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stimuli responsive materials

Yakup Ulusu, Gema Dura, Helen Waller, Matthew Benning, David Fulton, Jeremy Lakey, Daniel Thomas Peters
The ability to culture cells in three dimensions has many applications, from drug discovery to wound healing. 3D cell culture methods often require appropriate scaffolds that mimic the cellular environments of different tissue types. The choice of material from which these scaffolds are made is of paramount importance, as its properties will define the manner in which cells interact with the scaffold. Caf1 is a protein polymer that is secreted from its host organism, Yersinia pestis, to enable escape from phagocytosis...
June 20, 2017: Biomedical Materials
Alessandro Sorrenti, Jorge Leira-Iglesias, Akihiro Sato, Thomas M Hermans
Living systems use fuel-driven supramolecular polymers such as actin to control important cell functions. Fuel molecules like ATP are used to control when and where such polymers should assemble and disassemble. The cell supplies fresh ATP to the cytosol and removes waste products to sustain steady states. Artificial fuel-driven polymers have been developed recently, but keeping them in sustained non-equilibrium steady states (NESS) has proven challenging. Here we show a supramolecular polymer that can be kept in NESS, inside a membrane reactor where ATP is added and waste removed continuously...
June 19, 2017: Nature Communications
Lucia Corich, Marina Busetti, Vincenzo Petix, Sabina Passamonti, Antonella Bandiera
Elastin is a fibrous protein that confers elasticity to tissues such as skin, arteries and lung. It is extensively cross-linked, highly hydrophobic and insoluble. Nevertheless, elastin can be hydrolysed by bacterial proteases in infectious diseases, resulting in more or less severe tissue damage. Thus, development of substrates able to reliably and specifically detect pathogen-secreted elastolytic activity is needed to improve the in vitro evaluation of the injury that bacterial proteases may provoke. In this work, two human biomimetic elastin polypeptides, HELP and HELP1, as well as the matrices derived from HELP, have been probed as substrates for elastolytic activity detection...
June 14, 2017: Journal of Biotechnology
Qiaomei Chen, Xiaowen Yu, Zhiqiang Pei, Yang Yang, Yen Wei, Yan Ji
Smart polymers have been playing indispensable roles in our lives. However, it is challenging to combine more than three stimuli-responses or functionalities into one polymer, not to mention integrating multi-stimuli responsivity and multi-functionality at the same time. Vitrimers, an emerging type of materials, are covalently crosslinked networks that can be reprocessed but are still infusible and insoluble. Herein, we show that simply introducing oligoaniline into a vitrimer results in a covalently crosslinked material that can respond to six different stimuli (heat, light, pH, voltage, metal ions and redox chemicals) and perform six functions (shape memory, welding, healing, recycling, electro-chromism and adsorption of metal ions)...
January 1, 2017: Chemical Science
Yuki Nishida, Akiko Tanaka, Shota Yamamoto, Yudai Tominaga, Nobuaki Kunikata, Minoru Mizuhata, Tatsuo Maruyama
Supramolecular hydrogels are expected to have applications as novel soft materials in various fields owing to their designable functional properties. Here we developed an in-situ synthesis of supramolecular hydrogelators, which can trigger gelation of an aqueous solution without the need for temperature change. This was achieved by mixing two precursors, which induced the synthesis of a supramolecular gelator and its instantaneous self-assembly into nanofibers. We then performed the in-situ synthesis of the same supramolecular gelator at an oil/water interface to produce nanofibers that covered the surfaces of the oil droplets (nanofiber-stabilized oil droplets)...
June 13, 2017: Angewandte Chemie
Xiaodong Wu, Yangyang Han, Xinxing Zhang, Canhui Lu
Conductive polymer composites (CPCs) have been intensively exploited as remarkable liquid sensing materials based on variations in their conductivity under liquid stimuli. However, most advances in liquid sensing CPCs are limited to bulk materials. Due to the slow permeation of liquids into the compact CPCs, sluggish responses are inevitable for most existing CPC-based liquid sensing materials. Here, we developed a new class of liquid sensing materials via a hierarchical structure design. Specifically, a thin CPC layer with a segregated conductive network was coated on porous polyurethane (PU) skeletons by layer-by-layer assembly, forming an elaborately designed hierarchical structure in the prepared CPC@PU composites...
June 21, 2017: Physical Chemistry Chemical Physics: PCCP
Andrew Brandmaier, Sheng-Qi Hou, Wen H Shen
Continuous and error-free chromosome inheritance through the cell cycle is essential for genomic stability and tumor suppression. However, accumulation of aberrant genetic materials often causes the cell cycle to go awry, leading to malignant transformation. In response to genotoxic stress, cells employ diverse adaptive mechanisms to halt or exit the cell cycle temporarily or permanently. The intrinsic machinery of cycling, resting, and exiting shapes the cellular response to extrinsic stimuli whereas prevalent disruption of the cell cycle machinery in tumor cells often confers resistance to anti-cancer therapy...
June 8, 2017: Journal of Molecular Biology
Jue Deng, Yifan Xu, Sisi He, Peining Chen, Luke Bao, Yajie Hu, Bingjie Wang, Xuemei Sun, Huisheng Peng
Mechanically responsive materials that are able to sense and respond to external stimuli have important applications in soft robotics and the formation of artificial muscles, such as intelligent electronics, prosthetic limbs, comfort-adjusting textiles and miniature actuators for microfluidics. However, previous artificial muscles based on polymer materials are insufficient in generating large actuations, fast responses, diverse deformation modes and high cycle performances. To this end, carbon nanotubes (CNTs) are proposed as promising candidates to be assembled into artificial muscles, as they are lightweight, robust and have high surface-to-volume ratios...
July 2017: Nature Protocols
Zhale Atoufi, Payam Zarrintaj, Ghodratollah Hashemi Motlagh, Anahita Amiri, Zohreh Bagher, Seyed Kamran Kamrava
In this study, synthesis of a novel biocompatible stimuli-responsive conducting hydrogel based on agarose/alginate-aniline tetramer with the capability of a tailored electrically controlled drug-release for neuroregeneration is investigated. First, aniline tetramer is synthesized and grafted onto sodium alginate. Then, this material is added to agarose as an electrical conductivity modifier to obtain Agarose/alginate-aniline tetramer hydrogel. The synthesized materials are characterized by H NMR and FTIR. The hydrogels are prepared with varying content of aniline tetramer and their swelling-deswelling and shape memory behavior is evaluated...
June 14, 2017: Journal of Biomaterials Science. Polymer Edition
Livio Oboti, Sara Trova, Roberta Schellino, Marilena Marraudino, Natalie R Harris, Olubukola M Abiona, Mojca Stampar, Weihong Lin, Paolo Peretto
The vomeronasal system (VNS) is specialized in the detection of salient chemical cues triggering social and neuroendocrine responses. Such responses are not always stereotyped, instead, they vary depending on age, sex, and reproductive state, yet the mechanisms underlying this variability are unclear. Here, by analyzing neuronal survival in the first processing nucleus of the VNS, namely the accessory olfactory bulb (AOB), through multiple bromodeoxyuridine birthdating protocols, we show that exposure of female mice to male soiled bedding material affects the integration of newborn granule interneurons mainly after puberty...
2017: Frontiers in Neuroanatomy
Jiahao Xia, Feng Li, Shaobo Ji, Huaping Xu
Graphene oxide (GO) is an important two-dimensional material since it is water soluble and can be functionalized to adapt to different applications. However, the current covalent functionalization methods usually require hash conditions, long duration and sometimes even multi-steps, while noncovalent functionalization is inevitably unstable, especially under physiological environment where competing species exist. Diselenide bond is a dynamic covalent bond and can respond to both redox condition and visible light irradiation in a sensitive manner...
June 6, 2017: ACS Applied Materials & Interfaces
Luzhuo Chen, Mingcen Weng, Peidi Zhou, Lingling Zhang, Zhigao Huang, Wei Zhang
Carbon-based electrothermal or photothermal actuators have attracted intense attention recently. They can directly convert electrical or light energy into thermal energy and exhibit obvious deformations. However, if the actuation mechanism is only limited to thermal expansion, the deformation amplitude is difficult to increase further. Moreover, complex shape-deformation is still challenging. Although a few materials were reported to realize twisting or untwisting actuation by cutting the samples into strips along different orientations, each single strip could perform only one shape-deformation mode...
June 6, 2017: Nanoscale
Noriaki Ozaki, Hirotoshi Sakamoto, Taishi Nishihara, Toshihiko Fujimori, Yuh Hijikata, Ryuto Kimura, Stephan Irle, Kenichiro Itami
We report an electric-stimuli-responsive multifunctional material that can be readily made by simply mixing a hydrocarbon nanoring ([10]cycloparaphenylene: [10]CPP) and iodine ([10]CPP-I). Through applying electric stimulus, the assembled material [10]CPP-I is endowed with two attractive properties: turn-on electronic conductivity and white light emission. We determined that electric stimuli trigger the cascade formation of polyiodide chains inside the [10]CPP assembly through charge transfer, leading to the emergence of these fascinating properties...
June 6, 2017: Angewandte Chemie
Junhyuk Lee, Kang Hee Ku, Mingoo Kim, Jae Man Shin, Junghun Han, Chan Ho Park, Gi-Ra Yi, Se Gyu Jang, Bumjoon J Kim
Development of particles that change shape in response to external stimuli has been a long-thought goal for producing bioinspired, smart materials. Herein, the temperature-driven transformation of the shape and morphology of polymer particles composed of polystyrene-b-poly(4-vinylpyridine) (PS-b-P4VP) block copolymers (BCPs) and temperature-responsive poly(N-isopropylacrylamide) (PNIPAM) surfactants is reported. PNIPAM acts as a temperature-responsive surfactant with two important roles. First, PNIPAM stabilizes oil-in-water droplets as a P4VP-selective surfactant, creating a nearly neutral interface between the PS and P4VP domains together with cetyltrimethylammonium bromide, a PS-selective surfactant, to form anisotropic PS-b-P4VP particles (i...
June 5, 2017: Advanced Materials
Ibrahim El-Sherbiny, Islam Khalil, Isra Ali, Magdi Yacoub
Smart materials are those materials that are responsive to chemical (organic molecules, chemical agents or specific agents), biochemical (protein, enzymes, growth factors, substrates or ligands), physical (electric field, magnetic field, temperature, pH, ionic strength or radiation) or mechanical (pressure or mechanical stress) signals. These responsive materials interact with the stimuli by changing their properties or conformational structures in a predictable manner. Recently, smart polymers have been utilized in various biomedical applications...
June 21, 2017: Drug Development and Industrial Pharmacy
Shengwei Xiao, Yin Yang, Mingqiang Zhong, Hong Chen, Yanxian Zhang, Jintao Yang, Jie Zheng
Development of stimuli-responsive, shape-transformable materials is fundamentally and practically important for smart actuators. Herein, we design and synthesize a bilayer hydrogel by assembling a polycationic (polyMETAC/HEAA) layer with polyelectrolyte effect and a polyzwitterionic (polyVBIPS) layer with antipolyelectrolyte effect together. The bilayer hydrogels adopt a pseudo-double-network structure, and both polyelectrolyte and polyzwitterionic layers have salt-responsive swelling and shrinkage properties, but in a completely opposite way...
June 21, 2017: ACS Applied Materials & Interfaces
Hao Zeng, Owies M Wani, Piotr Wasylczyk, Arri Priimagi
Liquid crystal elastomers are among the best candidates for artificial muscles, and the materials of choice when constructing microscale robotic systems. Recently, significant efforts are dedicated to designing stimuli-responsive actuators that can reproduce the shape-change of soft bodies of animals by means of proper external energy source. However, transferring material deformation efficiently into autonomous robotic locomotion remains a challenge. This paper reports on a miniature inching robot fabricated from a monolithic liquid crystal elastomer film, which upon visible-light excitation is capable of mimicking caterpillar locomotion on different substrates like a blazed grating and a paper surface...
May 31, 2017: Macromolecular Rapid Communications
Wen Wang, Lining Yao, Chin-Yi Cheng, Teng Zhang, Hiroshi Atsumi, Luda Wang, Guanyun Wang, Oksana Anilionyte, Helene Steiner, Jifei Ou, Kang Zhou, Chris Wawrousek, Katherine Petrecca, Angela M Belcher, Rohit Karnik, Xuanhe Zhao, Daniel I C Wang, Hiroshi Ishii
Cells' biomechanical responses to external stimuli have been intensively studied but rarely implemented into devices that interact with the human body. We demonstrate that the hygroscopic and biofluorescent behaviors of living cells can be engineered to design biohybrid wearables, which give multifunctional responsiveness to human sweat. By depositing genetically tractable microbes on a humidity-inert material to form a heterogeneous multilayered structure, we obtained biohybrid films that can reversibly change shape and biofluorescence intensity within a few seconds in response to environmental humidity gradients...
May 2017: Science Advances
Cheng-Gen Qian, Yu-Lei Chen, Pei-Jian Feng, Xuan-Zhong Xiao, Mei Dong, Ji-Cheng Yu, Quan-Yin Hu, Qun-Dong Shen, Zhen Gu
Conjugated polymer nanomaterials (CPNs), as optically and electronically active materials, hold promise for biomedical imaging and drug delivery applications. This review highlights the recent advances in the utilization of CPNs in theranostics. Specifically, CPN-based in vivo imaging techniques, including near-infrared (NIR) imaging, two-photon (TP) imaging, photoacoustic (PA) imaging, and multimodal (MM) imaging, are introduced. Then, CPN-based photodynamic therapy (PDT) and photothermal therapy (PTT) are surveyed...
June 2017: Acta Pharmacologica Sinica
Zili Li, Miao Tang, Wei Bai, Ruke Bai
Carbon nanotubes can be used as promising reinforcement materials to improve the mechanical properties of hydrogels, but their poor dispersibility in aqueous solution severely limits their application in preparation of composite hydrogels. Therefore, to develop method for modification of carbon nanotubes is still highly desired. In this paper, a facile approach for preparation of the hydrophilic carbon nanotube was reported. The encapsulated multiwalled carbon nanotubes (E-CNT-PAA) with cross-linked shell structure were obatined through the self-assembly of the amphipathic azide diblock copolymers poly(acrylic acid)-b-poly(4-vinylbenzyl azide-co-styrene) (PAA-b-(PVBA-co-PS)), and the cross-linking of inside azide groups under UV irradiation...
June 5, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
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