微乳液凝胶固定化技术及在生物传感器领域中的应用

利用微乳液胶凝现象来固定化酶是20世纪90年代初建立起来的酶固定化新技术，该技术为胶束酶学在生物合成与转化领域的应用奠定了基础。对微乳液凝胶固定化技术及微乳液凝胶在生物传感器领域的应用做了综述。并对微乳液凝胶技术应用于非水相传感器领域进行了展望。     

Synthesis and Characterization of Phosphonic-Acrylic Organogels

Polymeric organogels based on vinyl phosphonic acid (VPA) and acrylic monomers such as 2-acrylamido 2-methyl propane sulfunic acid (AMPS) and acrylamide (AM) were prepared. The synthesized poly (AMPS-VPA) organgels can absorb ethanol (12.64–31.2 g/g) and methanol (17.65–32.32 g/g). Poly (AM-VPA) can absorb DMSO (4.05–8.94 g/g). TGA analysis showed that thermal stability of organogels was improved with enhancement of VPA content. This was attributed to presence of phosphorus in the polymer structure. Rheological behavior exhibited that gel strength was decreased with higher VPA content in copolymeric structures.     

Improved initial burst of estradiol organogel as long-term in situ drug delivery implant: formulation,in vitro and in vivo characterization

Objective: The present investigation was aimed at optimizing of estradiol (E2) loaded l-amino acid derivatives organogel formulations resulting in improved the high initial release problems and sustained release of E2.

Methods: The visco-elastic properties of blank organogels were measured by rheometer. The E2 organogel formulations were optimized using a central composite design. Also, the effect of gelator structure and composition of the gel formulations on release behavior (in vitro and in vivo) had been studied.

Results: The change of the gelator structure could affect significantly the stiffness of the implants. The release behavior of gel without N-Methyl-2-pyrrolidinone (NMP) was controlled by gel corrosion only. While the drug release of the gel with NMP was controlled by both corrosion and diffusion. The high initial release problems of the organogels were improved by optimizing the formulations. The system consisting by N-Lauroyl l-lysine methyl ester (LLM) derivative in the oil indicated the lowest initial drug release, showed a much lower blood drug level and maintained a steady state for nearly 1 month.

Conclusion: Organogels based on l-lysine methyl ester derivative were ideal carriers for long-term parenteral administration of E2.     

吡啶二酰胺类凝胶因子的合成及性能

合成了系列不同侧链的吡啶二酰胺类衍生物4a、4b、4c、5、9。测试并对比了其凝胶性能,结果表明该类化合物在有机溶剂中具有较好的凝胶性能且侧链对其性能具有很大影响。通过紫外光谱及红外光谱测试研究了系列化合物的成胶驱动力;阴离子测试结果表明该系列凝胶具有阴离子响应特性,同时验证了氢键作用的存在。运用扫描电子显微镜观察并分析了凝胶的微观形貌。计算了凝胶因子9和8种溶剂的梯氏参数,绘制了相应的梯氏参数图,并对预测成胶区域的有效性进行了验证。     

利用蒸馏单硬脂酸甘油酯制备玉米胚芽油基凝胶油的研究

以玉米胚芽油为原料、蒸馏单硬脂酸甘油酯为凝胶因子,利用加热搅拌和冷却方法制备玉米胚芽油基凝胶油,研究不同工艺条件对玉米胚芽油基凝胶油硬度的影响。结合单因素实验和正交实验优化得到玉米胚芽油基凝胶油最佳制备工艺条件为:蒸馏单硬脂酸甘油酯添加量8%,加热温度90℃,加热时间45 min,搅拌速率200 r/min,冷却温度5℃。在最佳工艺条件下,玉米胚芽油基凝胶油硬度为2.69 N、黏度力为4.08 N、持油率为99.971%。     

Novel carbon‐nanotube‐based organogels as candidates for oil recovery

A simple method for synthesis of novel organogels based on multiwalled carbon nanotubes (MWCNTs) is reported. Three classes of organogels were synthesized by crosslinking polymerization of dodecyl methacrylate with various weight percentages of 1,4‐butanediol dimethacrylate, vinyl‐group‐modified MWCNTs or pristine MWCNTs in the presence of 2,2‐azoisobutyronitrile as initiator. In this reaction, the carbon nanotubes (CNTs) served simultaneously as an adsorbent, a comonomer and a crosslinking agent. The oil‐absorbent containing CNTs showed much higher swelling capacity in oil and organic solvents compared with that without CNTs. Therefore, CNT‐based organogels can be introduced as a promising candidate for environmental protection and oil recovery. © 2012 Society of Chemical Industry     

Homogeneous Freestanding Luminescent Perovskite Organogel with Superior Water Stability

Metal‐halide perovskites have become appealing materials for optoelectronic devices. While the fast advancing stretchable/wearable devices require stability, flexibility and scalability, current perovskites suffer from ambient‐environmental instability and incompatible mechanical properties. Recently perovskite?polymer composites have shown improved in‐air stability with the protection of polymers. However, their stability remains unsatisfactory in water or high‐humidity environment. These methods also suffer from limited processability with low yield (2D film or beads) and high fabrication cost (high temperature, air/moisture‐free conditions), thereby limiting their device integration and broader applications. Herein, by combining facile photo‐polymerization with room‐temperature in‐situ perovskite reprecipitation at low energy cost, a one‐step scalable method is developed to produce freestanding highly‐stable luminescent organogels, within which CH₃NH₃PbBr₃ nanoparticles are homogeneously distributed. The perovskite‐organogels present a record‐high stability at different pH and temperatures, maintaining their high quantum yields for > 110 days immersing in water. This paradigm is universally applicable to broad choices of polymers, hence casting these emerging luminescent materials to a wide range of mechanical properties tunable from rigid to elastic. With intrinsically ultra‐stretchable photoluminescent organogels, flexible phosphorous layers were demonstrated with > 950% elongation. Rigid perovskite gels, on the other hand, permitted the deployment of 3D‐printing technology to fabricate arbitrary 2D/3D luminescent architectures.     

Factors influencing the erosion rate and the drug release kinetics from organogels designed as matrices for oral controlled release of a hydrophobic drug

Abstract

This article proposes solid-like systems from sunflower oil structured with a fibrillar network built by the assembly of 12-hydroxystearic acid (12-HSA), a gelator molecule for an oil phase. The resulting organogels were studied as oral controlled release formulations for a lipophilic drug, Efavirenz (EFV), dissolved in the oil. The effects of the gelator concentration on the thermal properties of the organogels were studied by Differential Scanning Calorimetry (DSC) and showed that drug incorporation did not change the sol–gel–sol transitions. The erosion and drug release kinetics from organogels under conventional (filling gelatin capsules) or multiparticulate (beads obtained by prilling) dosage forms were measured in simulated gastric and intestinal fluids. EFV release profiles were analyzed using model-dependent (curve-fitting) and independent approaches (Dissolution Efficiency DE). Korsmeyer–Peppas was the best fitting release kinetic model based on the goodness of fit, revealing a release mechanism from organogels loaded with EFV different from the simple drug diffusion release mechanism obtained from oily formulations. From organogels, EFV probably diffuses through an outer gel layer that erodes releasing oil droplets containing dissolved EFV into the aqueous medium.     

Properties of Cookies Made with Natural Wax–Vegetable Oil Organogels

The aim of this study was to examine the feasibility of cookies in which the conventional margarine is replaced with an organogel of vegetable oil (VO) and natural wax. New cookies from VO organogels contain no trans fats and much less saturated fats than cookies made with a conventional margarine. To understand the effects of different kinds of waxes, organogels were prepared from 4 different waxes including sunflower wax (SW), rice bran wax (RBW), beeswax, and candelilla wax and properties of cookie dough and cookie were evaluated. To investigate the effects of different VOs on the properties of cookies, 3 VOs including olive oil, soybean oil and flaxseed oil representing oils rich in oleic acid (18:1), linoleic acid (18:2), and linolenic acid (18:3), respectively, were used. Both the wax and VO significantly affected properties of organogel such as firmness and melting behavior shown in differential scanning calorimetry. The highest firmness of organogel was observed with SW and flaxseed oil. Properties of dough such as hardness and melting behavior were also significantly affected by wax and VO while trends were somewhat different from those for organogels. SW and RBW provided greatest hardnesses to cookie dough. However, hardness, spread factor, and fracturability of cookie containing the wax–VO organogel were not significantly affected by different waxes and VOs. Several cookies made with wax–VO organogels showed similar properties to cookies made with a commercial margarine. Therefore, this study shows the high feasibility of utilization of the organogel technology in real foods such as cookies rich in unsaturated fats.     

Structuring of edible oils by long-chain FA,fatty alcohols,and their mixtures

Homologous series of fatty alcohols and FA with chain lengths ranging from 16 to 22 carbons were evaluated for their oil-structuring potential by texture profile analysis (TPA). FA, fatty alcohols, and their mixtures were found to structure sunflower oil and several vegetable oils at levels as low as 2% (w/w) for the pure ingredients. Mixtures of fatty alcohols and FA with the same chain lengths, at 5% (w/w) in sunflower oil, showed a synergistic effect below 20°C at the composition ratios of 7∶3 and 3∶7 (w/w). This synergistic effect in the 7∶3 stearyl alcohol/stearic acid mixture was due to effects on the microstructure of the composite material. The larger number of small crystals observed in the mixture was attributed to effects on the crystallization kinetics as a result of minimal interfacial tension at the specific 1∶3 and 3∶1 molecular ratios.