Nanocomposite Polymer Electrolytes of Sodium Alginate and Montmorillonite Clay

Nanocomposite polymer electrolytes (NPEs) were synthesized using sodium alginate (Alg) and either sodium (SCa-3-Na⁺)- or lithium (SCa-3-Li⁺)-modified montmorillonite clays. The samples were characterized by structural, optical, and electrical properties. SCa-3-Na⁺ and SCa-3-Li⁺ clays’ X-ray structural analyses revealed peaks at 2θ = 7.2° and 6.7° that corresponded to the interlamellar distances of 12.3 and 12.8 Å, respectively. Alg-based NPEs X-ray diffractograms showed exfoliated structures for samples with low clay percentages. The increase of clay content promoted the formation of intercalated structures. Electrochemical Impedance Spectroscopy revealed that Alg-based NPEs with 5 wt% of SCa-3-Na⁺ clay presented the highest conductivity of 1.96 × 10⁻² S/cm², and Alg with 10 wt% of SCa-3-Li⁺ showed conductivity of 1.30 × 10⁻² S/cm², both measured at 70 °C. From UV-Vis spectroscopy, it was possible to infer that increasing concentration of clay promoted a decrease of the samples’ transmittance and, consequently, an increase of their reflectance.     

交联聚(N-异丙基丙烯酰胺)/(海藻酸钠/聚(N-异丙基丙烯酰胺))半互穿网络水凝胶的制备及其溶胀性能

将线性聚(N-异丙基丙烯酰胺)(PNIPAAm)和海藻酸钠(SA)分子同时引入到PNIPAAm凝胶中,制备了交联聚(N-异丙基丙烯酰胺)/(海藻酸钠/聚(N-异丙基丙烯酰胺))半互穿网络(Cr-PNIPAAm/(SA/PNIPAAm)semi-IPN)水凝胶。在弱碱性条件下(pH=7.4),改变SA与线性PNIPAAm的质量比对Cr-PNIPAAm/(SA/PNIPAAm)semi-IPN水凝胶的溶胀度没有太大的影响。在酸性条件下(pH=1.0),其溶胀度随着SA与线性PNIPAAm质量比的减小而增大。由于亲水性SA与线性PNIPAAm的协同作用,Cr-PNIPAAm/(SA/PNIPAAm)semi-IPN水凝胶的消溶胀速率得到很大提高。     

Encapsulation of Bromelain in Combined Sodium Alginate and Amino Acid Carriers: Experimental Design of Simplex-Centroid Mixtures for Digestibility Evaluation

Bromelain has potential as an analgesic, an anti-inflammatory, and in cancer treatments. Despite its therapeutic effects, this protein undergoes denaturation when administered orally. Microencapsulation processes have shown potential in protein protection and as controlled release systems. Thus, this paper aimed to develop encapsulating systems using sodium alginate as a carrier material and positively charged amino acids as stabilizing agents for the controlled release of bromelain in in vitro tests. The systems were produced from the experimental design of centroid simplex mixtures. Characterizations were performed by FTIR showing that bromelain was encapsulated in all systems. XRD analyses showed that the systems are semi-crystalline solids and through SEM analysis the morphology of the formed systems followed a pattern of rough microparticles. The application of statistical analysis showed that the systems presented behavior that can be evaluated by quadratic and special cubic models, with a p-value < 0.05. The interaction between amino acids and bromelain/alginate was evaluated, and free bromelain showed a reduction of 74.0% in protein content and 23.6% in enzymatic activity at the end of gastric digestion. Furthermore, a reduction of 91.6% of protein content and 65.9% of enzymatic activity was observed at the end of intestinal digestion. The Lis system showed better interaction due to the increased stability of bromelain in terms of the amount of proteins (above 63% until the end of the intestinal phase) and the enzymatic activity of 89.3%. Thus, this study proposes the development of pH-controlled release systems aiming at increasing the stability and bioavailability of bromelain in intestinal systems.     

Gel Polymer Electrolytes with Talc as a Natural Mineral Filler and a Biodegradable Polymer Matrix in Sodium-Ion Batteries

A gel polymer electrolyte based on poly(vinyl alcohol) (PVA) is used in sodium-ion batteries (SIBs). The use of biodegradable and water-soluble polymer potentially reduces the negative environmental impact. The other components include sodium salt (NaPF₆), sulfolane (TMS) as a plasticizer and talc. For the first time, natural and abundant talc has been used as an inert filler in a gel polymer electrolyte. The best results were obtained for moderate amounts of filler (1 and 3 wt%). Then, an increase in the conductivity, transference numbers, and thermal stability of the membranes was observed. Moreover, the presence of talc had a positive effect on the cyclability of the hard carbon electrode. The discharge capacity after 50 cycles of HC|1 % T_TMS|Na and HC|3 % T_TMS|Na was 243 and 225 mAh g⁻¹, respectively. The use of talc in gel polymer electrolytes containing sodium ions improves the safety and efficiency of SIBs.     

海藻酸钠的疏水改性及在药物控释中的应用

海藻酸盐是一种由β-D-甘露糖酸盐(M)和α-L-古罗糖酸盐(G)连接而成的天然高分子,广泛存在于各类棕色海藻中,可与多价阳离子形成凝胶,成胶条件温和,该凝胶在生物体内以酶解方式生成甘露糖醛酸和葡萄糖醛酸,对机体无毒性、无免疫原性,适合作为释放或包埋药物、蛋白质与细胞的微胶囊.     

One‐Step Microfluidic Coating of Phospholipid Microbubbles with Natural Alginate Polymer as a Delivery System for Human Epithelial Lung Adenocarcinoma

In this study, the neoplastic drug frequently used in the treatment of lung cancer, carboplatin is loaded to microbubbles via a microfluidic platform. In order to increase the drug loading capacity of microbubbles, carboplatin is encapsulated into alginate polymer layer. The phospholipid microbubbles (MBs) are synthesized by MicroSphere Creator, which is connected with T‐junction and micromixer for the treatment with CaCl₂ solution to provide gelation of the alginate coated phospholipid microbubbles (AMBs). The carboplatin loaded alginate coated phospholipid microbubbles (CAMBs) result in 12.2 ± 0.21 µm mean size, obtained by mixing with 0.05% CaCl₂ using T‐junction. The cytotoxic activities of the synthesized MBs, AMBs, and CAMBs are also investigated with the 3‐(4,5‐Dimethyl‐2‐thiazolyl)‐2,5‐diphenyl‐2H‐tetrazolium bromide) (MTT) and live/dead fluorescent dying assays in the A549 and BEAS‐2B cell lines. The one‐step microfluidic coating of lipid microbubbles with natural alginate polymer appears to be a promising strategy for enhanced drug reservoir properties.     

Study of Complex Coacervation of Gelatin A and Sodium Alginate for Microencapsulation of Olive Oil

Complex coacervation of gelatin A and sodium alginate was carried out to obtain the maximum coacervate yield. Turbidity and coacervate yield (%) measurements were carried out to support the ratio of the two polymers and pH that produced maximum coacervation. The optimum ratio between gelatin A-sodium alginate and pH to form the maximum coacervate complex was found to be 3.5:1 and 3.5–3.8, respectively. Olive oil microencapsulation was carried out at the optimized ratio and pH. Microcapsules were crosslinked by using glutaraldehyde. Scanning electron microscopy studies confirmed the formation of free flowing spherical microcapsules of different sizes. The size of microcapsules increased with the increase in the concentration of the polymer. The encapsulation efficiency and the release rates of olive oil were dependent on the amount of crosslinker, oil loading and polymer concentration. Thermogravimetric study revealed improvement of thermal stability with crosslinking. Fourier Transform Infrared Spectroscopy study showed that there was no significant interaction between olive oil and gelatin-alginate complex.     

辣根过氧化物酶在海藻酸钠水凝胶中的电化学和电催化特性

辣根过氧化物酶在海藻酸钠水凝胶中的电化学和电催化特性;辣根过氧化物酶;海藻酸钠;直接电化学电;催化     

Physicochemical,Structural, and In Vitro Gastrointestinal Tract Release Properties of Sodium Alginate-Based Cryogel Beads Filled with Hydroxypropyl Distarch Phosphate as a Curcumin Delivery System

The objectives of this study were to produce sodium alginate (SA)-based cryogel beads filled with different concentrations (0, 0.4, 1.0, and 2.5%, w/w) of hydroxypropyl distarch phosphate (HDP) as a curcumin delivery system and to investigate the physicochemical, structural, and in vitro gastrointestinal tract release properties of the cryogel beads. According to FT-IR analysis, the formation of ionic crosslinking between SA and Ca²⁺ and the presence of HDP were found. XRD analysis demonstrated the successful encapsulation of curcumin in the beads by observing the disappearance of the characteristic peaks of curcumin. SEM analysis results revelated that SA-based cryogel beads exhibited a denser internal structure as the HDP concentration was increased. The encapsulation efficiency of curcumin in SA cryogel beads filled with HDP concentration from 0% to 2.5% was increased from 31.95% to 76.66%, respectively, indicating that HDP can be a suitable filler for the encapsulation of curcumin in the production of SA-based cryogel beads. After exposure to simulated gastric fluid (SGF) and simulated intestinal fluid (SIF), the release rate of curcumin was decreased as HDP concentration was increased. Accordingly, SA-based cryogel beads filled with HDP can be utilized for the delivery system of curcumin in the food industry.     

Microencapsulation of DNA Within alginate microspheres and crosslinked chitosan membranes for in vivo application

Calf thymus DNA was microencapsulated within crosslinked chitosan membranes, or immobilized within chitosan-coated alginate microspheres. Microcapsules were prepared by interfacial polymerization of chitosan, and alginate microspheres formed by emulsification/ internal gelation. Diameters ranged from 20 to 500 Μm, depending on the formulation conditions. Encapsulated DNA was quantifiedin situ by direct spectrophotometry (260 nm) and ethidium bromide fluorimetry, and compared to DNA measurements on the fractions following disruption and dissolution of the microspheres. Approximately 84% of the DNA was released upon core dissolution and membrane disruption, with 12% membrane bound. The yield of encapsulation was 96%. Leakage of DNA from intact microspheres/capsules was not observed. DNA microcapsules and microspheres were recovered intact from rat feces following gavage and gastrointestinal transit. Higher recoveries (60%) and reduced shrinkage during transit were obtained with the alginate microspheres. DNA was recovered and purified from the microcapsules and microspheres by chromatography and differential precipitation with ethanol. This is the first report of microcapsules or microspheres containing biologically active material (DNA) being passed through the gastrointestinal tract, with the potential for substantial recovery.     

Development of Biopolymer Based Matrix Type Multiple Unit Systems for Sustained Release of Diclofenac Sodium: In vitro and In vivo Evaluation

The objective of the present study was to investigate the applicability of matrix type chitosan treated alginate multiple unit systems (MUS) for sustained release of diclofenac sodium. The multiple unit systems (MUS) were prepared by the ionotropic gelation method. Spherical MUS with 1.852±0.041–2.173±0.265 mm diameter range and 66.66±3.21 to 78.55±6.49% entrapment efficiency were produced. The addition of chitosan increased the swelling of MUS in acidic conditions and reduced the drug release from MUS. The fluoroscopic study reveals that the MUS retained in gastrointestinal tract (GIT) for more than 12 h and distributed throughout the GIT. The in vivo evaluation in healthy human volunteers of the MUS and that of Voveran SR tablets each containing 100 mg drug revealed that the MUS was bioequivalent to Voveran SR producing a non‐significantly different (p>0.05) AUC. This study demonstrates that the matrix type chitosan treated alginate MUS can be a good alternative to sustained release tablets to deliver diclofenac sodium and expected to be less of an irritant to gastric and intestinal mucosa.     

A Fast Made Disposable Glucose Biosensor Incorporating the Oxidase and a Ferrocene in an Alginate Gel

Abstract

A simple procedure is described for co-immobilization of glucose oxidase and dimethylaminomethylferrocene in a sodium alginate gel on the surface of pyrolytic graphite electrode. The film is electrochemically active and the peak current is a function of D-glucose concentration with the apparent Michaelis-Menten constant K_m = (1.2±0.3) × 10^?2 M. The optimal concentration range for biosensoric applications in 0.001–0.010 M.

     

Phospholipid Polymer Hydrogel Matrices with Dually Immobilized Cytokines for Accelerating Secretion of the Extracellular Matrix by Encapsulated Cells

Construction of 3D tissues by various types of cells with specific characteristics is an important and fundamental technology in tissue reconstruction medicine and animal‐free diagnosis system. To do so, an excellent extracellular matrix (ECM) is needed for encapsulation of cells and maintaining cell activity. Spontaneously forming hydrogel matrix is used by complexation between two water‐soluble polymers, 2‐methacryloyloxyethyl phosphorylcholine polymer bearing phenylboronic acid groups and poly(vinyl alcohol). Two cytokines for cell proliferation are immobilized in the hydrogel matrix to control the activities of the encapsulated cells. The cytokine‐immobilized hydrogel matrix can encapsulate both L929 fibroblasts and normal human dermal fibroblasts under mild condition. The physical properties of the hydrogel matrix can follow the proliferation process of the encapsulated cells. The encapsulated cells secrete ECM in the polymer hydrogel networks upon 3D culturing for 7 days. Consequently, the tissue‐mimicking ECM hybrid hydrogels are fabricated successfully.     

Examination of the Higuchi Model for the Release of Vitamin B2 from Multilayered Calcium Alginate/Chitosan Beads in Varying pH Medium

The release of model drug vitamin B₂ from calcium alginate/chitosan multi‐layered beads has been studied in the media of varying pH (3 h in the medium of pH 1.0 and for the remaining time in pH 7.4) at 37°C. The quantitative deviation of experimental data from the Higuchi model has been interpretated by using a newly developed ‘curve area measurement’ (CAM) approach. The higher deviation in the initial phase has been explained on the basis of porous structure of beads due to the use of low molecular weight polymers in the preparation of beads.     

Polysaccharide Hydrogels for the Protection of Dairy-Related Microorganisms in Adverse Environmental Conditions

Adverse environmental conditions are severely limiting the use of microorganisms in food systems, such as probiotic delivery, where low pH causes a rapid decrease in the survival of ingested bacteria, and mixed-culture fermentation, where stepwise changes and/or metabolites of individual microbial groups can hinder overall growth and production. In our study, model probiotic lactic acid bacteria (L. plantarum ATCC 8014, L. rhamnosus GG) and yeasts native to dairy mixed cultures (K. marxianus ZIM 1868) were entrapped in an optimized (cell, alginate and hardening solution concentration, electrostatic working parameters) Ca-alginate system. Encapsulated cultures were examined for short-term survival in the absence of nutrients (lactic acid bacteria) and long-term performance in acidified conditions (yeasts). In particular, the use of encapsulated yeasts in these conditions has not been previously examined. Electrostatic manufacturing allowed for the preparation of well-defined alginate microbeads (180–260 µm diameter), high cell-entrapment (95%) and viability (90%), and uniform distribution of the encapsulated cells throughout the hydrogel matrix. The entrapped L. plantarum maintained improved viabilities during 180 min at pH 2.0 (19% higher when compared to the free culture), whereas, L. rhamnosus appeared to be less robust. The encapsulated K. marxianus exhibited double product yields in lactose- and lactic acid-modified MRS growth media (compared to an unfavorable growth environment for freely suspended cells). Even within a conventional encapsulation system, the pH responsive features of alginate provided superior protection and production of encapsulated yeasts, allowing several applications in lacto-fermented or acidified growth environments, further options for process optimization, and novel carrier design strategies based on inhibitor charge expulsion.     

石墨烯在防腐薄膜和有机防腐涂层领域的理论和应用研究综述

归纳和整理了关于石墨烯防腐薄膜和有机防腐涂层的国内外文献,形成了具有层次和条理的知识结构.综述了石墨烯防腐薄膜的制备、优化改进,讨论了其应用中所面临的腐蚀加速问题和解决方法.根据石墨烯在有机防腐涂层中所起到的作用,从应用研究和理论研究角度,综述了石墨烯基复合材料对有机防腐涂层屏蔽性、结合力、自修复作用的改进,以及对阴极保护型有机防腐涂层电化学保护性能的改进.     

海藻酸钠溶液溶胶－凝胶相转移的温度效应及IR光谱研究

考察了３ｗｔ％海藻酸钠溶液中加入Ｃｕ２＋、Ｃｏ２＋后，体系的粘度、电导与离子浓度、温度的关系，结合ＩＲ光谱对海藻酸钠溶液在溶胶－凝胶相转移过程中的分子结构与构型变化进行了解剖。     

海藻酸盐水凝胶在食品、医药和环保中的应用综合实验*

从奶茶中流行的爆爆珠的制作入手,通过精巧的实验设计,引导学生探究海藻酸盐水凝胶在医药和环境治理领域的多维应用。该实验深浅兼备,源于生活,契合公众关注的环境和医药热点,同时结合原创动画视频深入浅出地介绍了水凝胶的形成和药物缓释等相关原理。     

Use of Graphite as a Highly Reversible Electrode with Superior Cycle Life for Sodium‐Ion Batteries by Making Use of Co‐Intercalation Phenomena

Although being the standard anode material in lithium‐ion batteries (LIBs), graphite so far is considered to fail application in sodium‐ion batteries (NIBs) because the Na‐C system lacks suitable binary intercalation compounds. Here we show that this limitation can be circumvented by using co‐intercalation phenomena in a diglyme‐based electrolyte. The resulting compound is a stage‐I ternary intercalation compound with an estimated stoichiometry of Na(diglyme)₂C₂₀. Highlights of the electrode reaction are its high energy efficiency, the small irreversible loss during the first cycle, and a superior cycle life with capacities close to 100 mAh g^?1 for 1000 cycles and coulomb efficiencies >99.87 %. A one‐to‐one comparison with the analogue lithium‐based cell shows that the sodium‐based system performs better and also withstands higher currents.     

Boronate Affinity Monolith with a Gold Nanoparticle‐Modified Hydrophilic Polymer as a Matrix for the Highly Specific Capture of Glycoproteins

As low abundance is the great obstacle for glycoprotein analysis, the development of materials with high efficiency and selectivity for glycoprotein enrichment is a prerequisite in glycoproteome research. Herein, we report a new kind of hydrophilic boronate affinity monolith by attaching 4‐mercaptophenylboronic acid (MPBA) with 2‐mercaptoethylamine (MPA) on the gold nanoparticle‐modified poly(glycidyl methacrylate‐co‐poly(ethylene glycol) diacrylate)) monolith for glycoprotein enrichment. With poly(ethylene glycol) diacrylate as the cross‐linker and the further modification of gold nanoparticles, the matrix has advantages of good hydrophilicity and enhanced surface area, which are beneficial to improve the enrichment selectivity and efficiency for glycoproteins. The attachment of MPBA and MPA provide intramolecular B?N coordination, which could further enhance the specificity of glycoprotein capture. Such a boronate affinity monolith was applied to enrich horseradish peroxidase (HRP) from the mixture of HRP and bovine serum albumin (BSA), and high selectivity was obtained even at a mass ratio of 1:1000. In addition, the binding capacity of ovalbumin on such monolith reached 390 μg g^?1. Furthermore, the average recovery of HRP on the prepared affinity monoliths was (84.8±1.9) %, obtained in three times enrichment with the same column. Finally, the boronate affinity monolith was successfully applied for the human‐plasma glycoproteome analysis. As a result, 160 glycoproteins were credibly identified from 9 μg of human plasma, demonstrating the great potential of such a monolith for large‐scale glycoproteome research.