11-苄硒基十一羧酸铵盐的双重刺激响应性质

合成了一种对氧化还原(Redox)和CO_2/N_2具有双重刺激响应的表面活性剂11-苄硒基十一羧酸铵盐(BSeUA),分别利用傅里叶红外光谱、核磁共振和电喷雾质谱等手段研究了BSeUA在Redox和CO_2/N_2刺激响应前后的分子结构变化特征。结果表明,在过氧化氢和水合肼交替作用下,BSeUA分子中二价硒醚基团(-Se-)与相应的四价硒亚砜基团(-Se=O)之间可以氧化还原可逆互变,在CO_2和N_2交替作用下,BSeUA分子中羧酸根(-COO-)与相应的羧酸(-COOH)之间可以可逆互变,从而实现BSeUA对Redox和CO_2/N_2具有双重刺激响应。分别在Redox和CO_2/N_2刺激作用下,由BSeUA稳定的乳液可以在破乳和再乳化2种状态下开关可逆循环至少5次,且乳液粒径和稳定性未发生明显变化。     

Stimuli-Responsive Nanocomposite Hydrogels for Biomedical Applications

The complex tissue-specific physiology that is orchestrated from the nano- to the macroscale, in conjugation with the dynamic biophysical/biochemical stimuli underlying biological processes, has inspired the design of sophisticated hydrogels and nanoparticle systems exhibiting stimuli-responsive features. Recently, hydrogels and nanoparticles have been combined in advanced nanocomposite hybrid platforms expanding their range of biomedical applications. The ease and flexibility of attaining modular nanocomposite hydrogel constructs by selecting different classes of nanomaterials/hydrogels, or tuning nanoparticle-hydrogel physicochemical interactions widely expands the range of attainable properties to levels beyond those of traditional platforms. This review showcases the intrinsic ability of hybrid constructs to react to external or internal/physiological stimuli in the scope of developing sophisticated and intelligent systems with application-oriented features. Moreover, nanoparticle-hydrogel platforms are overviewed in the context of encoding stimuli-responsive cascades that recapitulate signaling interplays present in native biosystems. Collectively, recent breakthroughs in the design of stimuli-responsive nanocomposite hydrogels improve their potential for operating as advanced systems in different biomedical applications that benefit from tailored single or multi-responsiveness.     

Stimuli-Responsive Dynamic Metaholographic Displays with Designer Liquid Crystal Modulators

Flat optics, realized by the artificially created 2D material platform called optical metasurfaces, is currently undergoing a science-to-technology transition. However, “real-time” active operations of such flat optical devices remain yet unresolved. Here, liquid crystals (LCs)-integrated metaholograms for ultracompact dynamic holographic displays are proposed. The anisotropic nature of the LCs allows facile and repeatable manipulation of the polarization of light. Specifically designed (“designer”) LCs and efficient helicity-encoded metaholograms are combined to realize stimuli-responsive dynamic displays. The designer LC modulators are used as switches that enable a variety of external stimuli (e.g., electric field, heat, surface pressure) to operate holographic images in real-time. Such a dynamic metaholographic platform will provide a path to external stimuli-driven “smart” sensing and display applications such as hologram labels for temperature/pressure/touch monitoring and interactive holographic displays with haptic motion recognition.     

Engineering Nanorobots for Tumor-Targeting Drug Delivery: From Dynamic Control to Stimuli-Responsive Strategy

Nanotechnology has been widely applied to the fabrication of drug delivery systems in the past decades. Recently, with the progress made in microfabrication approaches, nanorobots are steadily becoming a promising means for tumor-targeting drug delivery. In general, nanorobots can be divided into two categories: nanomotors and stimuli-responsive nanorobots. Nanomotors are nanoscale systems with the ability to convert surrounding energies into mechanical motion, whereas stimuli-responsive nanorobots are featured with activatable capacity in response to various endogenous and exogenous stimulations. In this minireview, the dynamic control of nanomotors and the rational design of stimuli-responsive nanorobots are overviewed, with particular emphasis on their contribution to tumor-targeting therapy. Moreover, challenges and perspectives associated with the future development of nanorobots are presented.     

弱相互作用调控表面活性剂自组装(Ⅲ)——响应性表面活性剂

天然的或合成的两亲分子(表面活性剂)可以自组装形成多尺度的聚集体结构,比如胶束、囊泡、液晶和纤维等。在表面活性剂中引入功能性基团,借助外界环境(比如光、温度、pH、CO2、磁等)的改变可以实现对表面活性剂的聚集方式的调控。本文主要介绍响应性表面活性剂的种类、结构以及环境刺激与响应性能之间的关系。     

刺激响应型农药控释剂研发与应用进展

农药的长期低效使用增加了农业生产成本，造成大量农药流失，威胁食品安全与生态环境。利用农药缓控释技术对现有农药剂型进行改进是提高农药利用率的有效措施。刺激响应聚合物作为新兴载体，可以感受周边环境变化，从而响应并靶向控制释放有效成分。在医药领域，这类材料作为药物运载体的研究已相当广泛，在癌症的靶向治疗方面更是颇具成效。在农药控释领域的相关应用则处于基础研究阶段，仍然有一系列的因素限制着这类材料在农药控释领域的发展，比如载体成本、药物负载性能、体系稳定性、加工工艺的普适性及应用等。本文综述了刺激响应性聚合物应用于农药控释领域的研发现状，并对该类农药控释剂的应用前景进行了展望。     

Smart Poly (N-Isopropylacrylamide)-block-Poly (L-Lactide) Nanoparticles for Prolonged Release of Naltrexone

The authors synthesized core-shell smart nanoparticles composed of poly (N-isopropylacrylamide)-b-poly (L-lactide) (PNIPAAm–b-PLA) and developed for narcotic antagonists’ drug-delivery purpose. Micelle structure was verified by ¹H-NMR, FT-IR, and TEM. Effect of drug loading, polymer composition, and temperature on micelles morphology and diameter was investigated. Stimuli-responsive behaviors of these nanoparticles were determined using a three-factor full factorial experiment. Naltrexone was successfully incorporated into the PLA cores. By varying the PLA to PNIPAAm ratio, drug loading content, and release time were changed. Results suggest that smart micelles can be suitable for preparation of sustained release systems.     

Fluorescent Hydrogel–Textile Composite Material Synthesized by Photopolymerization

A fluorescent textile sensor and its capacities to detect pH changes in aqueous solutions have been reported. A new hydrogel-cotton fabric was obtained via surface initiated photopolymerization of 2-aminoethylmethacrylate hydrochloride, with N,N′-methylene-bis-acrylamide as a crosslinker, and fluorophore and modified eosin Y and N-methyldiethanolamine as photoinitiators. The synthesis of the modified eosin Y and a new 1,8-naphtalimide used as signal units in the hydrogel composite have been described. It has been found that the concentration of the photoinitiator affects the functional properties of the composite. pH variations influence the gel structure and this is transduced into fluorescence and color changes of the material.     

Growth factor delivery-based tissue engineering: general approaches and a review of recent developments

The identification and production of recombinant morphogens and growth factors that play key roles in tissue regeneration have generated much enthusiasm and numerous clinical trials, but the results of many of these trials have been largely disappointing. Interestingly, the trials that have shown benefit all contain a common denominator, the presence of a material carrier, suggesting strongly that spatio-temporal control over the location and bioactivity of factors after introduction into the body is crucial to achieve tangible therapeutic effect. Sophisticated materials systems that regulate the biological presentation of growth factors represent an attractive new generation of therapeutic agents for the treatment of a wide variety of diseases. This review provides an overview of growth factor delivery in tissue engineering. Certain fundamental issues and design strategies relevant to the material carriers that are being actively pursued to address specific technical objectives are discussed. Recent progress highlights the importance of materials science and engineering in growth factor delivery approaches to regenerative medicine.