Nature Communications, Published online: 24 October 2019; doi:10.1038/s41467-019-12848-5
The activation of drugs within cellular systems may provide targeted therapies for cancer. Here, the authors make a drug delivery system that is activated within the cell and exploits XIAP expression to cleave a linker region, resulting in the self-assembly of the system and drug release within cancer cells.Yingke_Wu
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A tumour-selective cascade activatable self-detained system for drug delivery and cancer imaging
Catalysis-Driven Self-Thermophoresis of Janus Plasmonic Nanomotors
Abstract
It is highly demanding to design active nanomotors that can move in response to specific signals with controllable rate and direction. A catalysis-driven nanomotor was constructed by designing catalytically and plasmonically active Janus gold nanoparticles (Au NPs), which generate an asymmetric temperature gradient of local solvent surrounding NPs in catalytic reactions. The self-thermophoresis behavior of the Janus nanomotor is monitored from its inherent plasmonic response. The diffusion coefficient of the self-thermophoresis motion is linearly dependent on chemical reaction rate, as described by a stochastic model.
Self-propulsion of a Janus plasmonic nanomotor is presented that is driven by a chemical reaction. The mechanism of self-phoretic motion is explained as self-thermophoresis, and a stochastic model was developed to describe the relation between the diffusion coefficients of self-thermophoresis motion with chemical reaction rate.
Effect of Alkylation on the Cellular Uptake of Polyethylene Glycol-Coated Gold Nanoparticles
Yingke_WuEffect of Alkylation on the Cellular Uptake of Polyethylene Glycol-Coated Gold Nanoparticles
Scale-Up Procedure for the Efficient Synthesis of Highly Pure Cyclic Poly(ethylene glycol)
Yingke_WuEfficient Synthesis of Highly Pure Cyclic Poly(ethylene glycol)
A Novel Design of Multi-Mechanoresponsive and Mechanically Strong Hydrogels
Yingke_WuA Novel Design of Multi-Mechanoresponsive and Mechanically Strong Hydrogels
A newly developed polyacrylamide-co-methyl acrylate/spiropyran (SP) hydrogel crosslinked by SP mechanophore demonstrates multi-stimuli-responsive and mechanically strong properties. The hydrogels not only exhibit thermo-, photo-, and mechano-induced color changes, but also achieve super-strong mechanical properties (tensile stress of 1.45 MPa, tensile strain of ≈600%, and fracture energy of 7300 J m−2). Due to a reversible structural transformation between spiropyran (a ring-close) and merocyanine (a ring-open) states, simple exposure of the hydrogels to white light can reverse color changes and restore mechanical properties. The new design approach for a new mechanoresponsive hydrogel is easily transformative to the development of other mechanophore-based hydrogels for sensing, imaging, and display applications.
A newly developed poly(acrylamide-co-methyl acrylate)/spiropyran hydrogel with multi-stimuli-responsive and mechanically strong properties is presented. The resulting hydrogel exhibits reversible changes in color response and mechanical properties, making it promising for sensing, imaging, and display applications.
Inside Back Cover: Synthetic Channel Specifically Inserts into the Lipid Bilayer of Gram-Positive Bacteria but not that of Mammalian Erythrocytes (Angew. Chem. Int. Ed. 11/2017)
Yingke_WuInserts into the Lipid Bilayer of Gram-Positive Bacteria but not that of Mammalian Erythrocytes
Synthetic transmembrane channels are rationally designed molecules that can transport ions by formation of nanopores that span the lipid bilayer, and provide an alternative strategy for the development of membrane-active antimicrobials. However, few such channels show membrane selectivity. In their Communication on page 2999 ff., J.-L. Hou and co-workers report a channel that is able to specifically insert into the lipid bilayers of Gram-positive bacteria but not into those of mammalian erythrocytes.
Thermoplastic High Strain Multishape Memory Polymer: Side-Chain Polynorbornene with Columnar Liquid Crystalline Phase
Yingke_WuMultishape Memory Polymer
A thermoplastic high strain multishape memory polymer can be fabricated using a hemiphasmid side-chain polynorbornene (P1) with hexagonal columnar liquid crystalline (ΦH) phase. Without any chemical crosslinks, P1 can memorize multiple temporary shapes with high strain and exhibit excellent shape fixity and shape recovery. As the building blocks of ΦH, the multichain columns in P1 act as robust physical crosslinks.
A General Method for Selective Recognition of Monosaccharides and Oligosaccharides in Water
Yingke_WuSelective Recognition
Membrane Insertion of a Dinuclear Polypyridylruthenium(II) Complex Revealed by Solid-State NMR and Molecular Dynamics Simulation: Implications for Selective Antibacterial Activity
Yingke_WuSelective Antibacterial Activity
Modular and Adaptable Tumor Niche Prepared from Visible Light Initiated Thiol-Norbornene Photopolymerization
Yingke_WuLight Initiated Thiol-Norbornene
Anisotropic Materials for Skeletal-Muscle-Tissue Engineering
Yingke_WuAnisotropic Materials for Skeletal-Muscle-Tissue Engineering
Repair of damaged skeletal-muscle tissue is limited by the regenerative capacity of the native tissue. Current clinical approaches are not optimal for the treatment of large volumetric skeletal-muscle loss. As an alternative, tissue engineering represents a promising approach for the functional restoration of damaged muscle tissue. A typical tissue-engineering process involves the design and fabrication of a scaffold that closely mimics the native skeletal-muscle extracellular matrix (ECM), allowing organization of cells into a physiologically relevant 3D architecture. In particular, anisotropic materials that mimic the morphology of the native skeletal-muscle ECM, can be fabricated using various biocompatible materials to guide cell alignment, elongation, proliferation, and differentiation into myotubes. Here, an overview of fundamental concepts associated with muscle-tissue engineering and the current status of muscle-tissue-engineering approaches is provided. Recent advances in the development of anisotropic scaffolds with micro- or nanoscale features are reviewed, and how scaffold topographical, mechanical, and biochemical cues correlate to observed cellular function and phenotype development is examined. Finally, some recent developments in both the design and utility of anisotropic materials in skeletal-muscle-tissue engineering are highlighted, along with their potential impact on future research and clinical applications.
Muscle-tissue-engineering approaches are reviewed, focusing on anisotropic matrices, including micropatternered substrates, and aligned microporous and aligned fibrous scaffolds. Challenges associated with engineering aligned matrices are highlighted and correlation of scaffold topographical, mechanical, and biochemical cues to cellular function and myogenic phenotype development is discussed.
DNA-Mediated Self-Organization of Polymeric Nanocompartments Leads to Interconnected Artificial Organelles
Yingke_WuDNA桥接
Photoswitching of glass transition temperatures of azobenzene-containing polymers induces reversible solid-to-liquid transitions
Yingke_Wupolymer solid-to-liquid transitions
Nature Chemistry. doi:10.1038/nchem.2625
Authors: Hongwei Zhou, Changguo Xue, Philipp Weis, Yasuhito Suzuki, Shilin Huang, Kaloian Koynov, Günter K. Auernhammer, Rüdiger Berger, Hans-Jürgen Butt & Si Wu
Reversibly inducing solid-to-liquid transitions of polymers at room temperature represents a challenge for enhanced processability and applications of polymers. Now, three azopolymers have been shown to exhibit photoswitchable glass transition temperatures, resulting in reversible, solid-to-liquid transitions. Light exposure can heal cracks in hard azopolymers, reduce surface roughness of azopolymer films and control azopolymer adhesion.
Biofilms: Hydrophobic Properties of Biofilm-Enriched Hybrid Mortar (Adv. Mater. 37/2016)
Yingke_WuBiofilms
O. Lieleg and co-workers present a mortar hybrid material on page 8138, in which the biomineralization process is stimulated by adding a biological component, i.e., a bacterial biofilm, to standard mortar. This hybrid mortar, illustrated on the left side of the image, shows increased roughness and hydrophobicity compared to the standard mortar, which is depicted on the right side.
Side Chain Degradable Cationic–Amphiphilic Polymers with Tunable Hydrophobicity Show in Vivo Activity
Yingke_Wu烷基链长度对抗菌影响
Seawater-Assisted Self-Healing of Catechol Polymers via Hydrogen Bonding and Coordination Interactions
Yingke_WuSeawater-Assisted Self-Healing
High-Strength and High-Toughness Double-Cross-Linked Cellulose Hydrogels: A New Strategy Using Sequential Chemical and Physical Cross-Linking
Yingke_Wu水凝胶
Polysaccharide-based hydrogels have multiple advantages because of their inherent biocompatibility, biodegradability, and non-toxicic properties. The feasibility of using polysaccharide-based hydrogels could be improved if they could simultaneously fulfill the mechanical property and cell compatibility requirements for practical applications. Herein, the construction of double-cross-linked (DC) cellulose hydrogels is described using sequential chemical and physical cross-linking, resulting in DC cellulose hydrogels that are mechanically superior to single-cross-linked cellulose hydrogels. The formation and spatial distribution of chemically cross-linked domains and physically cross-linked domains within the DC cellulose hydrogels are demonstrated. The molar ratio of epichlorohydrin to anhydroglucose units of cellulose and the concentration of the aqueous ethanol solution are two critical parameters for obtaining mechanically strong and tough DC cellulose hydrogels. The mechanical properties of the DC cellulose hydrogels under loading-unloading cycles are described using compression and tension models. The possible toughening mechanism of double-cross-linking is discussed.
Double-cross-linked (DC) cellulose hydrogels are fabricated by a sequential chemical and physical cross-linking strategy. The irreversible covalent cross-linkings, cellulose II crystallite hydrates, together with the chain entanglements and strong hydrogen bonding interactions between cellulose chains endow the DC cellulose hydrogels with high strength, high toughness, and good recoverability.
Responsive Biomaterials: Advances in Materials Based on Shape-Memory Polymers
Yingke_Wu形状记忆
Shape-memory polymers (SMPs) are morphologically responsive materials with potential for a variety of biomedical applications, particularly as devices for minimally invasive surgery and the delivery of therapeutics and cells for tissue engineering. A brief introduction to SMPs is followed by a discussion of the current progress toward the development of SMP-based biomaterials for clinically relevant biomedical applications.
Stimuli-responsive shape-memory polymer-based materials have great potential for a variety of biomedical applications. Their development toward use as functional biomedical devices for drug delivery, minimally invasive surgery and tissue engineering are discussed, particularly with a view to their progress toward clinical relevance.
Extremely Stretchable and Fast Self-Healing Hydrogels
Yingke_Wu快速自修复水凝胶
Surface-Adaptive, Antimicrobially Loaded, Micellar Nanocarriers with Enhanced Penetration and Killing Efficiency in Staphylococcal Biofilms
Yingke_Wu抗生物膜
Shape-Dependent Activation of Cytokine Secretion by Polymer Capsules in Human Monocyte-Derived Macrophages
Yingke_Wu形状对巨噬细胞影响
Dense Poly(ethylene glycol) Brushes Reduce Adsorption and Stabilize the Unfolded Conformation of Fibronectin
Yingke_WuPEG接枝密度对蛋白吸附及构象影响
Ionomers for Tunable Softening of Thermoplastic Polyurethane
Yingke_Wu聚氨酯
Dopamine/Silica Nanoparticle Assembled, Microscale Porous Structure for Versatile Superamphiphobic Coating
Yingke_WuDOPA表面接枝
How Photoisomerization Drives Peptide Folding and Unfolding: Insights from QM/MM and MM Dynamics Simulations
Yingke_Wu光控蛋白二级结构
Abstract
Photoswitchable azobenzene cross-linkers can control the folding and unfolding of peptides by photoisomerization and can thus regulate peptide affinities and enzyme activities. Using quantum mechanics/molecular mechanics (QM/MM) methods and classical MM force fields, we report the first molecular dynamics simulations of the photoinduced folding and unfolding processes in the azobenzene cross-linked FK-11 peptide. We find that the interactions between the peptide and the azobenzene cross-linker are crucial for controlling the evolution of the secondary structure of the peptide and responsible for accelerating the folding and unfolding events. They also modify the photoisomerization mechanism of the azobenzene cross-linker compared with the situation in vacuo or in solution.
Using quantum mechanics/molecular mechanics (QM/MM) and classical MM dynamics methods the photoinduced folding and unfolding of an azobenzene cross-linked peptide was simulated. The interaction between the peptide and the cross-linker plays a key role not only in regulating the photoinduced evolution of the secondary structure of the peptide, but also in tuning the photoisomerization mechanism of the azobenzene cross-linker.
Phosphorylcholine-Based Zwitterionic Biocompatible Thermogel
Yingke_Wu磷脂水凝胶
Injectable Self-Healing Glucose-Responsive Hydrogels with pH-Regulated Mechanical Properties
Yingke_WuPH响应水凝胶
Dynamically restructuring pH-responsive hydrogels are synthesized, employing dynamic covalent chemistry between phenylboronic acid and cis-diol modified poly(ethylene glycol) macromonomers. These gels display shear-thinning behavior, followed by a rapid structural recovery (self-healing). Size-dependent in vitro controlled and glucose-responsive release of proteins from the hydrogel network, as well as the biocompatibility of the gels, are evaluated both in vitro and in vivo.
Modulation of the gene expression of annulus fibrosus-derived stem cells using poly(ether carbonate urethane)urea scaffolds of tunable elasticity
Yingke_Wu聚氨酯弹性对细胞表型影响
Source:Acta Biomaterialia
Author(s): Caihong Zhu, Jun Li, Chen Liu, Pinghui Zhou, Huilin Yang, Bin Li
Annulus fibrosus (AF) injuries commonly lead to substantial deterioration of the intervertebral disc (IVD). While tissue engineering has recently evolved into a promising approach for AF regeneration, it remains challenging due to the cellular, biochemical, and mechanical heterogeneity of AF tissue. In this study, we explored the use of AF-derived stem cells (AFSCs) to achieve diversified differentiation of cells for AF tissue engineering. Since the differentiation of stem cells relies significantly on the elasticity of the substrate, we synthesized a series of biodegradable poly(ether carbonate urethane)urea (PECUU) materials whose elasticity approximated that of native AF tissue. When AFSCs were cultured on electrospun PECUU fibrous scaffolds, the gene expression of collagen-I in the cells increased with the elasticity of scaffold material, whereas the expression of collagen-II and aggrecan genes showed an opposite trend. At the protein level, the content of collagen-I gradually increased with substrate elasticity, while collagen-II and GAG contents decreased. In addition, the cell traction forces (CTFs) of AFSCs gradually decreased with scaffold elasticity. Such substrate elasticity-dependent changes of AFSCs were similar to the gradual transition in the genetic, biochemical, and biomechanical characteristics of cells from inner to outer regions of native AF tissue. Together, findings from this study indicate that AFSCs, depending on the substrate elasticity, have strong tendencies to differentiate into various types of AF-like cells, thereby providing a solid foundation for the tissue engineering applications of AFSCs. Statement of significance Repairing the annulus fibrosus (AF) of intervertebral disc (IVD) is critical for the treatment of disc degeneration disease, but remains challenging due to the significant heterogeneity of AF tissue. Previously, we have identified rabbit AF-derived stem cells (AFSCs), which are AF tissue-specific and hold promise for AF regeneration. In this study, we synthesized a series of poly(ether carbonate urethane)ureas of various elasticity (or stiffness) and explored the potential of induced differentiation of AFSCs using electrospun PECUU scaffolds. This work has, for the first time, found that AFSCs are able to present different gene expression patterns simply as a result of the elasticity of scaffold material. Therefore, our findings will help supplement current knowledge of AF tissue regeneration and may benefit a diversified readership from scientific, engineering, and clinical settings whose work involves the biology and tissue engineering of IVD.
Graphical abstract
Insoluble elastin reduces collagen scaffold stiffness, improves viscoelastic properties, and induces a contractile phenotype in smooth muscle cells
Source:Biomaterials, Volume 73
Author(s): Alan J. Ryan, Fergal J. O'Brien
Biomaterials with the capacity to innately guide cell behaviour while also displaying suitable mechanical properties remain a challenge in tissue engineering. Our approach to this has been to utilise insoluble elastin in combination with collagen as the basis of a biomimetic scaffold for cardiovascular tissue engineering. Elastin was found to markedly alter the mechanical and biological response of these collagen-based scaffolds. Specifically, during extensive mechanical assessment elastin was found to reduce the specific tensile and compressive moduli of the scaffolds in a concentration dependant manner while having minimal effect on scaffold microarchitecture with both scaffold porosity and pore size still within the ideal ranges for tissue engineering applications. However, the viscoelastic properties were significantly improved with elastin addition with a 3.5-fold decrease in induced creep strain, a 6-fold increase in cyclical strain recovery, and with a four-parameter viscoelastic model confirming the ability of elastin to confer resistance to long term deformation/creep. Furthermore, elastin was found to result in the modulation of SMC phenotype towards a contractile state which was determined via reduced proliferation and significantly enhanced expression of early (α-SMA), mid (calponin), and late stage (SM-MHC) contractile proteins. This allows the ability to utilise extracellular matrix proteins alone to modulate SMC phenotype without any exogenous factors added. Taken together, the ability of elastin to alter the mechanical and biological response of collagen scaffolds has led to the development of a biomimetic biomaterial highly suitable for cardiovascular tissue engineering.
A macrophage/fibroblast co-culture system using a cell migration chamber to study inflammatory effects of biomaterials
Yingke_Wu巨噬细胞与L929共培养
Source:Acta Biomaterialia, Volume 26
Author(s): Guoying Zhou, Harald Loppnow, Thomas Groth
Chronic inflammatory reactions hamper the use of biomaterials after implantation. Thus, the aim of the study was to develop a novel predictive in vitro macrophage/fibroblast co-culture model based on cell migration chambers that allows a timely and locally controlled interaction of both cell types to study the inflammatory responses of biomaterials in vitro. Here, self-assembled monolayers (SAMs) with different wettability and charge properties were used as model biomaterials on which co-cultures were established by use of fence chambers having internal and external compartments. This allowed establishing separated and mixed co-cultures of both cell types before and after removal of the chamber, respectively. The key advantages of this novel co-culture model included not only to establish a timely-resolved study of cytokine release, but also the ability to assess individual macrophage migration in both macrophage mono-cultures and co-cultures. All inflammatory reactions in terms of macrophage adhesion, macrophage migration, foreign body giant cell (FBGC) formation, β1 integrin expression and pro-inflammatory cytokine production were found strongly surface property dependent. The results show that the hydrophobic CH3 surface caused the strongest inflammatory reactions, whereas the hydrophilic/anionic COOH surface caused the least inflammatory response, indicating low and high biocompatibility of the surfaces, respectively. Most importantly, we found that both macrophage motility and directional movement were increased in the presence of fibroblasts in co-cultures compared with macrophage mono-cultures. Overall, the novel co-culture system provides access to a range of parameters for studying inflammatory reactions and reveals how material surface properties affect the inflammatory responses.