两性离子水凝胶的制备及生物医学应用

两性离子水凝胶是一类含有两性离子聚合物的凝胶材料,其分子结构中的阴阳离子基团能与水分子紧密结合,形成致密的水合层。这种静电诱导水合作用使得两性离子水凝胶具有极低的生物黏附性,能有效抵抗非特异性蛋白、细胞、细菌等的黏附,具有极低的免疫原性。这些特性使得两性离子水凝胶在生物医用领域有广阔的应用前景。本综述首先介绍了两性离子水凝胶的结构及性质,然后概述了其分类和制备方法,并进一步总结了其在组织工程、药物载体、创伤敷料、生物传感器、医疗器械水凝胶涂层等生物医学领域中的应用。最后展望了两性离子水凝胶未来的发展方向。     

结冷胶与聚乙二醇丙烯酸酯双网络凝胶的制备及生物相容性评价

针对结冷胶脆性较大的问题,将聚乙二醇丙烯酸酯(PEGDA)引入结冷胶,通过紫外交联制备了结冷胶/PEGDA双网络凝胶,并对单组分凝胶和双网络凝胶的溶胀性能、微观形貌、拉伸力学性能、动态压缩性能和流变性能等进行比较.结果表明,双网络凝胶在类生理环境中具有较小的溶胀率和较好的尺寸稳定性,PEGDA的引入能够大幅度提高结冷胶的韧性,双网络凝胶的拉断伸长率可达340%,断裂能达1.01×103J/m2,与天然关节软骨相当.将成纤维细胞种植在凝胶内部进行体外三维立体培养,结果显示,细胞在凝胶内部生存状态良好,双网络凝胶的细胞负载率高于单网络结冷胶,说明该体系在生物医用领域具有良好的应用前景.     

光控水凝胶的构筑及在生物医药领域的应用

水凝胶由于具有优越的保水性、良好的生物相容性和可降解性,被认为是最接近人体组织的生物医用材料。通过构建环境敏感水凝胶可以高度拟合生物组织的微环境,实现其在组织工程与再生医学领域的应用。由于光具有非物理接触和时空分辨等优势,利用光调控技术可实现水凝胶微环境的精确构筑与调控。本文重点介绍了近年来光控水凝胶的构筑,以及在生物医学和材料领域的应用进展。     

甲基丙烯酰胺基明胶水凝胶研究进展

甲基丙烯酰胺基明胶(GelMA)水凝胶的制备及其在生物医学领域的应用是最近十几年的研究热点。GelMA水凝胶因其独特的光致交联特性,可以加工成不同形貌的水凝胶支架材料,同时,因其具有可控的力学性能、降解性能,以及优秀的生物相容性,已成为具有广泛应用前景的生物高分子聚合物材料。本文主要介绍了GelMA水凝胶在止血材料、创伤敷料、组织工程支架、药物控释、骨缺损修复等领域的研究进展。     

PNIPAM温敏微凝胶在生物医学领域中的应用研究

水凝胶因其良好的生物相容性及环境刺激响应性而在生物医学领域有着广泛的用途,但仍存在机械强度差、响应速度慢、不能生物降解等缺点。针对这些问题,特别是宏观水凝胶响应慢的问题,我们近年来以具有温度敏感性的聚N-异丙基丙烯酰胺(PNIPAM)微凝胶为基础,设计制备了一系列生物材料,分别应用于药物控释、生物传感以及组织工程等生物医学领域。我们设计制备了具有良好葡萄糖敏感性的PNIPAM微凝胶,实现了可自我调控的胰岛素可控释放。以PNIPAM微凝胶为基础,提出了新的聚合胶态晶体阵列光学传感方法,设计制备了多种可快速响应的新型生物光学传感器。实现了PNIPAM微凝胶的实时凝胶化,并将其发展成为一种新型的可注射细胞支架材料。进一步利用该体系的可逆性,提出了制备在药物筛选、肿瘤研究以及组织工程等领域有重要用途的多细胞球的新方法。     

水凝胶功能改性研究与应用进展

水凝胶是一种三维网状亲水性高分子软材料,具有良好的固体力学和液体热力学性能,其自身柔软、可塑性强、生物相容性好,具有可降解性和刺激性响应特征。但传统方法制备的水凝胶有诸多缺陷,如有毒性、生物活性低、机械性能差等,使得其应用受限。本文综述了近10年来功能水凝胶制备与改性的主要研究进展及其应用现状,以多吸收位点和高机械强度等性能为主,重点阐述了国内外功能性水凝胶的最新制备方法,包括物理改性中的低分子复合材料交联与构建多重网络和化学改性中的接枝共聚等。详细介绍了该类功能材料在医药、生物、农业和食品等方面的应用现状与发展前景,特别关注了高效短时对外界环境微小变化具有响性的智能印迹水凝胶及其在检测领域的应用,为水凝胶的进一步开发和推广应用提供参考。     

微尺度水凝胶与组织工程

水凝胶已被广泛应用于组织工程、药物控释、生物传感器等生物医学领域。随着微制造技术的发展,在纳微米尺度范围内制备形状和尺寸与自然组织相匹配的工程化水凝胶为解决血管化困难、复杂组织结构模拟、多细胞接种等组织工程难题带来了曙光。本文将主要讨论微尺度水凝胶在组织工程领域的研究现状,重点介绍微尺度水凝胶的合成方法及其在血管化和复杂组织结构模拟方面的应用。     

光聚合水凝胶及其在组织工程中的应用

水凝胶是一种亲水性聚合物网络,可以溶胀大量水,其物理性质接近软组织.光聚合与传统的聚合方法相比,具有反应速率快、反应条件缓和、反应放热低等特点.因此,光聚合水凝胶广泛应用于生物医学领域.本文介绍了光聚合水凝胶材料,并详细论述了光聚合水凝胶在药物释放体系、组织工程支架材料、细胞受控生长、细胞微囊化和可注射水凝胶等方面的应用.可以预见光聚合水凝胶作为生物材料在组织工程及再生医学领域中具有良好的应用前景.     

水凝胶流变学研究概况

水凝胶具有良好的生物相容性和生物可降解性,其结构呈三维网状结构,与细胞外基质相似,在药物释放和组织工程等领域具有广阔的应用前景,被广泛地用于生物制药、生物材料和医学等领域。流变学可以描述材料的流动特性和力学性能,水凝胶的粘弹响应对材料内部结构的变化也非常敏感,因此流变行为被视为研究水凝胶的一种重要方法。本文综述了流变学方法在水凝胶研究中的应用,介绍了水凝胶流变学的研究方法,讨论了影响水凝胶流变学特征的因素,并展望了水凝胶流变学的发展前景。     

聚合物晶胶的制备、性能及生物医学应用

利用低温凝胶化技术制备的聚合物晶胶,具有贯通多孔结构,因其化学/机械稳定性,可用于生物微粒（质粒、病毒、细胞器）和细胞的分离、生物分子和细胞的固定化载体以及组织工程三维支架等领域。本文详细介绍了聚合物晶胶的制备条件（如单体浓度、冷冻过程、引发剂浓度、溶剂等）与其结构、性能的关系;同时,对聚合物晶胶功能化改性及其在生物物质的色谱分离和生物医学领域的应用进行了总结与展望。     

Work Hardening Effects in Gellan Gum Gels1

Abstract

Gellan gum is a bacterial polysaccharide that is marketed as a broad spectrum gelling agent. The shear and Young's moduli, and the fracture strength of gellan gels increase with increasing ionic strength, pass through maxima and then decrease to zero at higher ionic strength. The position of the maxima depend on the valency of added counterions and are virtually independent of polymer concentration. At low ionic strength the measured rheological parameters show small variability but these values become increasingly variable with increasing ionic strength. Stress relaxation experiments were carried out in order to examine the mechanical behaviour of gellan gels and to explain these effects. At low ionic strength the gels approximate to elastic solids whereas at high ionic strength the increased stress relaxation is colloid-like in behaviour. However, unlike colloidal dispersions, the magnitude of the stress relaxation decreases on successive applications of stress and the relaxation modulus increases. The gels work harden. Such behaviour is attributed to a heterogeneous structure within the gel.     

Microwave-Assisted Synthesis and Characterization of Poly(itaconic acid) Grafted Gellan Gum

Poly(itaconic acid) was grafted on GG in aqueous medium under microwave irradiation using a catalytic amount of BPO. Grafted copolymers (GG-g-PIA) were characterized by FT-IR, TGA, and SEM techniques. The influence of microwave power, exposure time, and composition of the reaction mixture on extent of grafting was studied. Conditions for obtaining the highest extent of grafting were optimized. The rate of grafting was determined from weight measurements. The overall activation energy for grafting is found to be to be 28.3 kJ/mol, indicating the possibility of occurrence of the grafting process with absorption of low thermal energy.     

Stability and Rheological Properties of Suspended Pulp Particles Containing Orange Juice Stabilized by Gellan Gum

Gellan was used to suspend pulp particles in orange juice. Three groups of samples were prepared with 0%, 20%, and 40% orange juice concentrate and supplemented with gellan at different concentrations. A concentration-dependent increase in the size of gellan aggregates and gellan-protein assemblies was observed. Incorporation of gellan into the beverage with 0% juice concentrate changed the rheological behavior of sample to non-Newtonian shear-thinning fluid and increased its surface tension. When juice concentrate proportion was increased from 0% to 20%, the beverage viscosity increased. The highest gellan concentration resulted in a higher yield stress (σ₀) value and inhibited the pulp sedimentation completely.      

Grafting of Acrylamide and Trimethylolpropane Triglycidyl Ether onto the Gellan Gum: Synthesis and Characterization

To improve the physiochemical properties of gellan gum(GG), GG was modified with acrylamide and trimethylolpropane triglycidyl ether(TTE). The structure and morphology of modified GG were characterized by Fourier transform infrared(FT-IR) spectroscopy, X-ray diffraction(XRD), differential scanning calorimetry(DSC) and scanning electron microscopy(SEM). The characteristic peaks at 3448, 2788, 1654, 1411, 1117 and 1044 cm~(-1) in the FT-IR spectrum confirm the modification. The XRD and DSC data revealed that the modification enhanced the thermal stability of GG. SEM analysis suggested the modification introduced a porous microstructure, resulting in the adsorption of crystal violet. In addition, the adsorption capacity, thermal stability and swelling property of GGTTE3 were superior to GGTTE1, GGTTE2, GGTTE4 and GGTTE5.     

Antibacterial Broad-Spectrum Dendritic/Gellan Gum Hybrid Hydrogels with Rapid Shape-Forming and Self-Healing for Wound Healing Application

Treating wound infections is a difficult task ever since pathogenic bacteria started to develop resistance to common antibiotics. The present study develops hybrid hydrogels based on the formation of a polyelectrolyte complex between the anionic charges of dopamine-functionalized Gellan Gum (GG-DA) and the cationic moieties of the TMP-G2-alanine dendrimer. The hydrogels thus obtained can be doubly crosslinked with CaCl₂, obtaining solid hydrogels. Or, by oxidizing dopamine to GG-DA, possibly causing further interactions such as Schiff Base and Michael addition to take place, hydrogels called injectables can be obtained. The latter have shear-thinning and self-healing properties (efficiency up to 100%). Human dermal fibroblasts (HDF), human epidermal keratinocytes (HaCaT), and mouse monocyte cells (RAW 264.7), after incubation with hydrogels, in most cases show cell viability up to 100%. Hydrogels exhibit adhesive behavior on various substrates, including porcine skin. At the same time, the dendrimer serves to crosslink the hydrogels and endows them with excellent broad-spectrum microbial eradication activity within four hours, evaluated using Staphylococcus aureus 2569 and Escherichia coli 178. Using the same GG-DA/TMP-G2-alanine ratios hybrid hydrogels with tunable properties and potential for wound dressing applications can be produced.     

瓜尔胶的改性研究

瓜尔胶是水镕性很好的天然高分子之一。本文综述了瓜尔胶的性质，尤其是流变性及化学改性方面的研究进展。     

Microwave-Assisted Synthesis and Characterization of Poly(2-(dimethylamino)ethyl methacrylate) Grafted Gellan Gum

Poly(2-(dimethylamino)ethylmethacrylate) was grafted on gellan gum (GG) in aqueous medium under microwave irradiation using ammonium persulfate and N,N,N′N′-tetramethylethylenediamine as the initiation system. Grafted copolymers were characterized by FT-IR, TGA, and SEM techniques. The influence of microwave power, exposure time, and composition of the reaction mixture on extent of grafting was studied. Conditions for obtaining the highest degree of grafting were optimized. The rate of grafting was determined from weight measurements. The overall activation energy for grafting is found to be 31.2 kJ/mol, indicating the occurrence of the grafting process with absorption of low thermal energy.     

季铵型阳离子田菁胶的制备及絮凝作用

季铵型阳离子田菁胶的制备及絮凝作用;化学改性;混凝     

生物高分子黄原胶的性能、应用与功能化

讨论了黄原胶生物大分子的结构与性能关系，从有关黄原胶的性能、开发应用以及在抗菌素药物负载与控择、分散稳定与防腐作用，及其与有机硅化合物配伍制备消泡表面活性材料等，进行功能化改性方面，综述了近20年来国内外研究状况，并探讨了开展生物高分子黄原胶应用与开发研究的思路。     

Synthesis of Hydroxypropyl Guar Gum by Phase Transfer Catalysis

HGG (Hydroxypropyl guar gum) was synthesized by phase transfer catalysis for the first time. The effects of alkalinity, phase transfer catalyst, etherification, pH value, temperature,reaction time and stirring speed were investigated. An optimal synthetic reaction technology was established, namely, dose of guar gum is 100 g, propylene oxide 40-50 g, HTAC (hexadecyl trimethyl ammonium chloride ) 1.3-1.7 g, pH value 10-10.5, temperature 45-50~C, and reaction time 3-4 hours. The result shows that the improved HGG has high viscosity. Its dissolution speed, content of insoluble residue, colloid light transparency and stability are apparently superior to guar flour.