智能型水凝胶结构及响应机理的研究进展

综述了智能型水凝胶研究的新进展,简要介绍了几类新型的刺激响应性水凝胶,分析了影响水凝胶敏感性的结构因素,介绍了水凝胶的有关理论,动力学研究和敏感性机理。     

原子转移自由基聚合在智能型水凝胶制备中的应用

分别对原子转移自由基聚合和智能型水凝胶两者进行了综述,分析总结了利用原子转移自由基聚合制备智能型水凝胶方面的应用情况,并对其前景作了一定的展望.     

智能水凝胶双抗癌药物控释体系

近年来,基于联合用药策略的双药物控释体系的研究为降低抗癌药物毒性和提高疗效提供了有效途径。水凝胶作为一类高临床应用价值的药物载体,在药物控释方面具有广泛的应用前景。癌症是危害人类健康和生命的疾病之一,当人体内正常细胞发生癌变后,癌变细胞周围会发生一些显著的变化。因此,根据肿瘤细胞与正常细胞在体内环境及体外环境的差异,发展了多种智能型水凝胶双抗癌药物控释载体。它能够在感知外界因素的刺激下发生内部结构的变化,从而实现对药物的可控释放。与此同时,随着新的治疗手段的兴起和更多抗癌作用靶点的发现,水凝胶载体也成功实现了化学药物和生物治疗因子的同时负载和可控释放。本文将从不同智能型水凝胶载体如何负载、控释双抗癌药物及水凝胶药物载体中药物的组合方式两方面综述智能型水凝胶双抗癌药物控释体系最新研究进展,并展望其发展前景。     

一种新型的可生物降解的热敏凝胶微粒的制备

聚合物水凝胶是由高分子组成的三维空间交联网络与水的混合体系,有望在药物控制释放等领域获得广泛应用,某些水凝胶还具有显著的环境响应性,构成了一类主流的智能材料,在生物医用材料领域,对于材料的可降解性有严格要求,而单一的可降解药物缓释载体材料和单一的智能型水凝胶材料已有较多报道,但能够将这两种特性结合在同一种材料中的报道则很少,其中智能响应范围合适、降解速率易于大范围调节的合成水凝胶则更少。     

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。     

智能性水凝胶

“智能”材料具有传感、处理和执行功能，水凝胶作为智能材料其应用前景良好。本文综述了智能水凝胶的近期研究发展，以Ｆｌｏｒｙ的溶胀理论着重探讨了刺激响应性，并介绍了化学机械现象及凝胶相转变。     

电场驱动的高分子凝胶

本文较系统地阐述了电场驱动的高分子水凝胶、有机凝胶的响应机理，并扼要介绍了此类凝胶应用的最新进展。     

石墨烯基水凝胶的研究进展

石墨烯具有独特的导电、导热和力学性能,既能够自组装为电化学性能优良的石墨烯水凝胶,又可以与小分子和聚合物进行复合制备多功能性复合水凝胶,大幅度地拓展了传统水凝胶的应用范围。本文主要分为四部分来综述近些年来石墨烯基水凝胶的研究进展。第一部分简要介绍了石墨烯的研究背景和石墨烯基水凝胶的研究意义。第二部分主要根据石墨烯基水凝胶的组成将其分为石墨烯水凝胶、石墨烯/小分子和石墨烯/聚合物复合水凝胶三类,分别介绍了它们的制备方法、形成机理和凝胶性能。其中,对石墨烯/小分子复合水凝胶的介绍以石墨烯基超分子水凝胶为主,而对石墨烯/聚合物复合水凝胶的介绍以智能型水凝胶为主。第三部分主要介绍了石墨烯基水凝胶在超级电容器、水处理、控释药物、微流体开关、催化剂载体等方面的应用和发展。最后,对该领域所面临的挑战进行了总结和展望。     

DNA水凝胶在生物传感中的应用和发展

脱氧核糖核酸(DNA)是一种重要的生物分子,具有许多独特的性质如:信息传递、分子识别、可编辑等。DNA水凝胶同时具有DNA分子和水凝胶材料的优势,并且可以引入其他纳米材料获得多功能杂化水凝胶。相比于传统水凝胶,DNA水凝胶具有良好的特异识别能力以及可以按需设计的性质,从而被广泛应用于生物传感领域。本文围绕DNA水凝胶的合成、响应机制以及在传感领域的应用进行综述。按照不同的合成方法可分为线性DNA链缠绕水凝胶、枝状DNA自组装水凝胶、杂合DNA水凝胶。根据传感机制的不同又可以分为包埋封装法和非包埋封装法,包埋封装发法又分为:酶的包埋释放、抗原-抗体的包埋释放、纳米材料的包埋释放。本文总结了近几年DNA水凝胶在重金属离子检测、核酸检测、葡萄糖检测、蛋白质和代谢小分子检测,以及细胞检测等热门领域的研究情况,最后对其未来的发展进行了展望。     

水凝胶及其在药物控释体系上的应用

智能水凝胶作为药物载体有着良好的应用前景。人体环境中存在一些变化的因素，如温度、pH。因此，温度敏感性水凝胶和pH敏感性水凝胶可用于药物在人体中的控释体系。本文主要介绍水凝胶材料的种类以及智能水凝胶在药物控释体系上的应用。     

Injectable baicalin/F127 hydrogel with antioxidant activity for enhanced wound healing

Baicalin, extracted from traditional Chinese medicine Scutellaria baicalensis Georg, possesses multiple pharmacological activities and has great potential for chronic skin wound repair. However, the poor solubility and lack of suitable vehicles greatly limit its further application. Herein, we proposed a convenient and robust strategy, employing PBS solution as solvent, to enhance the solubility of baicalin. Furthermore, we constructed injectable baicalin/F127 hydrogels to study their application in skin wound treatment. The composition and temperature sensitivity of baicalin/Pluronic® F-127 hydrogels were confirmed by FTIR and rheological testing, respectively. In vitro release measurement indicated that the first order model was best fitted with the release profile of baicalin from hydrogel matrix. Besides, MTT assay, AO/EO staining assay as well as hemolytic activity test revealed the excellent cytocompatibility of baicalin/F127 hydrogels. Antioxidant activity assay demonstrated the cytoprotective activity of baicalin/F127 hydrogels against reactive oxygen species (ROS). Furthermore, the in vivo experiments exhibited the ability of baicalin/F127 hydrogel to accelerate wound healing. In conclusion, this novel injectable baicalin/F127 hydrogel should have bright application for chronic wound treatment.     

Selection of hydrogel electrolytes for flexible zinc–air batteries

Flexible zinc–air batteries attract more attention due to their high energy density, safety, environmental protection, and low cost. However, the traditional aqueous electrolyte has the disadvantages of leakage and water evaporation, which cannot meet application demand of flexible zinc–air batteries. Hydrogels possessing good conductivity and mechanical properties become a candidate as the electrolytes of flexible zinc–air batteries. In this work, advances in aspects of conductivity, mechanical toughness, environmental adaptability, and interfacial compatibility of hydrogel electrolytes for flexible zinc–air batteries are investigated. First, the additives to improve conductivity of hydrogel electrolytes are summarized. Second, the measures to enhance the mechanical properties of hydrogels are taken by way of structure optimization and composition modification. Third, the environmental adaptability of hydrogel electrolytes is listed in terms of temperature, humidity, and air composition. Fourth, the compatibility of electrolyte–electrode interface is discussed from physical properties of hydrogels. Finally, the prospect for development and application of hydrogels is put forward.     

Hofmeister效应辅助的蛋白质基水凝胶应变传感器

以酪蛋白酸钠和明胶为原料, 通过简单的在硫酸铵溶液中浸泡的方法, 借助Hofmeister效应制备了一种强韧导电的酪蛋白酸钠/明胶水凝胶, 克服了蛋白质基水凝胶柔软、 易碎的问题. 测试结果表明, 该水凝胶具有优异的机械性能, 最大拉伸应力为3.55 MPa, 最大拉伸应变为1375%; 水凝胶的最大电导率为0.0954 S/cm, 导电灵敏因子为0.53. 用该水凝胶制备的传感器对不同大小及不同速率的应变均具有分辨能力, 能够监测人体不同部位的运动, 且传感器的信号传输具有稳定性和准确性, 表明该水凝胶是监测人体健康和运动的理想材料. 该水凝胶还具有良好的形状记忆性能. 这一策略为制备全天然蛋白质基水凝胶开辟了新的思路, 扩展了水凝胶在生物医学和电子传感等相关领域的应用前景.     

Amorphous Silk Fibroin Nanofiber Hydrogels with Enhanced Mechanical Properties

Silk fibroin (SF) hydrogels have been engineered as universal substrates for various tissue regenerations and drug delivery. Although different physical and chemical crosslinking strategies are developed to form SF hydrogels with suitable performances, a significant gap remains to match specific requirements of various tissues. Here, amorphous SF nanofibers with more tyrosine residues outside the surfaces are used to replace traditional SF. Under the same crosslinking conditions, the use of amorphous SF nanofibers results in tougher properties, four times higher stiffness than that from traditional SF solutions. Unlike previous SF hydrogels, the SF nanofiber hydrogels show high tunability in wide modulus range of 0.6–160 kPa under low SF concentrations (below 5 wt%), showing improved mechanical match with various soft tissues. Better stability and cytocompatibility are also achieved, further confirming the superiority of the hydrogels as the tissue substrates. Therefore, a feasible strategy is developed to optimize the performances of SF hydrogel via tuning the nano‐structural state in aqueous solutions, which will enrich SF‐based hydrogel family in future.     

Bioresponsive DNA-co-polymer hydrogels for fabrication of sensors

Bioresponsive hydrogels that include DNA within a non-DNA network (DNA-co-polymer hydrogels) constitute a group of soft materials possessing selective recognition ability hosted by the included DNA structure. They are furthermore characterized by the changes to the hydrogel properties which follow the recognition of the biological analyte. Such hydrogels can be synthesized with desired recognition ability through the selection of particular nucleotide sequence that is recognizing or binding ions, small molecules, biomolecules or parts of larger entities. The binding of the label-free analyte triggers a response of the hydrogel, such as changes in its swelling volume, mass, optical or mechanical properties. The hydrogel response is mediated by changes in network parameters such as charge density, crosslinking density or a combination of these associated with the interaction with the analyte. Bioresponsive DNA polymer hydrogels have found wide application in biosensors due to their versatile nature.     

Computational approaches for understanding and predicting the self-assembled peptide hydrogels

Self-assembled peptide hydrogel is a promising biomaterial and has been widely applied in many fields. As a typical self-assembly material, peptide hydrogel exhibits properties different from traditional polymer hydrogel, and has unique features in molecular design, structural elements of hydrogel, and control strategies. With the desire to apply the principles of self-assembly to the design and prediction of peptide hydrogels, there has more and more emphasis on understanding the driving forces and microscopic behaviors involved in the self-assembly process. Computational methods have played an increasingly important role in recent research in helping to reveal the relationship between molecular chemical structure and self-assembly processes as well as assembled morphologies, thus determining the ability of supramolecular gelation. This review aims to summarize the application of computational tools to obtain a better fundamental understanding of the multi-scale structural details of self-assembled peptide hydrogels and to predict the gelation behavior of supramolecular nanofibers. It is expected that researchers will consider using these computational tools when investigating and designing novel peptide hydrogel materials.     

Evaluation of the degree of cross-linking of cellulose-based superabsorbent hydrogels: a comparison between different techniques

Three different techniques have been applied to the evaluation of the degree of cross-linking of superabsorbent cellulose-based hydrogels obtained from water solutions of carboxymethylcellulose sodium salt (CMCNa) and hydroxyethylcellulose (HEC), chemically cross-linked with divinyl sulfone. These polyelectrolyte hydrogels are biodegradable and have the same sorption capacity as acrylate-based superabsorbents on the market. A ¹³C solid state NMR analysis was carried out on dry samples of hydrogel to obtain the degree of cross-linking, an important parameter that affects the swelling and mechanical properties of a hydrogel. Dynamic mechanical analysis was performed during the hydrogel cross-linking using a parallel plate rheometer under oscillatory deformations in order to monitor the evolution of the hydrogel viscoelastic properties during the synthesis. The value of |G*| and the slope of the stress-deformation ratio plots from uniaxial compression tests were used to evaluate the elastically effective degree of cross-linking according to classical rubber elasticity theory. Moreover, a dynamic mechanical analysis was carried out on cross-linked hydrogels at different degrees of swelling in order to investigate the influence of the swelling on the mechanical properties and the application of rubber elasticity theory to swollen hydrogels.     

溶致液晶作模板水凝胶的制备及其表征

以表面活性剂Brij 58溶致液晶(LLC)为模板, 采用光聚合的方法合成了结构规整的新型溶致液晶型聚丙烯酰胺(PAAm)水凝胶, 并对其结构、形貌和性能进行了研究. 扫描电镜结果表明活性剂Brij 58用量为10%～40%时, 可形成结构规整、孔径均一的LLC型水凝胶, 其孔径为1～2 µm, 约为普通水凝胶的1/40. 当Brij 58浓度大于50%时, 体系发生相分离, 此时合成的水凝胶含水量及孔隙率下降. 傅立叶变换红外光谱(FTIR)显示, LLC型水凝胶中羰基和氨基的红外吸收向低波数方向移动, 表明其中形成了大量的分子间氢键. 同时, LLC型PAAm水凝胶还保持了普通水凝胶的pH敏感性, 相同条件下, 其溶胀比大于普通水凝胶.     

Peptide dendrimer-crosslinked inorganic-organic hybrid supramolecular hydrogel for efficient anti-biofouling

A novel kind of inorganic-organic hybrid supramolecular hydrogel with excellent anti-biofouling capability was developed. The hydrogel was formed via ionic interaction between the negative-charged sodium polyacrylate (SPA) entwined clay nanosheets (CNS) and positive-charged polyhedral oligomeric silsesquioxane (POSS) core-based generation one (L-Arginine) dendrimer (POSS-R).     

电场敏感的智能性水凝胶*

电场敏感水凝胶是一类在电刺激下可以溶胀、收缩或弯曲的智能性水凝胶,其主要特点是可以将电能转化为机械能。本文对近年来已见报道的电场敏感水凝胶的研究进行了较为详细的综述。同时,对电场敏感水凝胶的响应机理、影响水凝胶响应性的因素以及其在能量转换装置、人工肌肉等方面的应用也作了相应的介绍。