高强度水凝胶的制备及其研究进展

水凝胶因其拥有较高的溶胀比和极高的含水率,被广泛应用于各种领域,但力学性能较弱的缺点限制了其在组织工程、软体机器人、可穿戴电子设备等高负载领域的发展。综述了近年来纳米复合水凝胶、双网络水凝胶、大分子微球复合水凝胶、疏水缔合水凝胶等高强度水凝胶的制备方法及研究进展;讨论了各类型高强水凝胶的特点并指出了目前研究中存在的问题;同时,对高强度水凝胶未来的研究方向进行了展望。     

双氯灭痛壳聚糖水凝胶微球的制备及其性能研究

在Span80与植物油形成的反相胶束体系中,通过戊二醛交联制备出壳聚糖水凝胶微球(CHM)。采用红外光谱和透射电镜等方法对CHM结构及粒子形态进行了研究。同时对CHM的溶胀度及其对模型药物双氯灭痛的体外释放行为进行了考察。结果表明,CHM具有较好的控制药物释放的作用。交联程度对微球粒径、溶胀度及药物释放性能影响较大。     

感光溶胶—凝胶法制备光波导薄膜微图案

利用溶胶-凝胶法制备了有机-无机杂化光敏性SiO2-TiO2材料,在单晶硅基片上旋转涂膜,经前烘、紫外光固化、淋洗、后烘等步骤,在硅片上得到复制有掩模微图案的薄膜。用紫外-可见光-近红外分光光度计测试了薄膜的光透过吸收性质,用Fourier红外光谱仪测试了不同紫外光辐照时间下薄膜的红外振动吸收光谱,用高倍光学显微镜和扫描电子显微镜(SEM)观察制备得到的薄膜微图案。结果表明:薄膜在紫外可见光区域的光透过率约为90%,紫外光照能促使不同的官能团间发生缩聚反应,80℃前烘温度处理以及15min左右的紫外光辐照能够得到清晰、精确的薄膜微图案。     

构筑生物分子微图案的研究进展

随着微加工技术的发展,在材料表面构筑功能化的纳微米级图案越来越成为关注的热点。在生物科学领域,光刻蚀、微接触印刷和蘸笔纳米平板印刷等微图案技术被广泛应用并实现了生物分子在几十纳米微区域上的固定。生物分子在微纳米区域内的成功固定大大推动了生物微分析、生物芯片、生物微器件等生物技术及相关领域的发展。本文从分析生物分子与材料表面的相互作用入手,较为系统地评述了构筑生物分子微图案的几种重要方法,并对生物分子微图案技术的发展做了展望。     

基于自组装行为的微球复合水凝胶制备及性能

以超支化的聚乙烯亚胺和烯丙基缩水甘油醚通过环氧开环反应制备了具有温敏性的聚合物,该温敏性聚合物在水溶液中表现出相转变行为,当达到临界温度时能够自组装形成微球.以该微球为交联剂、丙烯酰胺为单体原位在室温下制备出一种微球复合水凝胶(MC H).力学性能测试表明,制备的微球复合水凝胶具有优异的力学性能,断裂伸长率达到2800...     

透明质酸水凝胶的制备与评价

透明质酸(HA)被广泛地用于生物医药领域。以1-乙基-3-(3-二甲基氨丙基)-碳化二亚胺/N-羟基丁二酰亚胺(EDC/NHS)催化HA与己二酸二酰肼(ADH)反应,制备化学交联的HA水凝胶。通过扫描电镜和红外光谱来测定HA与HA水凝胶的结构,测量HA水凝胶在模拟胃肠液中的溶胀率,并以牛血清白蛋白(BSA)为模型药物,初步探讨了HA水凝胶体系的释药行为。实验结果显示:HA水凝胶由酰胺键生成三维网络结构且网络孔径较大,具有较好的吸水性能。该水凝胶制备过程简单,反应迅速,条件温和,属酸敏突释释药体系。     

双网络微球水凝胶对Cu2+的吸附行为研究

工业的迅速发展导致水体环境污染问题也愈加严重,针对重金属废水的处理极为迫切。以海藻酸钠微球为基质,合成出海藻酸钙和聚丙烯酰胺双网络结构的NH₂-SA/PAM微球水凝胶。通过扫描电镜、红外光谱、X射线光电子能谱(XPS)等手段表征可知,该凝胶具有多孔网络结构,具有大量的羟基、氨基等活性位点,能实现离子在凝胶内部的快速扩散。通过对Cu²⁺的吸附实验可知,NH₂-SA/PAM微球水凝胶具有较好的吸附性能,基于Langmuir模型,在30℃下q_max为265.31mg/g,在100min内便达到吸附平衡的80%,通过均相表面扩散模型(HSDM)其凝胶内部的扩散系数D_s为2.83×10^-11m/s。该NH₂-SA/PAM对Pb²⁺、Cd²⁺、Zn²⁺、Mn²⁺、Ni²⁺和Cu²⁺均有较好的吸附性能,其分配系数与离子...     

基于投影光刻技术的微透镜阵列加工方法

本文提出了一种基于投影光刻技术的微透镜阵列制备方法,成功制备多种口径、面形及表面粗糙度均良好的微透镜阵列。该方法采用0.2倍投影物镜,降低掩模板制造成本,实现不同口径微透镜阵列制备。采用掩模移动滤波技术,在降低掩模制备复杂性的同时,提高了微透镜阵列面形精度。本文对四种不同口径的微透镜阵列进行制备实验,分别为50 μm、100 μm、300 μm、500 μm,其表面形貌加工精度达到微米级,表面粗糙度达到纳米级。实验结果表明,该方法在微透镜阵列制造中具有很大的潜力,与传统方法相比,能够实现更低的线宽和更高的表面面形精度。

     

Nanofiber density determines endothelial cell behavior on hydrogel matrix

When cultured under static conditions, bacterial cellulose pellicles, by the nature of the polymer synthesis that involves molecular oxygen, are characterized by two distinct surface sides. The upper surface is denser in fibers (entangled) than the lower surface that shows greater surface porosity. Human umbilical vein endothelial cells (HUVECs) were used to exploit how the microarchitecture (i.e., surface porosity, fiber network structure, surface topology, and fiber density) of bacterial cellulose pellicle surfaces influence cell–biomaterial interaction and therefore cell behavior. Adhesion, cell ingrowth, proliferation, viability and cell death mechanisms were evaluated on the two pellicle surface sides. Cell behavior, including secondary necrosis, is influenced only by the microarchitecture of the surface, since the biomaterial is extremely pure (constituted of cellulose and water only). Cell–cellulose fiber interaction is the determinant signal in the cell–biomaterial responses, isolated from other frequently present interferences such as protein and other chemical traces usually present in cell culture matrices. Our results suggest that microarchitecture of hydrogel materials might determine the performance of biomedical products, such as bacterial cellulose tissue engineering constructs (BCTECs).     

PNIPAAm共聚水凝胶的微波合成和性能

用微波辐射法合成了PNIPAAm共聚水凝胶,表征和测定了孔隙结构、形貌、溶胀和退溶胀速度.结果表明:与水热法相比,用微波辐射法合成的共聚水凝胶孔结构发达;在低于LCST下的溶胀率可达538,远远超过普通水浴法所得的共聚水凝胶的溶胀率;用微波辐射法所合成的PNA系列水凝胶具有比PNIPAAm更高的溶胀和退溶胀速度.微波辐射条件下特殊的"热效应"和"非热效应"有助于合成具有多孔结构网络的共聚水凝胶.这种孔结构有利于水分子的储存和扩散,提高了它的平衡溶胀率和水凝胶对环境温度的响应速度.     

Starch-based adhesive hydrogel with gel-point viscoelastic behavior and its application in wound sealing and hemostasis

Hydrogels with tissue adhesiveness have demonstrated great promise for wearable electronics,artificial skin,soft robotics,and tissue repair.Nevertheless,adhesive hydrogels that are capable of sealing and hemostasis of wound with severe hemorrhage still lack.For this purpose,a series ofionically crosslinked starch hydrogels were developed here.The viscoelastic properties and tissue adhesiveness of the starch hydrogels were investigated.It is shown that the starch and cross linkers had significant influence on the viscoelastic properties of the starch hydrogels,which further resulted in varied tissue adhesiveness.Among the starch gels,there was one exhibiting a unique and stable "Gel Point" viscoelastic characteristic and it was named as gel-point adhesive hydrogel (GPAH).GPAH showed electrical conductivity,high tissue adhesiveness,high stretch-ability,self-healing capability,injectability,and degradability.The GPAH also exhibited high cytocompatibility,low hemolysis risk,and strong antibacterial effect.The wound sealing and hemostatic performance of GPAH was further evaluated by a rat femoral artery injury model.The blood loss after the sealing of GPAH (2.4 ± 1.3 g) was significantly decreased compared to the group using gauze for sealing (6.3 ± 1.5g).Meanwhile,GPAH did not cause pathological changes of the soft tissues surrounding the wound.The above results indicate that GPAH,with high tissue adhesiveness,suitable viscoelastic property,strong antibacterial capacity,as well as electro-conductivity,bears great potential for the applications in smart wound management.     

pH、离子强度敏感性壳聚糖水凝胶的合成及其对辅酶A的控制释放

以壳聚糖(CS),L-天冬氨酸(ASP)和戊二醛(GA)为原料,合成了具有pH、离子强度敏感性的壳聚糖水凝胶CS-GA-ASP.研究了交联剂含量、pH、离子强度对水凝胶溶胀率的影响和水凝胶对辅酶A的控制释放.结果表明,水凝胶在酸性溶液中,溶胀率最大,在中性溶液中溶胀率最小;水凝胶在不同pH或不同离子强度的溶液中交替放置时,表现出良好的溶胀-退胀可逆性;在室温下,pH=3.7、6.8、9的缓冲溶液中,辅酶A的累积释放率分别为78%、92%和87%,且在pH=6.8的缓冲溶液中,辅酶A释放速率最快,在pH=3.7的缓冲溶液中时,辅酶A释放速率最慢.     

半纤维素的提取及其温敏性水凝胶的制备

以采用稀碱抽提法从植物残料中提取的半纤维素为原料,通过化学交联法,自由基聚合将单体接枝到半纤维素链上,并交联温敏性单体,促使形成共聚交联网络结构,得到温度敏感性水凝胶。通过物理交联法,半纤维素与壳聚糖物理交联,制备半纤维素基水凝胶。采用交联度测定、溶胀动力学研究、红外光谱、差示量热等手段对化学交联和物理交联两种方法制得的半纤维素基水凝胶温度响应性能进行表征。结果表明:10%NaOH提取的半纤维素得率最高;化学交联法和物理交联法制得的半纤维素基水凝胶,都具有温度负响应特性,为温敏性水凝胶。作为当下较为热门材料,广泛应用于医疗、农业和生物组织工程材料等领域。     

Incorporation of malonic acid into acrylamide hydrogel by radiation technique and its effect on swelling behavior

Different amounts of malonic acid (MAc) containing acrylamide (AAm) hydrogels were obtained in the form of rods via a radiation technique. Swelling experiments were performed in water at 25°C, gravimetrically. The influence of absorbed dose and malonic acid content of the hydrogels on swelling properties were examined. Diffusion behaviour and network parameters were investigated. Swelling of AAm/MAc hydrogels is increased up to ca. 900%, while pure AAm hydrogels swelled up to ca. 700%. Water diffusion into hydrogels was found to be non-Fickian in character. Diffusion coefficients of AAm/MAc hydrogels were calculated by the short time approximation and found to be 6.4 ×10^–7–10.4 × 10^–7 cm² sec^–1. A possible mechanism for AAm/MAc hydrogels was also suggested.     

Rapid preparation of CuInS2 microparticles via a solution-chemical synthesis route and its characterization

CuInS₂ microparticles were synthesized successfully by a facile solution-chemical method in a mixed solvent of triethylenetetramine–ethylene glycol (1:1, v/v) under the open-air condition using copper chloride, indium chloride and sulfur as starting materials. The factors including the temperature and reaction time which might affect the purity of the product during the synthesis were discussed. Phase constituents, morphology, structure and optical properties of the as-prepared CuInS₂ powders were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), Energy Dispersive Spectrometer (EDS), and ultraviolet–visible (UV–vis) spectrophotometry. It's found that the products were significantly affected by the temperature and reaction time. A possible formation mechanism was put forward and briefly discussed.     

聚乙烯醇/季铵盐壳聚糖复合水凝胶的制备及其烫伤敷料的应用

采用聚乙烯醇为基础材料,以季铵盐壳聚糖为抗菌剂,丙三醇为辅料,采用溶液共混法制备聚乙烯醇/季铵盐壳聚糖复合水凝胶作为皮肤烫伤敷料,通过流变实验、抗菌实验、细胞实验以及动物活体实验考察复合水凝胶的综合性能。结果表明,制备的复合水凝胶具有适宜的粘度(22~35Pa·s),涂覆于皮肤表面呈现较好的粘附性能;对大肠杆菌和金黄色葡萄球菌均有良好的抑菌作用,同时具有优良的细胞相容性;复合水凝胶敷料对皮肤刺激极小,昆明鼠深Ⅱ度烫伤修复实验表明,凝胶敷料可有效加快创面愈合速度以及瘢痕的形成,创面愈合从一般的数周缩减至3周左右,大大缩短创面修复时间,且愈后瘢痕组织小。     

海藻酸钙水凝胶对电刺激的响应行为

以CaCl2为交联剂采用浸渍法制备了海藻酸钙水凝胶,研究了海藻酸钙水凝胶的溶胀吸水率及其电刺激响应行为．结果表明,在NaCl水溶液中,海藻酸钙水凝胶的平衡溶胀比随着NaCl溶液浓度的增大而增大,随着交联剂CaCl2溶液浓度的增大而减小．海藻酸钙水凝胶在NaCl水溶液中在非接触直流电场作用下向负极弯曲,其弯曲速度、弯曲偏转程度和应变随着外加电场强度的增大而增大,随着NaCl溶液离子强度的变化在离子强度I=0．03时出现临界最大值,随着交联剂CaCl2溶液浓度的增大而减小．在周期性电场作用下,海藻酸钙水凝胶的弯曲响应行为具有良好的可逆性．