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21.
Jing Luo Jingxin Meng Zhen Gu Luying Wang Feilong Zhang Shutao Wang 《Small (Weinheim an der Bergstrasse, Germany)》2019,15(15)
Self‐organization is a fundamental and indispensable process in a living system. To understand cell behavior in vivo such as tumorigenesis, 3D cellular aggregates, instead of 2D cellular sheets, have been employed as a vivid in vitro model for self‐organization. However, most focus on the macroscale wetting and fusion of cellular aggregates. In this study, it is reported that self‐organization of cells from simple to complex aggregates can be induced by multiscale topography through confined templates at the macroscale and cell interactions at the nanoscale. On the one hand, macroscale templates are beneficial for the organization of individual cells into simple and complex cellular aggregates with various shapes. On the other hand, the realization of these macro‐organizations also depends on cell interactions at the nanoscale, as demonstrated by the intimate contact between nanoscale pseudopodia stretched by adjacent frontier cells, much like holding hands and by the variation in the intermolecular interactions based on E‐cadherin. Therefore, these findings may be very meaningful for clarifying the organizational mechanism of tumor development, tissue engineering and regenerative medicine. 相似文献
22.
Cuicui Ding Min Zhang Miao Ma Jiaojiao Zheng Qili Yang Ren Feng 《Polymer International》2019,68(8):1468-1477
Hydrogels with environment‐sensitive properties have great potential applications in the controlled drug release field. In this paper, hybrid hydrogels with semi‐interpenetrating polymer networks (semi‐IPNs), composed of poly(N‐isopropylacrylamide) (PNIPAM) as the thermo‐sensitive component by in situ polymerization and self‐assembled collagen nanofibrils as the pH‐sensitive framework, were prepared for controlled release of methyl violet as a model drug. From Fourier transform infrared spectroscopy and scanning electron microscopy, it was indicated that the crosslinking of PNIPAM in the presence of collagen nanofibrils led to the formation of semi‐IPNs with homogeneous porous structure, and the semi‐IPNs showed improved thermal stability and elastic properties compared with the native collagen as determined using differential scanning calorimetry and rheologic measurements. Furthermore, the semi‐IPNs possessed swelling behaviors quite different from those of neat collagen or PNIPAM hydrogel under various pH values and temperatures. Correspondingly, as expected, the drug release behavior in vitro for semi‐IPNs performed variously compared with that for single‐component semi‐IPNs, which revealed the tunable performance of semi‐IPNs for release ability. Finally the thermo‐ and pH‐responsive mechanism of the semi‐IPNs was illuminated to provide guidance for the application of the thermo‐ and pH‐sensitive collagen‐based hybrid hydrogels in controlled drug delivery systems. © 2019 Society of Chemical Industry 相似文献
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This review focuses on the recent research progress in the multi-component assembly of luminescent rare earth hybrid materials, which is based on the luminescent rare earth compounds and two or more other building units, including the other photoactive species. It covers the multi-component luminescent rare earth hybrids which was assembled with different (a) organic-inorganic polymeric units, (b) nanoporous units, (c) nanoparticle composites or (d) other developing special units. Finally, future challenges and opportunities in this field are discussed. Herein it mainly focuses on the work of Yan's group in recent years. 相似文献
25.
Kylie B. Manning Nicholas Wyatt Lindsey Hughes Adam Cook Nicholas H. Giron Estevan Martinez Christopher G. Campbell Mathias C. Celina 《大分子材料与工程》2019,304(3)
The use of self‐assembling, pre‐polymer materials in 3D printing is rare, due to difficulties of facilitating printing with low molecular weight species and preserving their reactivity and/or functions on the macroscale. Akin to 3D printing of small molecules, examples of extrusion‐based printing of pre‐polymer thermosets are uncommon, arising from their limited rheological tuneability and slow reactions kinetics. The direct ink write (DIW) 3D printing of a two‐part resin, Epon 828 and Jeffamine D230, using a self‐assembly approach is reported. Through the addition of self‐assembling, ureidopyrimidinone‐modified Jeffamine D230 and nanoclay filler, suitable viscoelastic properties are obtained, enabling 3D printing of the epoxy–amine pre‐polymer resin. A significant increase in viscosity is observed, with an infinite shear rate viscosity of approximately two orders of magnitude higher than control resins, in addition to, an increase in yield strength and thixotropic behavior. Printing of simple geometries is demonstrated with parts showing excellent interlayer adhesion, unachievable using control resins. 相似文献
26.
Control of the 1D self‐assembly pattern of colloidal quantum dots (QDs) on PbSO4 nanoribbon (NRb) templates is achieved. The internal structure of the NRbs is investigated by X‐ray diffraction, revealing the isotropic packing of the PbSO4 nanoclusters in the NRbs. Colloidal QDs in a chloroform/hexane mixture are adsorbed onto the region close to the edges of the NRbs and form a 1D assembly of straight single line or double lines by controlling the amount of OAm. This is the first demonstration of a densely packed 1D self‐assembly of colloidal QDs with a straight line pattern without the use of any molecular bridge or adhesive. Atomic force microscopy measurements of the NRbs show depressions in the phase profile along the width of the NRbs, corresponding to the position of the 1D QD chain. The amount of adsorbed QDs on the NRbs in solution decreases as the addition of OAm increases, suggesting that additional OAm prevents interaction between the QDs and NRbs but facilitates the uniform adsorption of the 1D assembly. The low‐dimensional self‐assembly of colloidal QDs in this study opens up the possibility for the creation of anisotropically assembled QD superstructures. 相似文献
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Injection of bionic synovial fluid (BSF) is a conventional method to improve the lubricity of artificial joints, but BSF cannot maintain long due to the dilution and degradation of BSF in human body. To prolong the effectiveness of hyaluronic acid (HA), which is the major component of BSF, this study applies a temperature‐sensitive poly(?‐caprolactone)–poly(ethylene glycol)–poly(?‐caprolactone) (PCEC) hydrogel loaded with HA to achieve long‐term lubrication. In addition, Fourier transform infrared, nuclear magnetic resonance analysis, X‐ray diffraction, scanning electron microscopy (SEM), and gel permeation chromatography spectra were used to analyze the structure of the synthetic hydrogel. Rheological test and test tube inverting method were used to characterize the thermosensitivity. The lubrication properties of the released solution were characterized by UV–vis, tribological tests, SEM, and 3D laser confocal scanning microscope. The experimental results reveal that the triblock PCEC hydrogel contains both hydrophilic block and hydrophobic block, and both PCEC and PCEC/HA hydrogels have phase‐changed effect when the temperature increases from room temperature to body temperature. Moreover, the friction coefficient of the released solution from PCEC/HA hydrogel is approximatively 38% lower than that of phosphate buffer saline. And the ability of shear resistance and creep recovery of PCEC/HA hydrogel are better than that of PCEC hydrogel. This study provides an effective approach to achieve long‐time lubrication effect for artificial joints. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46228. 相似文献
30.
Solvent‐Controlled Assembly of Aromatic Glutamic Dendrimers for Efficient Luminescent Color Conversion 下载免费PDF全文
《Advanced functional materials》2018,28(34)
A binary supramolecular system where self‐sorting and coassembly behavior can be switched by changing the solvent polarity is hereby reported. Glutamic dendron is separately conjugated with pyrene and naphthalimide luminophores through an alkyl spacer. The resulting structurally similar building units can self‐assemble into one‐dimensional micro/nanostructures with hexagonal and lamellar packing, respectively. Varying solvents from polar aqueous solution to nonpolar decane is evidenced to profoundly inverse the superchirality and switch self‐sorted assembly to coassembly of the two building blocks. The moisture sensitivity of the naphthalimide moiety is considered the primary driving force for the self‐sorting phenomenon in aqueous solution, resulting in inevitable hydration to repel its stacking with hydrophobic pyrene moiety. On the other hand, the naphthalimide unit can integrate segmentally with the pyrene unit in decane, greatly facilitating the nanofiber growth and supramolecular gel formation along with improved energy transfer efficiency between luminophores. As a result, the coassembly‐based thin films show efficient luminescent color conversion upon the UV light irradiation. This research presents a useful route for the fabrication of controllable solution‐processed light emitting devices from self‐assembled multicomponent systems. 相似文献