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stimuli responsive materials

Giuseppe, Serena Riela, Rawil F Fakhrullin
Clays for drug delivery have been used from ancient time due to the large availability of clay minerals and their unprecedented properties. The empirical use of nanoclays from the past is converted in a stimulating scientific task aimed at building up nanoarchitectonic vehicles for drug delivery in a targeted and stimuli-responsive fashion. Here the historical aspects are discussed; next the modern examples of applications of different clay-based materials are discussed. A special focus is given to halloysite clay nanotubes, which are an emerging and very promising nanomaterial for drug-delivery purposes due to its special morphology and unique chemical properties...
July 2017: Therapeutic Delivery
Shasha Song, Yang Liu, Aixin Song, Zengdian Zhao, Hongsheng Lu, Jingcheng Hao
Stimuli-response magnetic hydrogels were prepared in the mixtures of magnetic surfactants, (CnTAFB(C), n=12, 14, 16), and chiral amphiphiles, sodium cholate (SC). The gelation behavior of CnTAFB(C)/SC were studied in detail. The results proved that the hydrophobicity of surfactants and the hydration radius (Rh) of anions played a vital role in the gelation process. The microstructure of the hydrogels were determined to be three-dimensional network of fibrous aggregates. The formation of the hydrogel fibrils was considered to be mainly driven by a delicate balance of multiple non-covalent interactions including hydrophobic interaction, electrostatic interaction, hydrogen bonding, van der Waals force, and the steric effect of SC molecule...
July 10, 2017: Journal of Colloid and Interface Science
Ting Wei, Wenjun Zhan, Qian Yu, Hong Chen
Smart biointerfaces with capability to regulate cell-surface interactions in response to external stimuli are of great interest for both fundamental research and practical applications. Smart surfaces with "ON/OFF" switchability for a single function such as cell attachment/detachment are well-known and useful, but the ability to switch between two different functions may be seen as the next level of "smart". In this work reported, a smart supramolecular surface capable of switching functions reversibly between bactericidal activity and bacteria-releasing ability in response to UV-visible light is developed...
July 20, 2017: ACS Applied Materials & Interfaces
Lefteris I Kosmidis, Kaare H Jensen
Stimuli-responsive materials that modify their shape in response to changes in environmental conditions-such as solute concentration, temperature, pH, and stress-are widespread in nature and technology. Applications include micro- and nanoporous materials used in filtration and flow control. The physiochemical mechanisms that induce internal volume modifications have been widely studied. The coupling between induced volume changes and solute transport through porous materials, however, is not well understood...
June 2017: Physical Review. E
Michika Onoda, Takeshi Ueki, Ryota Tamate, Mitsuhiro Shibayama, Ryo Yoshida
In the field of polymer science, many kinds of polymeric material systems that show a sol-gel transition have been created. However, most systems are unidirectional stimuli-responsive systems that require physical signals such as a change in temperature. Here, we report on the design of a block copolymer solution that undergoes autonomous and periodic sol-gel transition under constant conditions without any on-off switching through external stimuli. The amplitude of this self-oscillation of the viscosity is about 2,000 mPa s...
July 13, 2017: Nature Communications
Lei Zhang, Sourav Maity, Kai Liu, Qing Liu, Robert Göstl, Giuseppe Portale, Wouter H Roos, Andreas Herrmann
Over the last decades, water-based lyotropic liquid crystals of nucleic acids have been extensively investigated because of their important role in biology. Alongside, solvent-free thermotropic liquid crystals (TLCs) from DNA are gaining great interest, owing to their relevance to DNA-inspired optoelectronic applications. Up to now, however, only the smectic phase of DNA TLCs has been reported. The development of new mesophases including nematic, hexagonal, and cubic structures for DNA TLCs remains a significant challenge, which thus limits their technological applications considerably...
July 11, 2017: Small
J Conesa-Egea, J Gallardo-Martínez, S Delgado, J I Martínez, J Gonzalez-Platas, V Fernández-Moreira, U R Rodríguez-Mendoza, P Ocón, F Zamora, P Amo-Ochoa
A nonporous laminar coordination polymer of formula [Cu2 I2 (2-aminopyrazine)]n is prepared by direct reaction between CuI and 2-aminopyrazine, two industrially available building blocks. The fine tuning of the reaction conditions allows obtaining [Cu2 I2 (2-aminopyrazine)]n in micrometric and nanometric sizes with same structure and composition. Interestingly, both materials show similar reversible thermo- and pressure-luminescent response as well as reversible electrical response to volatile organic solvents such as acetic acid...
July 10, 2017: Small
Oleksandr S Bushuyev, Miho Aizawa, Atsushi Shishido, Christopher J Barrett
The development of stimuli-responsive polymers is among the key goals of modern materials science. The structure and properties of such switchable materials can be designed to be controlled via various stimuli, among which light is frequently the most powerful trigger. Light is a gentle energy source that can target materials remotely, and with extremely high spatial and temporal resolution easily and cheaply. Reversible light-control over molecular mechanical properties in particular has in recent years attracted great interest due to potential applications as optical-to-mechanical conversion actuators and 'devices', enabling 'molecular robotic machines'...
July 10, 2017: Macromolecular Rapid Communications
Danish J Malik, Ilya J Sokolov, Gurinder K Vinner, Francesco Mancuso, Salvatore Cinquerrui, Goran T Vladisavljevic, Martha R J Clokie, Natalie J Garton, Andrew G F Stapley, Anna Kirpichnikova
Against a backdrop of global antibiotic resistance and increasing awareness of the importance of the human microbiota, there has been resurgent interest in the potential use of bacteriophages for therapeutic purposes, known as phage therapy. A number of phage therapy phase I and II clinical trials have concluded, and shown phages don't present significant adverse safety concerns. These clinical trials used simple phage suspensions without any formulation and phage stability was of secondary concern. Phages have a limited stability in solution, and undergo a significant drop in phage titre during processing and storage which is unacceptable if phages are to become regulated pharmaceuticals, where stable dosage and well defined pharmacokinetics and pharmacodynamics are de rigueur...
May 14, 2017: Advances in Colloid and Interface Science
Jingsong Peng, Yiren Cheng, Antoni P Tomsia, Lei Jiang, Qunfeng Cheng
Nacre-inspired nanocomposites have attracted a great deal of attention in recent years because of their special mechanical properties and universality of the underlying principles of materials engineering. The ability to respond to external stimuli will augment the high toughness and high strength of artificial nacre-like composites and open new technological horizons for these materials. Herein, we fabricated robust artificial nacre based on montmorillonite (MMT) that combines robustness with reversible thermochromism...
July 17, 2017: ACS Applied Materials & Interfaces
Bijnaneswar Mondal, Aloke Kumar Ghosh, Partha Sarathi Mukherjee
A spiropyran decorated covalent organic cage (PC2) has been designed employing dynamic imine chemistry followed by imine bond reduction. The molecule is capable of altering its colour upon exposure to external stimuli like heat and light. Construction of a 3D organic cage introduces a new piece to the system by swapping of close form to open form in solid state withdiverse colour change. Moreover, this material has high chemical stability and is capable of reversible stimuli-responsive colour change without any degradation for an extended period...
July 5, 2017: Journal of Organic Chemistry
Zhi-Hao Guo, Xiao-Feng Liu, Jian-She Hu, Li-Qun Yang, Zhang-Pei Chen
The morphological control of polymer micellar aggregates is an important issue in applications such as nanomedicine and material science. Stimuli responsive soft materials have attracted significant attention for their well-controlled morphologies. However, despite extensive studies, it is still a challenge to prepare nanoscale assemblies with responsive behaviors. Herein, a new chiral liquid crystal (LC) aliphatic polycarbonate with side chain bearing diosgenyl mesogen, named mPEG43-PMCC25-P(MCC-DHO)15, was synthesized through the ring-opening polymerization and coupling reaction...
July 4, 2017: Nanomaterials
Ming-Xue Wu, Xin Wang, Ying-Wei Yang
Researches on cargo delivery systems have received burgeoning attention and advanced rapidly. For synthetic nanodevices, polymer nanoassemblies and their inorganic-organic hybrid materials, especially smart mesoporous silica nanoparticle (MSN)-polymer hybrids (e. g., MSN@PGMAs), have attracted increasing attention in recent years. Their superior characteristics and unique features such as dynamic transition of morphology endow them the ability to efficiently entrap cargo molecules and undergo smart cargo delivery and release in response to various external stimuli...
July 4, 2017: Chemical Record: An Official Publication of the Chemical Society of Japan ... [et Al.]
Huang Dingming, Lu Qian, Liao Qian, Ye Ling, Zhou Xuedong
Dental pulp tissue plays a role in forming dentin, providing nutrition, conducting pain, and generating protective responses to environmental stimuli. Bacterial infection is the main cause of pulp disease, where histopathological changes are the histological basis for determining the choice of treatment and the evaluation of therapeutic effect. Thus, particular attention should be given to eliminate infection, as well as preserve and maintain pulpal health in teeth that show reversible or limited pulpal injuries...
June 1, 2017: Hua Xi Kou Qiang Yi Xue za Zhi, Huaxi Kouqiang Yixue Zazhi, West China Journal of Stomatology
Samer Gnaim, Doron Shabat
Self-immolative polymers are distinctive materials able to disassemble in a domino-like mechanism from head-to-tail upon a triggering event induced by an external stimulus. We have developed an effective molecular method to intrinsically assimilate a chemiluminescence turn-ON mechanism with a domino-like fragmentation mechanism. A unique molecular unit was synthesized, which could combine the abilities of executing the duel function of quinone-methide elimination and chemiexcitation. Incorporation of this unit as a monomer, results with the first class of stimuli-responsive self-immolative polymers with amplified chemiluminescence output...
July 3, 2017: Journal of the American Chemical Society
Nayereh Dadoo, Samuel B Landry, Jonathan D Bomar, William M Gramlich
Carboxymethyl cellulose (CMC) is functionalized with norbornene groups to undergo thiol-norbornene cross-linking reactions. Hydrogels synthesized from a single norbornene-modified carboxymethyl cellulose (NorCMC) via a light-initiated thiol-ene cross-linking reaction with a variety of dithiol cross-linkers yield hydrogels with a tunable compression modulus ranging from 1.7 to 103 kPa. Additionally, thermoresponsiveness is spatiotemporally imparted to NorCMC hydrogels by photopatterning a dithiol-terminated poly(N-isopropyl acrylamide) cross-linker, enabling swelling and topological control of the hydrogels as a function of incubation temperature...
July 3, 2017: Macromolecular Bioscience
Natalia L Calvo, Rubén M Maggio, Teodoro S Kaufman
The understanding of materials and processes is a requirement when it comes to build quality into pharmaceutical products. This can be achieved through the development of rapid, efficient and versatile analytical methods able to perform qualification or quantification tasks along the manufacturing and control process. Process monitoring, capable of providing reliable real-time insights into the processes performance during the manufacturing of solid dosage forms, are the key to improve such understanding. In response to these demands, in recent times multivariate chemometrics algorithms have been increasingly associated to different analytical techniques, mainly vibrational spectroscopies [Raman, mid-infrared (MIR), near-infrared (NIR)], but also ultraviolet-visible (UV-vis) spectroscopy, X-ray powder diffraction and other methodologies...
June 15, 2017: Journal of Pharmaceutical and Biomedical Analysis
Eric A Appel, Frank Biedermann, Dominique Hoogland, Jesús Del Barrio, Max D Driscoll, Sam Hay, David J Wales, Oren A Scherman
Kinetics and thermodynamics in supramolecular systems are intimately linked, yet both are independently important for application in sensing assays and stimuli-responsive switching/self-healing of materials. Host-guest interactions are of particular interest in many water-based materials, sensing and drug delivery applications. Herein we investigate the binding dynamics of a variety of electron-rich aromatic moieties forming hetero-ternary complexes with the macrocycle cucurbit[8]uril (CB[8]) and an auxiliary guest, dimethyl viologen, with high selectivity and equilibrium binding constants (Keq up to 10(14)M(-2))...
June 29, 2017: Journal of the American Chemical Society
Hui Yang, Wan Ru Leow, Ting Wang, Juan Wang, Jiancan Yu, Ke He, Dianpeng Qi, Changjin Wan, Xiaodong Chen
Compared with traditional stimuli-responsive devices with simple planar or tubular geometries, 3D printed stimuli-responsive devices not only intimately meet the requirement of complicated shapes at macrolevel but also satisfy various conformation changes triggered by external stimuli at the microscopic scale. However, their development is limited by the lack of 3D printing functional materials. This paper demonstrates the 3D printing of photoresponsive shape memory devices through combining fused deposition modeling printing technology and photoresponsive shape memory composites based on shape memory polymers and carbon black with high photothermal conversion efficiency...
June 29, 2017: Advanced Materials
Anne Helene Gelebart, Dirk Jan Mulder, Michael Varga, Andrew Konya, Ghislaine Vantomme, E W Meijer, Robin L B Selinger, Dirk J Broer
Oscillating materials that adapt their shapes in response to external stimuli are of interest for emerging applications in medicine and robotics. For example, liquid-crystal networks can be programmed to undergo stimulus-induced deformations in various geometries, including in response to light. Azobenzene molecules are often incorporated into liquid-crystal polymer films to make them photoresponsive; however, in most cases only the bending responses of these films have been studied, and relaxation after photo-isomerization is rather slow...
June 28, 2017: Nature
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