环境刺激响应型高强度智能水凝胶研究进展

环境刺激响应型智能水凝胶能够对外界环境因素的变化产生显著的体积或其他特性的变化,且其性质和结构与生物组织类似,有望应用于人工软骨、人造肌肉、组织工程等领域,引起了广泛的关注。提高环境刺激响应型智能水凝胶的力学性能是智能水凝胶应用研究的重要方向之一。本文综述了近年来环境刺激响应型高强度智能水凝胶的研究进展,简述了高强度智能水凝胶的网络结构的构建策略与方法,分析了其具备高力学性能的机理,重点介绍了4类不同结构的高强度智能水凝胶,即超低交联结构水凝胶、纳米颗粒复合水凝胶、拓扑结构水凝胶以及双网络结构水凝胶,最后讨论了环境刺激响应型高强度智能水凝胶在面向应用的研究过程中仍然需要解决的关键科学问题,如智能水凝胶的环境刺激与力学性能的博弈效应以及响应环境刺激前后的力学性能差异等。     

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正环境刺激响应型高强智能水凝胶研发引人瞩目环境刺激响应型智能水凝胶能够对外界环境因素的变化产生显著的体积或其他特性的变化,且其性质和结构与生物组织类似,有望应用于传感器、人工肌肉、软体机器人、组织工程、化学反应开关或微阀、物质分离、药物控释等许多领域,具有很重要的意义和经济价值,其研发引人注目。近年来研发的主要有四类不同结构的环境刺激响应型高强智能水凝胶:超低交联结构水凝胶、纳米颗粒复合水凝胶、双网     

刺激响应性水凝胶的研究现状及发展趋势

刺激响应性水凝胶在药物缓释、物质分离提纯等领域得到了广泛的应用,文章介绍了能响应温度、pH、光、电场和磁场等外界环境因素变化智能凝胶的结构特点和近期研究进展,并展望了智能凝胶的应用前景。     

环境响应型Pickering乳液的研究进展

环境响应型智能水凝胶能够对外界环境温度、pH值、CO2气体、磁场等变化产生显著的体积或其他特性的变化,且其性质和结构与生物组织类似,有望应用于药物运输、细胞封装、组织工程等领域,引起了广泛的关注.近年来,采用环境响应型粒子作为Pickering乳液的乳化剂,制备出一种新型高效的乳剂成为研究热点.介绍了环境响应型粒子稳定乳液的研究进展,最后提出了未来食品和药物运输等领域环境响应型Pickering乳液的研究趋势.     

智能水凝胶的研究进展

智能水凝胶是指在外界环境(如温度、pH值、电场等)发生变化时,性质随之发生相应改变的水凝胶,即具有环境响应性。水凝胶尤其是智能水凝胶由于其迷人的性质及潜在的应用引起广大科技工作者的研究兴趣。根据智能水凝胶对环境的响应情况,作者详细介绍了pH敏感性水凝胶、温度敏感性水凝胶、光敏感性水凝胶、电场敏感性水凝胶、磁敏感性水凝胶、盐敏感性水凝胶、化学物质敏感性水凝胶以及多重敏感性水凝胶的研究情况,同时对智能水凝胶的研究方向和应用前景进行了展望。     

响应性光子晶体的研究进展

简要介绍了光子晶体的概念及各种制备方法,详细综述了响应性光子晶体的研究进展,包括:1胶体晶体水凝胶阵列;2反蛋白石结构水凝胶;3反蛋白石状光子晶体微球;4微凝胶胶体晶体;5浸润性控制的光子晶体。     

智能水凝胶在生物载药领域的研究进展

智能水凝胶是一类具有三维网络结构、膨胀性好、吸水性强、易保水、超仿生等特点的新型功能高分子材料。由于其合成过程中加入了具有特殊结构、基团的单体或者大分子原料,如聚丙烯酰胺(PNIPA)类大分子、酸/碱基团(如羧基和氨基)、丙烯酸、聚氨类、偶氮苯(As)、聚电解质(高分子链上有可以离子化的基团)等,因此智能水凝胶是能够根据环境的温度、酸度、电场、磁场等变化做出有规律的结构和体积调整,或者导致凝胶组成发生变化的新型智能生物化学水凝胶材料,具有较高的智能性和响应性。本文根据水凝胶对外界环境的刺激不同表现出不同的响应情况,将凝胶分为:温度敏感性水凝胶、pH敏感性水凝胶、光敏感性水凝胶、压力敏感性水凝胶、电场敏感性水凝胶等。近年来,随着人们对医用水凝胶和药物缓释研究的深入,具有环境敏感性和较好生物相容性的智能水凝胶成为临床上药物控释材料的首选。     

快速响应的温敏性PNIPAAm／粘土复合水凝胶的合成及性能研究

以碳酸钠为制孔剂合成了快速响应的温敏性PNIPAAm／粘土复合水凝胶(NNC水凝胶),DSC分析表明,其体积相转变温度在33℃左右,与传统的PNIPAAm水凝胶没有很大的偏差。动力学研究表明,该水凝胶在温敏膨胀或收缩时,具有快速的响应速率,在5 min内的失水率达90％以上,这与扫描电镜观察到水凝胶具有大而连贯的孔洞结构相一致。     

双多重刺激响应水凝胶应用于伤口愈合的研究进展

介绍了伤口愈合的过程以及愈合过程中伤口处微环境的变化,叙述了目前根据伤口处不同环境变化(如pH、温度、活性氧含量和葡萄糖含量等)而设计的智能响应水凝胶,总结了可以应对2种及以上伤口微环境变化的双重或多重刺激响应性水凝胶的制备过程,以及水凝胶如何对伤口实现智能响应和精准治疗的应用,并讨论了今后应用于伤口愈合水凝胶的设计方向。认为目前的水凝胶多数用于浅表创伤的治疗,如何对深度损伤的慢性伤口实现加速愈合的效果是扩展水凝胶应用的关键;从材料角度出发,可以深度研究创面愈合机制,设计开发多重刺激响应水凝胶以满足不同类型的创面的需求,从而使水凝胶在伤口愈合方面有更广阔的应用前景。     

快速响应葡萄糖敏感微凝胶的制备及性能

以3-氨基苯硼酸(AAPBA),N,N'-二甲基丙烯酰胺(DMAA),丙烯酰胺(AAm)为单体,N,N-亚甲基双丙烯酰胺(MBA)为交联剂,十二烷基硫酸钠(SDS)为表面活性剂,过硫酸钾(KPS)为引发剂,70℃下经乳液聚合制备了P(AAPBA-DMAA-co-AAm)微凝胶。采用FTIR,SEM和TG对微凝胶的化学结构、表面形貌和热稳定性进行了表征,粒径测试得出微凝胶的粒径分布均匀、分散性良好。通过称量法和吸光度法对微凝胶的葡萄糖响应性进行了测试。模拟人体环境进行响应实验,表明微凝胶的响应速率随着葡萄糖浓度的增加而增大,约10 min达到平衡,且具有良好的响应重现性。微凝胶对葡萄糖的快速响应为微凝胶用于药物释放体系奠定了基础。     

基于智能高分子材料的灵敏检测技术研究进展

近年来,将智能高分子材料识别响应的微小刺激信号转化并放大为方便人们读取的信号检测技术成为研究热点。本工作综述了近年来基于智能高分子材料的灵敏检测技术的研究进展,重点介绍了将智能高分子材料识别响应刺激信号转化为电信号、流量信号和光信号的检测技术。最后讨论了基于智能高分子材料的灵敏检测技术应用时需解决的关键问题,为基于智能高分子材料的灵敏检测技术的设计与应用提供了有价值的参考。     

Smart carboxymethylchitosan hydrogels that have thermo‐ and pH‐responsive properties

Thermo‐responsive poly(N‐isopropylacrylamide) (poly(NIPAAm)) and pH‐responsive poly(N,N′‐diethylaminoethyl methacrylate) (poly(DEAEMA)) polymers were grafted to carboxymethylchitosan (CMC) via radical polymerization to form highly water swellable hydrogels with dual responsive properties. Ratios of CMC, NIPAAm to DEAEMA used in the reactions were finely adjusted such that the thermo and pH responsiveness of the hydrogels was retained. Scanning electron microscopy (SEM) indicated the formation of an internal porous structure for the swollen CMC hydrogels upon incorporation of poly(NIPAAm) and poly(DEAEMA). Effect of temperature and pH changes on water swelling properties of the hydrogels was investigated. It was found that the water swelling of the hydrogels was enhanced when the solution pH was under basic conditions (pH 11) or the temperature was below its lower critical solution temperature (LCST). These responsive properties can be used to regulate releasing rate of an entrapped drug from the hydrogels, a model drug, indomethacin was used to demonstrate the release. These smart and nontoxic CMC‐based hydrogels show great potential for use in controlled drug release applications with controllable on‐off switch properties. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41505.     

Synthesis of multifunctional high strength,highly swellable,stretchable and self‐healable pH‐responsive ionic double network hydrogels

The multifunctional double network (DN) soft hydrogels reported here are highly swellable and stretchable pH‐responsive smart hydrogel materials with sufficient strength and self‐healing properties. Such multifunctional hydrogels are achieved using double crosslinking structures with multiple physical and chemical crosslinks. They consist of a copolymer network of acrylamide (AM) and sodium acrylate (Na‐AA) and other reversible network of poly(vinyl alcohol)–borax complex. They were characterized by Fourier transform IR analysis and studied for their hydrogen bonding and ionic interaction. The degree of equilibrium swelling was observed to be as high as 5959% (at pH 7.0) for a hydrogel with AM/Na‐AA = 25/75 wt% in the network (GS‐6 sample). The highest degree of swelling was observed to be 6494% at pH 8.5. The maximum tensile strength was measured to be 1670, 580 and 130 kPa for a DN hydrogel (GS‐2 sample: AM/Na‐AA =75/25 wt% with 20, 40 and 60 wt% water content, respectively). The self‐healing efficiency was estimated to be 69% for such a hydrogel. These multifunctional DN hydrogels with amalgamation of many functional properties are unique in hydrogel materials and such materials may find applications in sensors, actuators, smart windows and biomedical applications. © 2018 Society of Chemical Industry     

Molecular design,synthesis strategies and recent advances of hydrogels for wound dressing applications

With the changes in the modern disease spectrum, pressure ulcers, diabetic feet, and vascular-derived diseases caused refractory wounds is increasing rapidly. The development of wound dressings has partly improved the effect of wound management. However, traditional wound dressings can only cover the wound and block bacteria, but are generally powerless to recurrent wound infection and tissue healing. There is an urgent need to develop a new type of wound dressing with comprehensive performance to achieve multiple effects such as protecting the wound site from the external environment, absorbing wound exudate, anti-inflammatory, antibacterial, and accelerating wound healing process. Hydrogel wound dressings have the aforementioned characteristics, and can keep the wound in a moist environment because of the high water content, which is an ideal choice for wound treatment. This review introduces the wound healing process and the development and performance advantages of hydrogel wound dressings. The choice of different preparation materials gives the particularities of different hydrogel wound dressings. It also systematically explains the main physical and chemical crosslinking methods for hydrogel synthesis. Besides, in-depth discussion of four typical hydrogel wound dressings including double network hydrogels, nanocomposite hydrogels, drug-loaded hydrogels and smart hydrogels fully demonstrates the feasibility of developing hydrogels as wound dressing products and their future development trends.     

影响电刺激响应型智能水凝胶弯曲行为的因素

电刺激响应型水凝胶是一类在电场作用下可以发生溶胀、收缩、变形、弯曲等行为的智能型凝胶,其中弯曲行为具有良好的应用前景。本文主要对智能型水凝胶发生弯曲行为的机理、影响因素以及在药物输送系统中的应用进行了综述并进行展望。     

Advances in the Structural Strategies of the Self-Assembly of Photoresponsive Supramolecular Systems

Photosensitive supramolecular systems have garnered attention due to their potential to catalyze highly specific tasks through structural changes triggered by a light stimulus. The tunability of their chemical structure and charge transfer properties provides opportunities for designing and developing smart materials for multidisciplinary applications. This review focuses on the approaches reported in the literature for tailoring properties of the photosensitive supramolecular systems, including MOFs, MOPs, and HOFs. We discuss relevant aspects regarding their chemical structure, action mechanisms, design principles, applications, and future perspectives.     

Synthesis,characterization and,swelling behavior of semi‐IPN nanocomposite hydrogels of alginate with poly(N‐isopropylacrylamide) crosslinked by nanoclay

pH and temperature responsive nanocomposite hydrogels were synthesized with sodium alginate (NaAlg), N‐isopropylacrylamide (NIPA), and nanoclay. The structure, morphology, thermal behavior, and swelling and deswelling behaviors of the hydrogels were studied. The NaAlgm/PNIPA/Clayn hydrogels revealed a highly porous structure in which the pore sizes decreased and the amount of pores increased with increasing the nanoclay content in the hydrogels. PNIPA retained its own characteristics regardless of the amount of NaAlg and nanoclay. The effect of pH and nanoclay content on the swelling and effect of temperature on the deswelling behavior were investigated. The equilibrium swelling ratios of the nanocomposite hydrogels increased with increasing the pH from 2 to 6. The maximum swelling was attained at pH 6. Deswelling increased with increasing the nanoclay content in the hydrogels. The hydrogels were found to be pH and temperature responsive. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43222.     

A responsive supramolecular hydrogel with robust mechanical properties for actuator and strain sensor

Responsive hydrogels hold great promise for applications such as biological tissue engineering, controlled drug release, soft actuators, and intelligent sensors. However, the design and construction of robust responsive hydrogels using a simple method remains a significant challenge. Herein, a non-covalently crosslinked responsive hydrogel was constructed by introducing carboxyl-Zr⁴⁺ metal coordination to the hydrophobic association network of P(AA-co-LMA) hydrogel through a facile one-pot polymerization method. The incorporation of multiple reversible interactions, including hydrogen bonding, metal coordination, and hydrophobic association, resulted in a responsive hydrogel with exceptional mechanical strength (≈2.92 MPa), outstanding flexibility (elongation>1000%), and rapid response to pH alterations. Furthermore, the hydrogel also presented good ionic conductivity due to the abundant movable ions, as well as high sensitivity and stability. As application demonstrations, the supermolecular hydrogel had been successfully used in actuating and strain sensing. This work establishes an effective design strategy for creating tough and multifunctional responsive hydrogel.     

NVCL-Based Hydrogels and Composites for Biomedical Applications: Progress in the Last Ten Years

Hydrogels consist of three-dimensionally crosslinked polymeric chains, are hydrophilic, have the ability to absorb other molecules in their structure and are relatively easy to obtain. However, in order to improve some of their properties, usually mechanical, or to provide them with some physical, chemical or biological characteristics, hydrogels have been synthesized combined with other synthetic or natural polymers, filled with inorganic nanoparticles, metals, and even polymeric nanoparticles, giving rise to composite hydrogels. In general, different types of hydrogels have been synthesized; however, in this review, we refer to those obtained from the thermosensitive polymer poly(N-vinylcaprolactam) (PNVCL) and we focus on the definition, properties, synthesis techniques, nanomaterials used as fillers in composites and mainly applications of PNVCL-based hydrogels in the biomedical area. This type of material has great potential in biomedical applications such as drug delivery systems, tissue engineering, as antimicrobials and in diagnostic and bioimaging.