Designing Gelatin Based Blood Compatible Materials with Hydrophilic and Hydrophobic Macromolecular Chains

Polymer matrices based on poly 2-hydroxyethyl methacrylate (PHEMA) have emerged as promising materials for developing applications in biomedical and tissue engineering fields. The major criteria of a material to be used as a support matrix in tissue engineering application rests on its biocompatible, hydrophilic, and mechanically strong nature. Although a great deal of research efforts have been put into designing such materials, achieving these properties together for such a material still remains a challenge. Thus, by a judicious combination of natural and synthetic polymers, such as gelatin and copolymers of PHEMA and PAN, respectively, it has been attempted to synthesize a polymer material by redox polymerization method. The prepared polymer matrix was characterized by FTIR, scanning electron microscopy (SEM), and differential scanning calorimetry (DSC) techniques. The prepared polymeric biomaterials were assessed for their water sorption potential under varying experimental conditions such as chemical composition, pH, and temperature of the swelling bath. The diffusion mechanism of transport of water molecules arising due to solvent–polymer interaction was analyzed to predict the behavior of continuously relaxing macromolecular chains. The in vitro blood compatibility of the prepared polymeric materials was determined by methods such as blood clot formation, platelet adhesion, percent hemolysis assay, and protein–adsorption on the surface of the prepared biomaterials.     

Study on Biological Safety of Polyvinyl Alcohol/Collagen Hydrogel as a Tissue Substitute (II)

Physically crosslinked polyvinyl alcohol/collagen composite hydrogels were prepared by a cyclic freezing-drying technique. The biological properties of the hydrogels, including hemolysis, anaphylaxis, pyrogen and acute systemic toxicity tests and implantation in-vivo, were investigated. The hemolysis test suggested that the polyvinyl alcohol/collagen, with a hemolysis index of 1.19%, did not have an obvious hemolysis reaction. There was no toxicosis or death cases observed in the acute systemic toxicity test, and the hydrogel showed no anaphylaxis or pyrogen response. The composite hydrogel showed a good histological compatibility in the in-vivo study. The results indicated that the polyvinyl alcohol/collagen composite hydrogels have promising applications for pharmaceutical and biomedical fields.     

Application of Polyvinyl Alcohol (PVA)/Carboxymethyl Cellulose (CMC) Hydrogel Produced by Conventional Crosslinking or by Freezing and Thawing

Hydrogels for this study were prepared from a mixture of PVA and CMC using three different techniques, i.e., freezing and thawing, electron‐beam irradiation or combined freezing and thawing and electron beam irradiation. A comparative study between the three techniques was carried out in terms of gel fraction (%) and swelling (%). It was found that the physical properties of the hydrogel were improved when the combination of freezing and thawing and irradiation were used rather than just freezing and thawing, or irradiation only. The effects of temperature and soil fertilizers on swelling (%) were examined to evaluate the usefulness of the hydrogel as a super absorbent in the soil. It was found that the swelling ratio increased as the composition of CMC increased in the blend. Hence, the blend having the composition 80/20 (CMC/PVA) was used as a super absorbent in the soil for agriculture. Moreover, the water retention increased in the soil containing this hydrogel. Thus, this type of hydrogel can be used to increase water retention in desert regions.     

Gallic Acid-Loaded Sodium Alginate-Based (Polyvinyl Alcohol-Co-Acrylic Acid) Hydrogel Membranes for Cutaneous Wound Healing: Synthesis and Characterization

Traditional wound dressings often cannot treat wounds caused by bacterial infections or other wound types that are insensitive to these wound treatments. Therefore, a biodegradable, bioactive hydrogel wound dressing could be an effective alternative option. The purpose of this study was to develop a hydrogel membrane comprised of sodium alginate, polyvinyl alcohol, acrylic acid, and gallic acid for treating skin wounds. The newly developed membranes were analyzed using Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and scanning electron microscopy (SEM), X-ray diffraction analysis (XRD), sol-gel fraction, porosity, mechanical strength, swelling, drug release and data modelling, polymeric network parameters, biodegradation, and antioxidation (DPPH and ABTS) and antimicrobial activity against Gram-positive and negative bacteria. The results revealed that hydrogel membranes were crosslinked successfully and had excellent thermal stability, high drug loading, greater mechanical strength, and exhibited excellent biodegradation. Additionally, the swelling ability and the porosity of the surface facilitated a controlled release of the encapsulated drug (gallic acid), with 70.34% release observed at pH 1.2, 70.10% at pH 5.5 (normal skin pH), and 86.24% at pH 7.4 (wounds pH) in 48 h. The gallic acid-loaded hydrogel membranes showed a greater area of inhibition against Pseudomonas aeruginosa, Staphylococcus aureus, and Escherichia coli bacteria as well as demonstrated excellent antioxidant properties. Based on Franz cell analyses, the permeation flux of the drug from optimized formulations through mice skin was 92 (pH 5.5) and 110 (pH 7.4) μg/cm²·h⁻¹. Moreover, hydrogel membranes retained significant amounts of drug in the skin for 24 h, such as 2371 (pH 5.5) and 3300 µg/cm² (pH 7.4). Acute dermal irritation tests in rats showed that hydrogel membranes were nonirritating. Hydrogel membranes containing gallic acid could be an effective option for improving wound healing and could result in faster wound healing.     

Preparation,Characterization and Electromagnetic Shielding Effectiveness of Conductive Polythiophene/Poly(ethylene terephthalate) Composite Fibers

Conductive polythiophene (PTh)/poly(ethylene terephthalate) (PET) composite fibers were prepared by polymerization of thiophene in the presence of PET fibers in acetonitrile medium using FeCl₃. The effects of polymerization conditions such as oxidant/monomer mol ratio and polymerization temperature and time on PTh content and surface electrical resistivity of PTh/PET composite fiber were investigated in detail. It was observed that the usage of preswelled PET fibers in dichloromethane increased the PTh content and decreased surface resistivity of composite fiber. Composite fiber having the highest PTh content (5.7%) and the lowest surface resistivity (80 kΩ) was obtained at 20°C with 1.25 M FeCl₃ and 0.42 M thiophene concentrations. The washing effects of laundering detergent and dry cleaning liquid on surface resistivity of composite fibers were investigated. The electromagnetic shielding effectiveness (EMSE) and relative shielding efficiency by absorption and reflection of composite fibers were measured in the radio and microwave frequency range. The results show that the EMSE values decreased with increasing frequency from radio waves to microwaves with an attenuation of 21 dB to 4 dB.     

二烃基锡双（O，O－二硫代磷酸酯）的合成和波谱研究

合成了１５个二烃基双（Ｏ，Ｏ－二硫代磷酸酯）化合物。利用ＩＲ、（１Ｈ、１３Ｃ、１１９Ｓｎ）ＮＭＲ表征了化合物的结构。这是一类六配位变形八面体结构的二烃基锡化合物。对化合物的质谱裂解机制进行了讨论。     

细菌视紫红质／聚乙烯醇复合膜的制备及相关功能研究

细菌视紫红质（bR)是一种独特的光敏蛋白，具有光致变色和光驱质子泵功能 。将bR蛋白包埋于聚乙烯醇（PVA）基质中，制备了bR/PVA复合膜。利用紫外－可 见分光光度计和自制的毫秒级动力学光谱仪，检测了样品的吸收光谱和光循环M中 间体在脉冲光激发下随时间的变化；同时，利用凝胶扫描成像仪及相关分析软件考 察了样品成膜后的均匀程度。实验表明：bR/PVA复合膜具有良好的均匀性、透明性 和力学性能，而且bR蛋白保持了原有的生物活性和光学性质，bR与M中间体之间能 达到一种光可控制的双稳态，M中间体的寿命也得到了显著的延长，证实了bR可以 提供一个用于信息存储的模型材料。     

Multifaceted polymeric materials in three‐dimensional processing (3DP) technologies: Current progress and prospects

Three‐dimensional printing (3DP) technologies, which are sets of powerful deposition methods employed to fabricate 3D objects with materials in the fields of material sciences and engineering, biomedical and biocompatible structural components, automotive, aviation, and polymers, among others, are currently rapidly developing manufacturing technologies. The methods have significant advantages, which include designing flexibility, enhanced geometrical freedom, low cost, and net shape manufacture, among others, over the traditional “subtractive” method. This review highlights the major 3D printing techniques, especially in the fields of advanced polymeric material fabrication and engineering, as well as the synergy in the incorporation of different types of polymeric materials and composites in a process that will lead to an enhancement of dimensional accuracy for 3D technologies. Furthermore, composite ink systems especially polymer‐based and hydrogel‐based in tissue engineering applications are also discussed.     

聚乙烯醇重氮衍生物-聚甲基丙烯酸高分子复合物固定酶的制备和性质的研究

本文用聚乙烯醇缩对苯甲醛氯化重氮物和聚甲基丙烯酸复合物作为载体,制备了固定化纤维素酶和葡萄糖氧化酶。此固定化酶有较高的活性,贮存、反应稳定性和热稳定性比固定化前都有较大提高。     

Preparation,characterization and compatibility studies of poly(DFAMO/AMMO)

Poly(3-difluoroaminomethyl-3-methyl oxetane (DFAMO)/3-azidomethyl-3-methyl oxetane (AMMO)) (PDA) can be used as an energetic pre-polymer in the binder systems of solid propellants and polymer-bonded explosives (PBXs). The cationic solution polymerization affords PDA using butane diol (BDO) and boron trifluride etherate (TFBE) as initiator and catalyst, separately. Its molecular structure is characterized and thermal decomposition behavior is investigated by thermogravimetric analysis (TG), differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FTIR). The copolymer has good thermal stability and exhibits a three-step mass-loss process with the first two steps mainly belonging to the thermal decomposition of difluoroamino and azido groups, respectively. DSC method is performed to evaluate the compatibility of PDA with some energetic components and inert materials. More than half of the selected materials are compatible with PDA, which including cyclotrimethylenetrinitramine (RDX), 2,4,6-trinitrotoluene (TNT), 1,3,5-triamino-2,4,6-trinitrobenzene (TATB), pentaerythritol tetranitrate (PETN), ammonium perchlorate (AP), ammonium nitrate (AN), potassium nitrate (KNO₃), aluminum powder (Al), aluminum oxide (Al₂O₃), 2-nitrodiphenylamine (NDPA) and 1,3-diethyl-1,3-diphenyl urea (C₁).     

Thermosensitive Microparticles Based on Unsaturated Esters of some Poly- and Oligosaccharides: Preparation,Characterization, Drug Inclusion and Release

Summary: The paper concerns the preparation and characterization of hydrogel microparticles based on exopolysaccharide (Gellan, Xanthan) unsaturated derivatives and respectively on cyclodextrin as well as their application for some hydrosoluble and liposoluble drugs inclusion. In the first step the polysaccharide and cyclodextrin unsaturated esters (maleate, acrylate) were synthesized and their hydrogel forming capacity was tested using a grafting-crosslinking free-radical reaction with N-isopropyl acrylamide (NIPAm), at room temperature. For a better control of the crosslinking degree N,N' methylene-bis-acrylamide (BIS), replaced by cyclodextrin tri-acrylate (A-CD) in a few experiments, was used. The microparticles were obtained by using the method in w/o emulsion, in which the dispersed aqueous phase is the reaction mixture and the oil phase is hexane. The particles containing polysaccharide esters showed an average diameter around 100 µm when crosslinking was achieved with BIS. They were smaller than those crosslinked with A-CD, which are in the range of 200-300 µm; the particles based on Xanthan maleate were smaller than Gellan maleate based ones. Even much smaller particles (2-2.5 µm in diameter) were obtained by starting from A-CD grafted-crosslinked systems. The synthesized microparticles are able to include chloramphenicol, as well as progesterone; the drug is slowly released according to diffusion controlled kinetics. The application of these microparticles in emergency ophthalmic treatments is possible as a result of their thermal sensitivity; they can collapse and release the drug instantly when placed in contact with the human eye, at 37 °C.     

Conductive Composites Based on Metallocene Isotactic Poly(propylene): Preparation and Properties

Summary: The research deals with the preparation and the further comprehensive characterization of metallocene polypropylene-based composite materials by incorporation of carbon black nanoparticles. Composites containing up to 10 wt% of carbon black were prepared by direct melt mixing in a single screw extruder Brabender Extrusiograph type 30/25D with attached static mixer at melt temperature of 200 °C and a screw speed of 30 rpm, according to a two-step process. Some composites were treated with 3 wt% maleic anhydride grafted polypropylene (MAH-PP). The rheological behaviour of the miPP nanocomposites was determined by cone/plate rheological measurements at 180 °C. The composites were characterized by SEM for morphological details and uniaxial stress-strain measurements for determining the mechanical parameters. Electric conductivity of injection molded plates from these composites was investigated. The different miPPs studied are ranked in an ascending order according to their increasing molecular weight concerning the magnitude of their rheological parameters. The maleic anhydride compatibilizer leads to lower viscosity values even at high shear gradients and to better homogenization of the nanofiller in the polymer matrix. The processing conditions, carbon black concentration and viscosity of the virgin polymer have an impact on the final conductivity of the miPP/carbon black composites.     

配位聚合物{[CoL][FeⅡFeⅢ(ox)3·1.5H2O]}∞的合成、波谱表征和磁学性质

A new Schiff base complex， CoL(ClO₄)·3H₂O (1) {L represents condensed from equal molar ratio of sali-cylaldehyde and diethylenetriamine} was synthesized and characterized. Further， a new coordination polymer， {[CoL][Fe^ⅡFe^Ⅲ(ox)₃·1.5H₂O]}_∞ (2)， was synthesized and characterized， where ox^2-=oxalate. The results of the IR and M?ssbauer spectra of 2 revealed that the coordination polymer exists 2-D layer structure in the solid state， and anions layer was formed by [^ⅡFe^Ⅲ(ox)₃]^- unit. The magnetic properties of 2 have been measured and the results indicate that there is magnetic ordering in the low temperature， which may arise from intermolecular ferromagnetic interactions or spin canted effects.     

三(2-甲基-2-苯基丙基)锡羧酸酯的合成、结构表征和生物活性

苯丁锡（Ｔｏｒｇｕｅ［ＰｈＭｅ２ＣＣＨ２）３Ｓｎ］２Ｏ）是高效杀螨剂［１］,国内已实现工业化生产．为了寻找更好的有机锡杀螨剂新品种,人们曾对托尔克进行衍生化,合成了某些三（２－甲基－２－苯基丙基）锡芳氧乙酸酯［２］和某些长链羧酸及取代苯甲酸酯的衍生物［３］．本文拟合成系列新的三（２－甲基－２－苯基丙基）锡羧酸酯,并对目标化合物进行了结构表征和生物活性测定,反应式如下：（ＰｈＭｅ２ＣＣＨ２）３ＳｎＣｌ（１）ＮａＯＨ（２）ＲＣＯＯＨ（ＰｈＭｅ２ＣＣＨ２）３ＳｎＯ２ＣＲＲ＝ＣＨ３（１）,Ｃ２Ｈ５（２）…     

Preparation and Characterization of Poly (D,L-Lactide-co-Glycolide) (PLGA) Nanoparticles Loaded with Linamarin for Controlled Drug Release

Poly (D,L-lactide-co-glycolide) nanoparticles loaded with linamarin as a model drug were successfully prepared using the double emulsion solvent evaporation technique. The physicochemical characterization of the formulated nanoparticles revealed that they were spherical, nonaggregated, and negatively charged, with good drug encapsulation efficiencies (>50%) and average particle sizes <200 nm. Interestingly, all the nanoparticles exhibited dibasic release profiles with a starting burst release within the first 8 h, followed by a controlled release phase lasting four days. Thus, linamarin-loaded nanoparticles indicate a promising candidate for controlled drug release applications.     

Preparation and characterization of novel silk fibroin/2-(N,N-dimethylamino)ethyl methacrylate based composite hydrogels with enhanced mechanical properties for controlled release of cefixime

Hydrogels with improved mechanical properties have been particularly attractive for their applications in the biomedical area including wound healing. For this purpose, a series of novel composite hydrogels based on silk fibroin (SF) and 2-(N,N-dimethylamino) ethyl methacrylate (DMAEMA) were fabricated. The swelling and mechanical tests indicated that an optimum design of hydrogel was essential to provide a high degree of water uptake, higher tensile strength and elongation at break values. Here, the S40D60 was exhibited superior swelling and strong mechanical characteristics than all the other hydrogels with different compositions. Furthermore, it was observed that the cefixime was released from the formulation of S40D60 in a sustainable manner and the drug release rate can be controlled by pH of the dissolution medium. According to these findings, it is suggested that the optimal formulation of S40D60 would be effectively performed in situ drug therapy for wound healing.     

Synthesis and Characterization of Poly （hydroxylethyl, octanediamine）-DL-aspartamide： a New Tissue Engineering Scaffolds

Collagen is the most widely used tissue-derived natural polymer for its goodbiocompatibility and cell adhesion but offers a limited range of mechanical properties1.The construction and properties of synthesized polypeptides are similar to collagen havethe…