查找使用阿拉丁产品的科研文献

Influence of chitosan-sodium alginate pretreated with ultrasound on the enzyme activity, viscosity and structure of papain

Liping Feng,Yanping Cao,Duoxia Xu,Dandan Zhang,Zhenghua Huang

BACKGROUND Ultrasound treatment has been shown to be an effective technique for improving the activity of immobilized enzymes. However, its mechanism is unclear. RESULTS The effect of ultrasonic pretreated chitosan-sodium alginate (CHI-ALG) on the enzymatic activity of papain was investigated via a single factor (temperature, time, frequency, power) experiment. The maximum relative enzyme activity of papain was observed when it was mixed with ultrasound pretreated CHI-ALG at 135 kHz, 0.25 W cm −2 and 50 °C for 20 min, during which the relative activity increased by 72.14% compared to untreated CHI-ALG. Viscosity analysis of papain mixed with CHI-ALG pretreated and untreated with ultrasound revealed that stronger association interactions between the polymers were formed compared to the untreated sample. Fluorescence and circular dichroism spectra indicated that the ultrasonic pretreatment of CHI-ALG increased the number of tryptophan on the papain surface and also increased the content of α -helix by 6.97% and decreased the content of β -sheet by 3.45% compared to the untreated solution. CONCLUSION The results of the present study indicate that papain combined with CHI-ALG pretreated with the appropriate ultrasound could be effective technique for improving the activity of immobilized enzymes as a result of changes in its structure and intermolecular interactions. It is important to extend the application of CHI-ALG gel in the immobilized enzyme industry. © 2016 Society of Chemical Industry

Flexible and anti-freezing zinc-ion batteries using a guar-gum/sodium-alginate/ethylene-glycol hydrogel electrolyte

Jiawei Wang,Yuan Huang,Binbin Liu,Zixuan Li,Jiyan Zhang,Guoshen Yang,Pritesh Hiralal,Shunyu Jin,Hang Zhou

Natural polymer hydrogels are promising candidates for solid-state electrolytes in zinc-ion batteries. They are safe, biocompatible, and mechanically robust. However, the ionic conductivity of most natural polymer-based hydrogels is unsatisfactory, and they are particularly problematic at sub-zero temperatures because freezing severely limits their functionality. In this study, we fabricate composite hydrogels with high ionic conductivity (25.37 mS cm −1 ). This is done by blending two kinds of natural polymers, guar gum (GG) and sodium alginate (SA). The zinc-ion batteries with GG/SA hydrogel electrolytes show a superior electrochemical performance (354.9 mAh g −1 at 0.15 A g −1 , 137.0 mAh g −1 at 6 A g −1 and capacity retention of 91.52% over 1000 cycles) than the zinc-ion batteries with the pure GG hydrogel electrolyte. In addition, to extend the application range of GG/SA hydrogels into the sub-zero temperature region, we introduce ethylene glycol (EG) into GG/SA to form GG/SA/EG anti-freeze hydrogel. Below -20 °C, the GG/SA/EG hydrogel maintains a high ionic-conductivity (6.19 mS cm −1 ), and the zinc-ion batteries, which were made of GG/SA/EG hydrogel electrolyte, showed an excellent low-temperature discharge performance, for a specific capacity of 181.5 mAh g −1 at 0.1 A g −1 . This study describes a new approach for the development of natural polymer-based hydrogel electrolytes with high ionic-conductivity and good anti-freeze capability.

Fabrication of thermal insulation sodium alginate/SiO2 composite aerogel with superior radiative cooling function for firefighting clothing

Qing Jiang,Yuhang Wan,Xiaoqian Li,Xueru Qu,Shengnan Ouyang,Yi Qin,Zhenyu Zhu,Yushu Wang,Hualing He,Zhicai Yu

PurposeThis study aims to evaluate the thermal performance of sodium alginate (SA) aerogel attached to nano SiO2and its radiative cooling effect on firefighting clothing without environmental pollution.Design/methodology/approachSA/SiO2aerogel with refractory heat insulation and enhanced radiative cooling performance was fabricated by freeze-drying method, which can be used in firefighting clothing. The microstructure, chemical composition, thermal stability, and thermal emissivity were analyzed using Fourier transform infrared spectroscopy, scanning electron microscopy, thermogravimetric analyzer and infrared emissivity measurement instrument. The radiative cooling effect of aerogel was studied using thermal infrared imager and thermocouple.FindingsWhen the addition of SiO2is 25% of SA, the prepared aerogel has excellent heat insulation and a high radiative cooling effect. Under a clear sky, the temperature of SA/SiO2aerogel is 9.4°C lower than that of pure SA aerogel and 22.1°C lower than that of the simulated environment. In addition, aerogel has more exceptional heat insulation effect than other common fabrics in the heat insulation performance test.Research limitations/implicationsSA/SiO2aerogel has passive radiative cooling function, which can efficaciously economize global energy, and it is paramount to environment-friendly cooling.Practical implicationsThis method could pave the way for high-performance cooling materials designed for firefighting clothing to keep maintain the wearing comfort of firefighters.Originality/valueSA/SiO2aerogel used in firefighting clothing can release heat to the low-temperature outer space in the form of thermal radiation to achieve its own cooling purpose, without additional energy supply.Graphical abstract

Enhanced carbon dispersion of polyacrylamide/sodium alginate hydrogels via irregular copolymerization imidazolyl ionic liquid for flexible sensor

Tong Hongping,Li Shuangqing,Dong Xiuling,Xing Zheng,Li Haitao,Liu Xiang

Electrically conductive hydrogel matrices embedded with carbon-based nanomaterials have undergone comprehensive scientific examination, showing notable promise for implementation in next-generation flexible electronics tailored to wearable technologies. Nevertheless, the uneven dispersion of carbon nanoparticles is the key to hindering the stretchability, high elasticity, and electrical conductivity of the material. Herein, ionic liquid 1-vinyl- 3-butyl imidazole bromide ([VBlm]Br) and polyacrylamide/sodium alginate (PAM/SA) were selected to form a new copolymerized hydrogel to improve the dispersion of conductive graphite (KS- 6) in the hydrogel. Due to the existence of an electron–ion conducting network and spatial cross-linking, making the prepared KS- 6/1.0[VBlm]Br/PAM/SA hydrogelhas good conductivity (22.39 mS/cm), tensile strain (467%), mechanical strength (73.64 kPa), toughness (161.09 kJ m −3 ), and adhesion (67.861 kPa). In addition, the flexible sensor based on the KS- 6/1.0[VBlm]Br/PAM/SA hydrogel also showed excellent performance, demonstrating that ionic liquids and carbon materials can synergistically enhance mechanical properties and electrical conductivity. The high-temperature sensing performance and high sensitivity (GF = 4.01) make the KS- 6/1.0[VBlm]Br/PAM/SA hydrogel an ideal candidate for building the next generation of gel-based strain sensor platforms.

Health benefits and digestive properties of Ca2+-regulated sodium alginate from an endogenous method in buckwheat noodles

Lingyu Han,Nuo Dong,Jixin Yang,Bing Hu

The present study investigated the impact of Ca 2+ regulated sodium alginate gelation on buckwheat noodle digestion, as well as its physiological and biochemical effects on rat. An endogenous method was employed for noodle preparation, and the rate of starch hydrolysis was evaluated. Buckwheat noodles prepared using this approach exhibited significantly reduced rates of starch digestion compared to conventional methods. Increased concentrations of sodium alginate and Ca 2+ led to the formation of dense gel networks that promoted weight gain in diabetic rats while simultaneously lowering postprandial blood glucose levels and improving glucose intolerance and abnormal insulin tolerance. Moreover, these gel networks enhanced liver glycogen synthesis by increasing SOD and CAT activities while reducing the levels of ALT and MDA, thereby mitigating morphological damage in the liver. Buckwheat noodles prepared using this endogenous method were found to potentially exhibit hypoglycemic effects and mitigate complications associated with type 2 diabetes.

Preparation of sodium alginate microspheres reinforced with oxidized and regenerated cellulose and investigation of their encapsulation properties

Zhang Qian,Hao Sufen,Zhang Wenrui,Ding Zitian,Wang Xin,Huang Jintian

This paper presents a novel inside-out, layer-by-layer assembly process that combines the sol–gel transphase with pH inversion to prepare cellulose-reinforced sodium alginate (SA) gel microspheres (Q-ACCs). The use of oxidized cellulose (TOCN) in the inner layer resulted in a petal-like morphology and increased the specific surface area of the microspheres. The outermost layer of regenerated cellulose (RC) improved the mechanical properties and water absorption capacity of the hydrogel microspheres. Notably, the microspheres exhibited good encapsulation properties. Remarkable results were achieved when encapsulating fertilizer and Fe 3 O 4 . This study offers promising prospects for the preparation of gel microspheres and the development of functional synergies for producing multifunctional encapsulated materials in various fields. Graphical abstract

Polyvinyl alcohol/sodium alginate composite sponge with 3D ordered/disordered porous structure for rapidly controlling noncompressible hemorrhage

Pengpeng Li,Lina Cao,Feng Sang,Bingxu Zhang,Zhizhen Meng,Lingling Pan,Jiahui Hao,Xiao Yang,Zhaipu Ma,Changcan Shi

It is still a challenge to develop a sponge that can efficiently control noncompressible bleeding to meet the emergency treatment and clinical demand. Herein, we combined the 3D printing sacrificial template method and freeze-drying technology to prepare polyvinyl alcohol/sodium alginate (PVA/SA) composite sponges with ordered microchannels and disordered porous structure. Compared with conventional sponges, the prepared sponge showed ultra-rapid water/blood absorption capacity and satisfactory mechanical properties. Furthermore, when the sponge was stuffed into a noncompressible wound and contacted with blood, it could accurately guide and quickly absorb a large amount of blood through the microchannels. Moreover, the platelets, red blood cells and coagulation factors would be enriched in the microchannels and microporous structure. In the SD rat liver noncompressible hemorrhage and femoral artery puncture injury model, PVA-SA composite sponge with 3D ordered/disordered porous structure showed enhanced hemostatic performance compared with commercial MPVA sponges. Depend on the special ordered/disordered porous structure, PVA-SA composite sponge could accelerate the blood convergence and promote coagulation. This design of special porous structure opened up a new avenue to develop hemostatic sponges for rapidly controlling noncompressible hemorrhage.

Selective adsorption and separation of Cr(VI) by surface-imprinted microsphere based on thiosemicarbazide-functionalized sodium alginate

Yapei Luo,Heng Li,Minghua Wu,Wei Wang,Lili Wang

A Spray-Filming Self-Healing Hydrogel Fabricated from Modified Sodium Alginate and Gelatin as a Bacterial Barrier

Yan Du,Lin Li,Haitao Peng,Heng Zheng,Shuang Cao,Guoyu Lv,Aiping Yang,Hong Li,Tielong Liu

Self-healing hydrogels as wound dressings still face challenges in infection prevention, especially in the dressing of mass wounds, due to their inflexibility and the slow formation of the protective film on the wound. Therefore, designing a spray-filming (rapid-forming) hydrogel that can serve as a bacterial barrier is of particular significance in the development of wound dressings. Here, a self-healing hydrogel based on adipic acid dihydrazide-modified gelatin (Gel-ADH) and monoaldehyde-modified sodium alginate(SA-mCHO) is prepared. Using dynamic, Schiff base bonds, the hydrogels exhibit excellent self-healing properties. Moreover, the gelation time of SA-mCHO/Gel-ADH (SG) hydrogels is shortened to 2–21 s, resulting in rapid filming by spraying the two precursor solutions. In addition, the rapid spray-filming ability might offer sufficient flexibility and rapidity for dealing with mass and irregular wounds. Notably, the bacterial barrier experiments show that the SG hydrogel films could form an effective barrier to Staphylococcus aureus and Candida albicans for 12 h. Therefore, SG hydrogels could be used in wound dressings and they show great promise in applications associated with mass and irregular traumas.

Construction of sustainable fully bio-based sodium alginate composite aerogels for advanced thermal insulation and fire protection

Zhennan Wang,Guoping Zhu,Yu Huang,Yadong Wang,Zongmin Zhu

Biomass aerogels have attracted considerable attention in the field of building thermal insulation due to their low thermal conductivity and environmental friendliness. However, achieving biomass aerogels with both excellent flame retardancy and low thermal conductivity remains a significant challenge. In this study, a fully bio-based flame-retardant aerogel was constructed with sodium alginate, tannic acid and phytic acid as raw materials. The prepared aerogels exhibit a limiting oxygen index (LOI) exceeding 60 % and achieve a V-0 rating in the UL-94 vertical burning test. It demonstrates an ultra-low total heat release of 1.5 MJ/m 2 and a smoke release value of 0.97 m 2 , along with a low thermal conductivity of 0.039 W·m −1 ·K −1 . To further improve the environmental stability, the aerogel was hydrophobically modified using MTMS via a simple CVD process, endowing it with enhanced water resistance and interfacial durability. Furthermore, the synergistic interaction between tannic acid and phytic acid significantly enhances the mechanical properties of the aerogel. This study offers a novel design strategy and theoretical foundation for the development of green, efficient, bio-based gas barrier aerogel materials.

Synergistic Effect of Sodium Alginate and Lignin on the Properties of Biodegradable Poly(vinyl alcohol) Mulch Films

Weiyi Su,Zhiwei Yang,Haoyang Wang,Jing Fang,Chunli Li,Gaojin Lyu,Hao Li

Replacing petrochemical polymers with biomaterials for biodegradable mulch applications has attracted widespread attention. However, improving film performance and reducing costs remain an issue. In this work, we found that the synergistic effect of sodium alginate and quaternary lignin significantly improved the performance and reduced the cost of poly(vinyl alcohol) films. The water retention, ultraviolet (UV) resistance, heat collection, light transmission, mechanical properties, soil consolidation, and the degradation rates of the composite films were systematically studied. We found that the addition of lignin enabled the film to achieve complete UV resistance, while the sodium alginate synergistically improved the mechanical and water-holding properties of the film. The film improved soil slumping, and the water vapor permeability of the film was 109.2 g·m–2·day–1. The degradation of the film was facilitated by the self-degradation properties of sodium alginate and lignin, which degraded 55% after 50 days.

Shape-recoverable chitosan/sodium alginate aerogels with sustained oxygen release and antibacterial activity for diabetic wound healing

Zhihao Lin,Jiaojiao Jia,Chengzhi Liang,Yueyan Ma,Hao Liu,Kuanjun Fang,Yanling Hu

Wounds in diabetic patients are often inhibited in angiogenesis and extracellular matrix synthesis due to insufficient oxygen supply, leading to prolonged healing time. Although oxygen therapy has been shown to promote the healing of chronic wounds, its therapeutic effectiveness remains limited by high costs, complex procedures, and a lack of sustainability. In this study, we developed an aerogel composed of chitosan (CS), sodium alginate (SA), and calcium peroxide (CPO). These aerogels can absorb wound exudate and release oxygen upon contact, providing continuous oxygen delivery for over five days. The freeze-dried aerogels are soft and exhibit shape recovery properties, which facilitate enhanced oxygen transport. Furthermore, the CS/SA-CPO aerogel demonstrated strong antioxidant activity, excellent biocompatibility, and potent antibacterial properties (exceeding 99.99 %). In vivo experiments indicated that the CS/SA-CPO aerogel promotes wound healing by continuously releasing oxygen, accelerating collagen deposition, and enhancing re-epithelialization, ultimately achieving 99.65 % wound closure within 21 days. This innovative approach offers a promising strategy for managing chronic, hypoxic diabetic wounds.