 2 , the phosphate concentration of two sewage water samples decreased from 1.50 and 1.0 mg P L −1 to <0.10 mg P L −1 , meeting the standard of level II water based on the Environmental Quality Standard of China (GB3838–2002). Ligand exchange and electrostatic interactions are mainly responsible for phosphate adsorption by CS/TiO 2 . Furthermore, the CS/TiO 2 nanocomposites exhibited excellent antibacterial activity , which could avoid biofouling contamination caused by microorganisms. Benefiting from the above advantages, the as-designed CS/TiO 2 nanocomposite has great potential as a bio-based antibacterial adsorbent for phosphate capture or removal from wastewater.

Long-term quality retention and decay inhibition of chestnut using thymol loaded chitosan nanoparticle

Xiaohong Guo,Lijun Chu,Tingting Gu,Sonia Purohit,Liping Kou,Boce Zhang

Thymol (TMO) was loaded into chitosan nanoparticles (CSNPs) to inhibit chestnuts decay during storage. Three chestnut treatments were evaluated, including the CK (uncoated control), CSNPs (coated with chitosan nanoparticles), and TMO-CSNPs (coated with thymol-loaded chitosan nanoparticles). Quality assessments of chestnuts were conducted periodically for up to 180 days, which included starch content, amylase activity, water content, respiration rate, weight loss rate, microbiological indicators, decay rate, and quality evaluation. Results indicated that TMO-CSNPs had significantly less nutrient loss in soluble sugar (10.61%) and starch content (27.72%) compared with CK, which was attributed to low metabolic activities as evident in low amylase activity and respiration rate. Moreover, TMO-CSNPs significantly inhibited the growth of mold and yeast (4.17 log CFU g −1 on day 180) and kept the lowest decay rate (5.33%). This study demonstrates the potential of food nanomaterial as an alternative strategy to promote food security and supply chain resilience.

Development of alginate-chitosan composite scaffold incorporation of bacterial cellulose for bone tissue engineering

Qingmei Zhu,Xiuqiong Chen,Zhaowen Liu,Zhengyue Li,Dongze Li,Huiqiong Yan,Qiang Lin

One-Step Synthesis of Multifunctional Chitosan Hydrogel for Full-Thickness Wound Closure and Healing

Shen Guo,Minghao Yao,Dan Zhang,Yuanmeng He,Rong Chang,Yikun Ren,Fangxia Guan

Multifunctional hydrogel as a sealant or wound dressing with high adhesiveness and excellent antibacterial activity is highly desirable in clinical applications. In this contribution, one-step synthetic hydrogel based on quaternized chitosan (QCS), tannic acid (TA), and ferric iron (Fe(III)) is developed for skin incision closure and Staphylococcus aureus ( S. aureus )-infected wound healing. In this hydrogel system, the ionic bonds and hydrogen bonds between QCS and TA form the main backbone of hydrogel, the metal coordination bonds between TA and Fe(III) (catechol-Fe) endow hydrogel with excellent adhesiveness and (near-infrared light) NIR-responsive photothermal property, and these multiple dynamic physical crosslinks enable QCS/TA/Fe hydrogel with flexible self-healing ability and injectability. Moreover, QCS/TA/Fe hydrogel possesses superior antioxidant, anti-inflammatory, hemostasis, and biocompatibility. Also, it is safe for vital organs. The data from the mouse skin incision model and infected full-thickness skin wound model presented the high wound closure effectiveness and acceleration of the wound healing process by this multifunctional hydrogel, highlighting its great potential in wound management.

Preparation and Characterization of Chitosan–Nano-ZnO Composite Films for Preservation of Cherry Tomatoes

Yu Li,Yu Zhou,Zhouli Wang,Rui Cai,Tianli Yue,Lu Cui

Chitosan is widely used as a natural preservative of fruits and vegetables, but its poor mechanical and water resistances have limited its application. Therefore, in this study, we prepared chitosan composite films by incorporating different amounts of nano-zinc oxide (nano-ZnO) to improve the mechanical properties of chitosan. We also assessed the antibacterial activity of these films against selected microorganisms. The addition of nano-ZnO improved the tensile strength (TS) and elongation at break (EAB) of the chitosan films and reduced their light transmittance. TS and EAB increased from 44.64 ± 1.49 MPa and 5.09 ± 0.38% for pure chitosan film to 46.79 ± 1.65 MPa and 12.26 ± 0.41% for a 0.6% nano-ZnO composite film, respectively. The ultraviolet light transmittance of composite films containing 0.2%, 0.4%, and 0.6% nano-ZnO at 600 nm decreased from 88.2% to 86.0%, 82.7%, and 81.8%, respectively. A disc diffusion test showed that the composite film containing 0.6% nano-ZnO had the strongest antibacterial activity againstAlicyclobacillus acidoterrestris,Staphylococcus aureus,Escherichia coli, andSalmonella. In a 15-day preservation study, chitosan composite films containing 0.6% nano-ZnO maintained the soluble solid content of cherry tomatoes, effectively inhibited their respiration, and exhibited good antibacterial properties against the selected microorganisms. Overall, the prepared chitosan nano-ZnO composite film showed a good preservation effect on cherry tomatoes.Keywords:chitosan;nano-ZnO composite films;preservation;cherry tomatoes;antibacterial activity

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

Xiang He,Ruyue Liu,Huiqing Liu,Ruixiao Wang,Zhenhao Xi,Yixiang Lin,Jie Wang

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-FeCl3and 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 againstE. coli. The overall results show that the CS-TBA-Fe hydrogel with enhanced wet adhesiveness will be a promising tissue adhesive material.Keywords:facile preparation;tunicate-inspired;chitosan;hydrogel;tissue adhesive

Efficient removal of Cd (II) from aqueous solution by chitosan modified kiwi branch biochar

Yuehui Tan,Xirui Wan,Xue Ni,Le Wang,Ting Zhou,Huimin Sun,Nong Wang,Xianqiang Yin

Production of cost-efficient composite materials from low-cost modified biochar for the removal of Cd (II) from wastewater is much needed to meet the growing needs of industrial wastewater treatments . A novel chitosan-modified kiwi branch biochar (CHKB) was fabricated as low-cost modified biochar for the removal of Cd (II) from aqueous solution. Batch adsorption and characterization experiments indicated that the modification of kiwi biochar (KB) by chitosan remarkably improved its adsorption performance. The results revealed that the adsorption isotherms can be best described by a Langmuir model and that a pseudo-second-order model fits the Cd (II) adsorption kinetics well, which indicates that it is a monolayer process controlled by chemisorption . CHKB exhibited a Langmuir maximum adsorption capacity of Cd (II) (126.58 mg g −1 ), whereas that of KB was only 4.26 mg g −1 . The adsorption ability of CHKB was improved by increasing the surface area and an abundance of surface functional groups (-OH, –NH, C O, etc.). The cation exchange, electrostatic interaction, surface complexation, and precipitation were the main mechanisms in the sorption of Cd (II) on CHKB. Excellent adsorption performance, low cost, and environmental-friendliness made CHKB a fantastic adsorbent for the removal of Cd (II) in wastewater.

Underwater superelastic MOF/polyacrylamide/chitosan composite aerogel for efficient 2, 4-dichlorophenoxyacetic acid adsorption

Qun Liu,Kun Xu,Guangxu Hu,Fanming Zeng,Xiao Li,Chun Li,Yu Zhang

MIL-101(Cr)/polyacrylamide/chitosan (named as MIL-101(Cr)/PAM/CSA) composite aerogel with large surface area is synthesized by incorporating MIL-101(Cr) into polyacrylamide/chitosan composite aerogel and used for efficient 2, 4-Dichlorophenoxyacetic acid adsorption. MIL-101(Cr)/PAM/CSA and polyacrylamide/chitosan composite aerogels exhibit good underwater superelastic properties with multi-level network synergistic cross-linking. After introducing MIL-101(Cr) with the mass loading of 30%, the specific surface area of the composite aerogels enlarge from 58.15 m 2 g −1 to 310.94 m 2 g −1 . MIL-101(Cr)/PAM/CSA exhibits high adsorption capacity of 302.45 mg g −1 for 2, 4-Dichlorophenoxyacetic acid (2, 4-D) and stable recycling capability. This work provides a general and effective method to synthesize composite aerogel with underwater superelastic properties, hierarchical pores and large surface area, promising to realize regeneration after compression with reduced solvent usage and costs.

Mussel-Inspired Carboxymethyl Chitosan Hydrogel Coating of Titanium Alloy with Antibacterial and Bioactive Properties

Yanru Ren,Xiaoyan Qin,Mike Barbeck,Yi Hou,Haijun Xu,Luo Liu,Chaoyong Liu

Infection-related titanium implant failure rates remain exceedingly high in the clinic. Functional surface coating represents a very promising strategy to improve the antibacterial and bioactive properties of titanium alloy implants. Here, we describe a novel bioactive surface coating that consists of a mussel-inspired carboxymethyl chitosan hydrogel loaded with silver nanoparticles (AgNPs) to enhance the bioactive properties of the titanium alloy. The preparation of hydrogel is based on gallic acid grafted carboxymethyl chitosan (CMCS-GA) catalyzed by DMTMM (4-(4,6-dimethoxy-1,3,5-triazin-2-yl)-4-methylmorpholinium chloride). To build a firm bonding between the hydrogel and titanium alloy plate, a polydopamine layer was introduced onto the surface of the titanium alloy. With HRP/H2O2catalysis, CMCS-GA can simply form a firm gel layer on the titanium alloy plate through the catechol groups. The surface properties of titanium alloy were characterized by scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS), and water contact angle. Silver nanoparticles were loaded into the gel layer by in situ reduction to enhance the antibacterial properties. In vitro antibacterial and cell viability experiments showed that the AgNPs-loaded Ti-gel possesses excellent antibacterial properties and did not affect the proliferation of rabbit mesenchymal stem cells (MSCs).Keywords:carboxymethyl chitosan;gallic acid;titanium alloy;DMTMM;HRP/H2O2;catechol group;hydrogel coating;antibacterial

Cerium ions crosslinked sodium alginate-carboxymethyl chitosan spheres with antibacterial activity for wound healing

Tengfei Ma,Xinyun Zhai,Yongkang Huang,Mengzhen Zhang,Pengfei Li,Yaping Du

For wound healing, wound infection caused by bacteria is one of the important reasons that delay wound healing process. Therefore, it is very meaningful to develop a multifunctional wound dressing with antibacterial capability to accelerate wound healing. Sodium alginate (SA) and carboxymethyl chitosan (CMCS) are the most commonly used compositions in wound dressing, but their poor stability inhibits the further applications. Introducing CMCS and using cerium ions (Ce 3+ ) to crosslink CMCS and SA to form SA-CMCS hybrid spheres by electrostatic spray method, can not only improve the stability of SA hydrogels, but also endow the spheres with excellent antibacterial properties due to the characteristics of Ce 3+ . The gradual release of Ce 3+ from the SA-CMCS spheres can effectively inhibit the growth of Staphylococcus aureus ( S. aureus ) and Escherichia coli ( E. coli ). Combining the wound healing promotion ability of SA and CMCS, this kind of wound dressing can not only avoid wound infection caused by bacteria effectively, but also accelerate wound healing, thus it is an easily prepared material with potential applications in skin defect repair.

Biobased Tannic Acid-Chitosan Composite Membranes as Reusable Adsorbents for Effective Enrichment of Phosphopeptides

Ruizhi Tang,Lei Pan,Quan Bai,Cong Li,Shujuan Ma,Junjie Ou,Yehua Shen

High-performance reusable materials from renewable resources are rare and urgently required in bioseparation. Herein, a series of tannic acid-chitosan composite membranes for the enrichment of phosphopeptides were fabricated by the freeze casting method. First, a tannic acid-chitosan composite membrane was acquired via the multiple hydrogen bonds between tannic acid and chitosan, which had a long-range aligned three-dimensional microstructure. Second, a covalent–hydrogen bond hybrid composite was also fabricated, with stable and aligned honeycomb-like microstructures that formed by the synergy of covalence and hydrogen bonding. Besides, a ternary composite membrane was “one-pot” synthesized by the copolymerization of tannic acid, chitosan, and Ti4+ ions, indicating the feasibility of involving metal ions in the composition of the polymer skeleton in place of additional modification steps. The as-prepared chitosan composite membranes exhibited excellent performance in the enrichment of phosphopeptides from β-casein tryptic digest and human serum. Benefitting from the long-range aligned honeycomb-like structure coordinated by hydrogen bonds and covalent bonds, and a large number of pyrogallol functional groups provided by tannic acid, the covalent–hydrogen bond hybrid membrane showed excellent reusability and could be reused up to 16 times in phosphopeptide enrichment, as far as we know, which is the best reported result to date.

In situ formed tissue-adhesive carboxymethyl chitosan hydrogels through photoclick chemistry for wound healing

Jun Wang,Fei Qi,Huiying Feng,Anqi Xu,Dao-Qiang Lu,Junru Liang,Ziwen Zhang,Jie Li,Dahai Liu,Bin Zhang,Yanling Hu

Chitosan-based hydrogels crosslinked through covalent bonds have been extensively researched for their remarkable wound healing properties. However, their practical application has been limited due to the complexity of the preparation process and weak tissue-adhesive strength. In this study, we present a straightforward method for producing tissue-adhesive carboxymethyl chitosan hydrogels consisting of a single component, without the need for an initiator, catalyst, or external crosslinking agent. We synthesized o -nitrobenzyl alcohol-conjugated carboxymethyl chitosan and utilized 365 nm LED light irradiation to self-crosslink the hydrogels through photo-triggered o -nitrobenzyl alcohol and primary amine cyclization. The resulting o -nitrosobenzaldehyde groups not only covalently crosslinked carboxymethyl chitosan chains but also formed robust covalent bonds with the amino groups from the tissue surface, resulting in enhanced adhesion. Furthermore, the hydrogels demonstrated favorable biocompatibility. In vivo studies using a mice full-thickness defect model demonstrated that the hydrogel significantly accelerated wound healing, indicating their potential as a wound repair dressing.