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stimuli responsive materials

Lucas R Parent, Evangelos Bakalis, Abelardo Ramírez-Hernández, Jacquelin K Kammeyer, Chiwoo Park, Juan de Pablo, Francesco Zerbetto, Joseph P Patterson, Nathan C Gianneschi
Amphiphilic small molecules and polymers form commonplace nanoscale macromolecular compartments and bilayers, and as such are truly essential components in all cells and in many cellular processes. The nature of these architectures, including their formation, phase changes, and stimuli-response behaviors, is necessary for the most basic functions of life, and over the past half-century, these natural micellar structures have inspired a vast diversity of industrial products, from biomedicines to detergents, lubricants, and coatings...
November 17, 2017: Journal of the American Chemical Society
Chao Wei, Yan Zhang, Bingkun Yan, Yue Xu, Zhengzhen Du, Meidong Lang
Sulfur/selenium containing cyclic carbonate monomers (MR) are designed and synthesized by enzyme catalyzed intermolecular macro-ring closure of related diols. The proposed synthetic strategy is tolerant of other functionalities such as N-substituted groups. The ring opening polymerization (ROP) of MR occurs readily as a versatile route to generate a new family of main chain sulfur/selenium substituted aliphatic polycarbonates (PR) with predictable molecular weights (MW), narrow molecular-weight distribution and controlled copolymer composition...
November 15, 2017: Chemistry: a European Journal
Samala Murali Mohan Reddy, Pramod Dorishetty, George Augustine, Abhijit P Deshpande, Niraikulam Ayyadurai, Ganesh Shanmugam
Charge-transfer (CT) gel materials obtained from low-molecular-weight (LMW) compounds through a supramolecular self-assembly approach have received fascinating attention by many researchers because of their interesting material property and potential applications. However, most of the CT gel materials constructed were of organogels while the construction of CT gels in the form of a hydrogel is a challenge because of the solubility issue in water, which considerably limits the use of CT hydrogels. Herein, for the first time, we report a new LMW gelator [N(α)-(fluorenylmethoxycarbonyl)-N(ε)-(δ-butyric-1-pyrenyl)-l-lysine, (FmKPy)], composed of two functional moieties such as fluorenylmethoxycarbonyl and pyrene, which not only parade both hydro and organo (ambidextrous) supramolecular gel formation but also exhibit CT ambidextrous gels when mixed with an electron acceptor such as 2,4,7-trinitro-9-fluorenone (TNF)...
November 14, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
Julian R Silverman, Qize Zhang, Nabendu B Pramanik, Malick Samateh, Travis M Shaffer, Sai Sateesh Sagiri, Jan Grimm, George John
Recent interest in detecting visible photons that emanate from interactions of ionizing radiation with matter have spurred the development of multifunctional materials that amplify this optical signal from radiotracers. Tailored stimuli-responsive systems may be paired with diagnostic radionuclides to improving surgical guidance and aid in detecting therapeutic radionuclides otherwise difficult to image with conventional nuclear medicine approaches. Since light emanating from these interactions is typically low in intensity and blue-weighted (i...
November 14, 2017: ACS Applied Materials & Interfaces
Liwei Yan, Mingqian Lv, Chunjiao Su, Leihao Zheng, Jialing Li, Zhongbin Ye
Herein, a novel type of two-component supramolecular adsorbent, 2-OA, was developed based on non-covalent interactions using tetrazolyl derivative with octadecylamine (OA) and fully characterized using a number of structural and spectral techniques. The self-assembled 2-OA gels displayed remarkable stimuli-responsiveness as well as shape-persistent and self-healing properties. In addition, it was found that the adsorbent 2-OA was able to remove dyes (10 kinds of cationic and anionic dyes) and metal ions (Cu(2+) and Fe(2+)) simultaneously from wastewater owing to synergistic electrostatic attraction, hydrogen-bonding, and hydrophobic and coordination interactions...
November 13, 2017: Soft Matter
A P G Castro, D Lacroix
Scaffolds are used in diverse tissue engineering applications as hosts for cell proliferation and extracellular matrix formation. One of the most used tissue engineering materials is collagen, which is well known to be a natural biomaterial, also frequently used as cell substrate, given its natural abundance and intrinsic biocompatibility. This study aims to evaluate how the macroscopic biomechanical stimuli applied on a construct made of polycaprolactone scaffold embedded in a collagen substrate translate into microscopic stimuli at the cell level...
November 11, 2017: Biomechanics and Modeling in Mechanobiology
Cheng Zhang, Jheng-Wun Su, Heng Deng, Yunchao Xie, Zheng Yan, Jian Lin
Assembly of three-dimensional (3D) architectures with defined configurations has important applications in broad areas. Among various approaches of constructing 3D structures, stress-driven assembly provides the capabilities of creating 3D architectures in a broad range of functional materials with unique merits. However, 3D architectures built via previous methods are either simple, irreversible or not free-standing. Furthermore, the substrates employed for the assembly remain flat, thus not involved as parts of the final 3D architectures...
November 8, 2017: ACS Applied Materials & Interfaces
Elizaveta I Anastasova, Vladimir Ivanovski, Anna F Fakhardo, Artem I Lepeshkin, Suheir Omar, Andrey S Drozdov, Vladimir V Vinogradov
A magnetite-only hydrogel was prepared for the first time by weak base mediated gelation of stable magnetite hydrosols at room temperature. The hydrogel consists of 10 nm magnetite nanoparticles linked by interparticle Fe-O-Fe bonds and has the appearance of a dark-brown viscous thixotropic material. The water content in the hydrogel could be up to 93.6% by mass while volume fraction reaches 99%. The material shows excellent biocompatibility and minor cytotoxic effects at concentrations up to 207 μg mL(-1)...
November 8, 2017: Soft Matter
Koryna Lewandowska, Barbara Wachowicz, Tadeusz Marek, Halszka Oginska, Magdalena Fafrowicz
Across a wide range of tasks, cognitive functioning is affected by circadian fluctuations. In this study, we investigated diurnal variations of working memory performance, taking into account not only hits and errors rates, but also sensitivity (d') and response bias (c) indexes (established by signal detection theory). Fifty-two healthy volunteers performed four experimental tasks twice - in the morning and in the evening (approximately 1 and 10 h after awakening). All tasks were based on Deese-Roediger-McDermott paradigm version dedicated to study working/short-term memory distortions...
November 7, 2017: Chronobiology International
Hirotaka Koga, Masaya Nogi, Akira Isogai
Functional molecules play a significant role in the development of high-performance composite materials. Functional molecules should be well dispersed (ideally dissolved) and supported within an easy-to-handle substrate to take full advantage of their functionality and ensure easy handling. However, simultaneously achieving the dissolution and support of functional molecules remains a challenge. Herein, we propose the combination of a nonvolatile ionic liquid and an easy-to-handle cellulose paper substrate for achieving this goal...
November 13, 2017: ACS Applied Materials & Interfaces
Kamalesh Prasad, Dibyendu Mondal, Mukesh Sharma, Mara G Freire, Chandrakant Mukesh, Jitkumar Bhatt
Ion gels and self-healing gels prepared using ionic liquids (ILs) and deep eutectic solvents (DESs) have been largely investigated in the past years due to their remarkable applications in different research areas. Herewith we provide an overview on the ILs and DESs used for the preparation of ion gels, highlight the preparation and physicochemical characteristics of stimuli responsive gel materials based on co-polymers and biopolymers, with special emphasis on polysaccharides and discuss their applications...
January 15, 2018: Carbohydrate Polymers
Lubna H Abdullah, Raymond Coakley, Megan J Webster, Yunxiang Zhu, Robert Tarran, Giorgia Radicioni, Mehmet Kesimer, Richard C Boucher, C William Davis, Carla M P Ribeiro
RATIONALE: Cystic fibrosis (CF) airways disease produces a muco-obstructive lung phenotype characterized by airways mucus plugging, epithelial mucous cell metaplasia/hyperplasia, chronic infection and inflammation. Simultaneous biochemical and functional in vivo studies of mucin synthesis and secretion from CF airways are not available. In vitro translational models may quantitate differential CF vs. normal mucin and fluid secretory responses to infectious/inflammatory stimuli. OBJECTIVES: We tested the hypothesis that CF airways exhibit defective epithelial fluid, but not mucin, secretory responses to bacterial/inflammatory host products...
November 3, 2017: American Journal of Respiratory and Critical Care Medicine
Gongyuan Liu, Jianhua Zou, Qianyun Tang, Xiaoyan Yang, Ye-Wei Zhang, Qi Zhang, Wei Huang, Peng Chen, Jinjun Shao, Xiaochen Dong
Ti3C2 MXene is a new two-dimensional material exhibiting a variety of novel properties including good photothermal effect, and the capability of Ti3C2 for multimodal tumor therapy is in urgent need of development. Herein, ultrathin Ti3C2 MXene nanosheets (~100 nm) have been synthesized by supplying additive Al3+ to avoid Al loss and employed as a photothermal/photodynamic agent for cancer therapy. The as-obtained nanosheets exhibit outstanding mass extinction coefficient (28.6 Lg-1 cm-1 at 808 nm), superior photothermal conversion efficiency (~58...
November 3, 2017: ACS Applied Materials & Interfaces
Jin Zhang, Ting Zheng, Emine Alarçin, Batzaya Byambaa, Xiaofei Guan, Jianxun Ding, Yu Shrike Zhang, Zhongming Li
Stimuli-responsive porous polymer materials have promising biomedical application due to their ability to trap and release biomacromolecules. In this work, a class of highly porous electrospun fibers is designed using polylactide as the polymer matrix and poly(ethylene oxide) as a porogen. Carbon nanotubes (CNTs) with different concentrations are further impregnated onto the fibers to achieve self-sealing functionality induced by photothermal conversion upon light irradiation. The fibers with 0.4 mg mL(-1) of CNTs exhibit the optimum encapsulation efficiency of model biomacromolecules such as dextran, bovine serum albumin, and nucleic acids, although their photothermal conversion ability is slightly lower than the fibers with 0...
November 2, 2017: Small
Yuan Wang, Xue-Yin Zhang, Yan-Ling Luo, Feng Xu, Ya-Shao Chen, Yu-Yu Su
BACKGROUND: Stimuli-responsive polymer materials are a new kind of intelligent materials based on the concept of bionics, which exhibits more significant changes in physicochemical properties upon triggered by tiny environment stimuli, hence providing a good carrier platform for antitumor drug delivery. RESULTS: Dual stimuli-responsive Fe3O4 graft poly(acrylic acid)-block-poly(2-methacryloyloxyethyl ferrocenecarboxylate) block copolymers (Fe3O4-g-PAA-b-PMAEFC) were engineered and synthesized through a two-step sequential reversible addition-fragmentation chain transfer polymerization route...
October 27, 2017: Journal of Nanobiotechnology
Samuel Tobias Zimmermann, Diederik W R Balkenende, Anna Lavrenova, Christoph Weder, Jürgen Brugger
The miniaturization of nanometer-sized multicolor fluorescent features is of continuous significance for counterfeit security features, data storage, and sensors. Recent advances in engineering of stimuli-responsive supramolecular polymeric materials that respond upon exposure to heat or mechanical force by changing their fluorescence characteristics open new opportunities as functional lithographic resists. Here, we demonstrate the patterning of a thermochromic supramolecular material by thermal scanning probe lithography (t-SPL), an emerging nanofabrication technique, which allows for ultrafast indentation with a heated probe, resulting in both fluorescent and topographic nanofeatures...
November 14, 2017: ACS Applied Materials & Interfaces
Joseph J Pancrazio, Felix Deku, Atefeh Ghazavi, Allison M Stiller, Rashed Rihani, Christopher L Frewin, Victor D Varner, Timothy J Gardner, Stuart F Cogan
OBJECTIVES: Neural stimulation is well-accepted as an effective therapy for a wide range of neurological disorders. While the scale of clinical devices is relatively large, translational, and pilot clinical applications are underway for microelectrode-based systems. Microelectrodes have the advantage of stimulating a relatively small tissue volume which may improve selectivity of therapeutic stimuli. Current microelectrode technology is associated with chronic tissue response which limits utility of these devices for neural recording and stimulation...
October 27, 2017: Neuromodulation: Journal of the International Neuromodulation Society
Jamel Ali, U Kei Cheang, James D Martindale, Mehdi Jabbarzadeh, Henry C Fu, Min Jun Kim
Wirelessly controlled nanoscale robots have the potential to be used for both in vitro and in vivo biomedical applications. So far, the vast majority of reported micro- and nanoscale swimmers have taken the approach of mimicking the rotary motion of helical bacterial flagella for propulsion, and are often composed of monolithic inorganic materials or photoactive polymers. However, currently no man-made soft nanohelix has the ability to rapidly reconfigure its geometry in response to multiple forms of environmental stimuli, which has the potential to enhance motility in tortuous heterogeneous biological environments...
October 26, 2017: Scientific Reports
Adriaan Spruyt, Jan De Houwer
We introduce the (extrinsic) relational Simon task as a tool for capturing automatic relational stimulus processing. In three experiments, participants responded to a perceptual relation between two stimuli. Results showed that participants were faster and more accurate to respond when the (task-irrelevant) conceptual relation between these stimuli was compatible (rather than incompatible) with the (extrinsic) relational meaning of the required responses. This effect was replicated irrespective of the type of stimulus materials used, irrespective of the similarity between the relational information that was task-relevant and the relational information that was task-irrelevant, and irrespective of the complexity of the task-irrelevant relational information...
2017: PloS One
Jens Hjortkjær, Tanja Kassuba, Kristoffer H Madsen, Martin Skov, Hartwig R Siebner
In everyday sound environments, we recognize sound sources and events by attending to relevant aspects of an acoustic input. Evidence about the cortical mechanisms involved in extracting relevant category information from natural sounds is, however, limited to speech. Here, we used functional MRI to measure cortical response patterns while human listeners categorized real-world sounds created by objects of different solid materials (glass, metal, wood) manipulated by different sound-producing actions (striking, rattling, dropping)...
October 23, 2017: Cerebral Cortex
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