共查询到20条相似文献，搜索用时 0 毫秒
1.
Catherine A. Kelly Andrew Naylor Lisbeth Illum Kevin M. Shakesheff Steven M. Howdle 《Advanced functional materials》2012,22(8):1684-1691
The unique combination of the gas like viscosity and liquid like density of supercritical CO2 (scCO2) is exploited to blend poly(D,L‐lactic acid) (PDLLA) and poly(ethylene glycol) (PEG) at near ambient temperatures. This novel process lowers the polymer blend viscosity and also permits incorporation of thermally and solvent labile protein based drugs. A series of blends are prepared with agitation in scCO2. Differential scanning calorimetry (DSC) data shows that miscible blends can be produced at moderate temperatures. A surprising region of miscibility is revealed between 8 and 25%w/w PEG. The properties of this miscible region are probed with high pressure parallel plate rheological studies, showing that the viscosity in scCO2 is directly related to the miscibility. Using the particles from gas saturated solutions (PGSS) method, microparticles of these PDLLA/PEG blends are produced using scCO2 and it is determined that the yields obtained are proportional to the miscibility of the polymers. Thus scCO2 provides a unique route to low temperature, solvent free processing that accesses a window of miscibility that has not previously been observed. Finally, DSC analyses of these sprayed microparticles confirm the presence of the same high miscibility region observed in the bulk samples prepared under supercritical conditions. 相似文献
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High‐performance adhesives require mechanical properties tuned to demands of the surroundings. A mismatch in stiffness between substrate and adhesive leads to stress concentrations and fracture when the bonding is subjected to mechanical load. Balancing material strength versus ductility, as well as considering the relationship between adhesive modulus and substrate modulus, creates stronger joints. However, a detailed understanding of how these properties interplay is lacking. Here, a biomimetic terpolymer is altered systematically to identify regions of optimal bonding. Mechanical properties of these terpolymers are tailored by controlling the amount of a methyl methacrylate stiff monomer versus a similar monomer containing flexible poly(ethylene glycol) chains. Dopamine methacrylamide, the cross‐linking monomer, is a catechol moiety analogous to 3,4‐dihydroxyphenylalanine, a key component in the adhesive proteins of marine mussels. Bulk adhesion of this family of terpolymers is tested on metal and plastic substrates. Incorporating higher amounts of poly(ethylene glycol) into the terpolymer introduces flexibility and ductility. By taking a systematic approach to polymer design, the region in which material strength and ductility are balanced in relation to the substrate modulus is found, thereby yielding the most robust joints. 相似文献
3.
Yifeng Sheng Xiaoqing Ming Chengjiang Lin Chang Yang Xiwei Guo Xiaozheng Duan He Zhu Qi Zhang 《Advanced functional materials》2024,34(37):2401999
Stiffness-variable polymers have found their enormous potential in practical applications that require automatic adaptation and modulation. However, prevailing materials are often constrained by specific operational triggers, limited mechanical responsiveness, and inadequate universality. In this study, drawing inspiration from the mechanism of non-solvent induced phase separation (NIPS), a novel series of polymers exhibiting reversible water-triggered stiffening is designed and synthesized by covalently incorporating poly(ethylene glycol) (PEG) as a non-solvent mediator onto the hydrophobic poly(meth)acrylates backbones. Owing to the hydrophilicity difference between PEG sidechains and backbones, these polymers display swift and substantial alterations in stiffness, with large-scale and regulable changes (from several-fold to exceeding 200-fold) upon water penetration, resulting from water-induced microphase separation. Meanwhile, the polymers also possess intrinsic dual-responsive shape-memory properties. Due to the excellent commercial availability, versatility, and designability of these polymers, the work provides novel perspectives for the advancement of water-triggered stiffening materials and opens avenues for their prospective applications in various domains. 相似文献
4.
Yang Z Gupta JK Kishimoto K Shoji Y Kato T Abbott NL 《Advanced functional materials》2010,20(13):2098-2106
We report an investigation of nematic LCs formed from miscible mixtures of 4-cyano-4'-pentylbiphenyl (5CB) and 2-(2-[2-{2-(2,3-difluoro-4-{4-(4-trans-pentylcyclohexyl)-phenyl-phenoxy)ethoxy}ethoxy]ethoxy)ethanol (EG4-LC), the latter being a mesogen with a tetra(ethylene glycol) tail. Quantitative characterization of the ordering of this LC mixture at biologically-relevant aqueous interfaces revealed that addition of EG4-LC (1-5% by weight) to 5CB causes a continuous transition in the ordering of the LC from a planar (pure 5CB) to a perpendicular (homeotropic) orientation. The homeotropic ordering is also seen in aqueous dispersions of micrometer-sized droplets of the LC mixture, which exhibit enhanced stability against coalescence. These observations and others, all of which suggest partitioning of the EG4-LC from the bulk of the LC to its aqueous interface, were complemented by measurements of the adsorption of bovine serum albumin (BSA) to the aqueous-LC interface. Whereas adsorption of BSA to the interface of a LC mixture containing 1% wt/wt of EG4-LC triggered an ordering transition, higher concentrations of EG4-LC (>2% wt/wt) prevented this ordering transition, consistent with a decrease in adsorption of BSA. This conclusion is supported by epifluorescence measurements using fluorescently labeled BSA and comparisons to LC interfaces at which EG4-containing lipids are adsorbed. Overall, these results demonstrate a general and facile approach to the design of LCs with interfaces that present biologically relevant chemical functional groups, assume well-defined orientations at aqueous interfaces, and lower non-specific protein adsorption. The bulk of the LC serves as a reservoir of EG4-LC, thus permitting easy preparation of these interfaces and the potential for spontaneous repair of the EG4-decorated interfaces during contact with biological systems. 相似文献
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Since the traditional 2D surface for cell growth has been shown to be increasingly insufficient in contemporary cell biology, more and more research is performed on 3D matrices that can better represent the natural extracellular matrix (ECM) in many aspects. To create such a complex nonuniform 3D matrix, four‐armed polyethylene glycol with azides and (1R,8S,9S)‐bicyclo[6.1.0]non‐4‐yn‐9‐yl groups is functionalized to form the hydrogel basis. Together with these, a matrix metalloproteinase cleavable peptide sequence as a functional motif is also built in to add degradability to the hydrogel. In addition, self‐assembled peptide amphiphile (PA) fibers containing a cellular binding peptide sequence (RGDS) are encapsulated in the hydrogel to mimic the natural fibrous structure of the ECM and to stimulate cell adhesion. Rheology studies confirm that the polymer dissolved in the PA fiber solution forms a stable hydrogel with acceptable mechanical properties (G′ = 3.8 kPa). In addition, it is shown that this hydrogel network is degradable under the action of a metalloproteinase enzyme. Finally, the hybrid hydrogel is used to culture and it is demonstrated that both HeLa cells and human mesenchymal stem cells show adherence, good viability, and a well‐spread shape inside the hybrid hydrogel after 5 days of incubation when all components are present. 相似文献
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Eran Ivanir Yonatan Shachaf Iris Mironi‐Harpaz Daniella Yeheskely‐Hayon Lena Hazanov Shlomit Harpaz‐Segev Tamara Birman Limor Minai Sonia Melino Dvir Yelin Dror Seliktar 《Advanced functional materials》2020,30(18)
The ability to precisely control cell‐loaded material systems is essential for in vitro testing of novel therapeutics poised to advance to clinic. In this report, unique patterns of cell migration are devised into an in vitro gel‐in‐gel model for the purpose of obtaining cell response data to potentially therapeutic chemical agonists. The model consists of co‐cultures in a cell‐loaded microgel invading an acellular “sorting” gel. Material properties including biophysical and chemical compositions of the sorting gel are carefully controlled to guide a desired cell‐specific behavior, leading to massive tumor cell invasion by amoeboid migration mechanisms. Optical transparency enables straightforward and high‐throughput measurements of outgrowth response in the presence of either chemical and photoradiation therapy. Important dosing and drug sensitivity information are obtained with the gel‐in‐gel model using no more than a light microscope, without further need for arduous genomic or proteomic screening of the tissue samples. 相似文献
9.
Yang Li Xinda Li Shiming Zhang Leslie Liu Natalie Hamad Sanyasi Rao Bobbara Damiano Pasini Fabio Cicoira 《Advanced functional materials》2020,30(30)
Self‐healing electronic materials are of primary interest for bioelectronics and sustainable electronics. In this work, autonomic self‐healing of films obtained from mixtures of the conducting polymer poly(3,4‐ethylenedioxythiophene) doped with polystyrene sulfonate (PEDOT:PSS) and polyethylene glycol (PEG) is reported. The presence of PEG in PEDOT:PSS films decreases the elastic modulus and increases the elongation at break, thus leading to a softer material with enhanced self‐healing characteristics. In situ imaging of the cutting/healing process shows that the healing mechanism is likely due to flowing back of the material to the damaged area right after the cutting. 相似文献
10.
Fawzia Bekkara‐Aounallah Ruxandra Gref Mohammad Othman L. Harivardhan Reddy Barbara Pili Vanessa Allain Claudie Bourgaux Hervé Hillaireau Sinda Lepêtre‐Mouelhi Didier Desmaële Julien Nicolas Nafa Chafi Patrick Couvreur 《Advanced functional materials》2008,18(22):3715-3725
This study describes a new simple method to obtain high loading of anticancer or antiviral nucleoside analogues into “stealth” poly(ethylene glycol) (PEG)‐coated nanoassemblies. These nanodevices are obtained by co‐nanoprecipitation in water of (i) squalenoyl prodrugs obtained by the bioconjugation of the natural lipid squalene with either the anticancer drug gemcitabine (Gem‐Sq) or the antiviral drug deoxycytidine (ddC‐Sq) with (ii) a PEG derivative of either cholesterol (Chol‐PEG) or squalene (Sq‐PEG). It was found that both PEG derivatives (Chol‐PEG or Sq‐PEG) were efficiently incorporated in the resulting composite nanoassemblies (CNAs), as shown by radioactivity studies, Zeta potential determination, and size measurements. Optimal compositions were defined for each PEG derivative to ensure the best stability in water and in buffer solutions. X‐ray diffraction and electron microscopy investigations revealed that depending on the structure of the squalenoyl nucleoside analogue used (Gem‐Sq or ddC‐Sq), these nanoassemblies might be toroids or cubosomes. Following PEGylation, the Gem‐Sq nanoassemblies displayed superior in vitro anticancer activity on gemcitabine‐resistant leukemia L1210 10K cells than either their non‐PEGylated counterparts or gemcitabine alone. 相似文献
11.
Y. Zheng F. M. Andreopoulos M. Micic Q. Huo S. M. Pham R. M. Leblanc 《Advanced functional materials》2001,11(1):37-40
A novel eight‐branched poly(ethylene glycol), PEG, macromer having a nitrocinnamate moiety as a pendant group was synthesized and found to form a photoscissile hydrogel upon exposure to 365 nm radiation in the absence of photoinitiators or catalysts. The processes of photocrosslinking and photocleavage were clearly characterized by environmental scanning electron microscopy (ESEM). 相似文献
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Oana Dobre Mariana A. G. Oliva Giuseppe Ciccone Sara Trujillo Aleixandre Rodrigo-Navarro Douglas Cormac Venters Virginia Llopis-Hernandez Massimo Vassalli Cristina Gonzalez-Garcia Matthew J. Dalby Manuel Salmeron-Sanchez 《Advanced functional materials》2021,31(21):2010225
Laminins (LMs) are important structural proteins of the extracellular matrix (ECM). The abundance of every LM isoform is tissue-dependent, suggesting that LM has tissue-specific roles. LM binds growth factors (GFs), which are powerful cytokines widely used in tissue engineering due to their ability to control stem cell differentiation. Currently, the most commonly used ECM mimetic material in vitro is Matrigel, a matrix of undefined composition containing LM and various GFs, but subjected to batch variability and lacking control of physicochemical properties. Inspired by Matrigel, a new and completely defined hydrogel platform based on hybrid LM-poly(ethylene glycol) (PEG) hydrogels with controllable stiffness (1–25 kPa) and degradability is proposed. Different LM isoforms are used to bind and efficiently display GFs (here, bone morphogenetic protein (BMP-2) and beta-nerve growth factor (β-NGF)), enabling their solid-phase presentation at ultralow doses to specifically target a range of tissues. The potential of this platform to trigger stem cell differentiation toward osteogenic lineages and stimulate neural cells growth in 3D, is demonstrated. These hydrogels enable 3D, synthetic, defined composition, and reproducible cell culture microenvironments reflecting the complexity of the native ECM, where GFs in combination with LM isoforms yield the full diversity of cellular processes. 相似文献
13.
Steffen Cosson Stefan A. Kobel Matthias P. Lutolf 《Advanced functional materials》2009,19(21):3411-3419
A versatile strategy to rapidly immobilize complex gradients of virtually any desired protein on soft poly(ethylene glycol) (PEG) hydrogel surfaces that are reminiscent of natural extracellular matrices (ECM) is reported. A microfluidic chip is used to generate steady‐state gradients of biotinylated or Fc‐tagged fusion proteins that are captured and bound to the surface in less than 5 min by NeutrAvidin or ProteinA, displayed on the surface. The selectivity and orthogonality of the binding schemes enables the formation of parallel and orthogonal overlapping gradients of multiple proteins, which is not possible on conventional cell culture substrates. After patterning, the hydrogels are released from the microfluidic chip and used for cell culture. This novel platform is validated by conducting single‐cell migration experiments using time‐lapse microscopy. The orientation of cell migration, as well as the migration rate of primary human fibroblasts, depends on the concentration of an immobilized fibronectin fragment. This technique can be readily applied to other proteins to address a wealth of biological questions with different cell types. 相似文献
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Ashlynn L. Z. Lee Victor W. L. Ng Shujun Gao James L. Hedrick Yi Yan Yang 《Advanced functional materials》2014,24(11):1538-1550
In this study, ‘ABA’‐type triblock copolymers of vitamin E‐functionalized polycarbonate and poly(ethylene glycol) , i.e., VitEm‐PEG‐VitEm, with extremely short hydrophobic block VitEm, are synthesized and employed to form physically cross‐linked injectable hydrogels for local and sustained delivery of Herceptin. The hydrogels are formed at low concentrations (4–8 wt%). By varying polymer composition and concentration, the rheological behavior, porosity, and drug release properties of hydrogels are readily tunable. The in vitro antitumor specificity and efficacy of Herceptin in hydrogel and solution are investigated by MTT assay against normal and human breast cancer cell lines with different HER2 expression levels. The results demonstrate that the Herceptin‐loaded hydrogel is specific towards HER2‐overexpressing cancer cells and cytotoxic action is comparable to that of the Herceptin solution. The biocompatibility and biodegradability of hydrogel are evaluated in mice with subcutaneous injection by histological examination. It is observed that the hydrogel does not evoke a chronic inflammatory response and degrades within 6 weeks post administration. Biodistribution and anti‐tumor efficacy studies performed in BT474 tumor‐bearing mice show that single subcutaneous injection of Herceptin‐loaded hydrogel at a site close to the tumor enhances the retention of the antibody within the tumor. This leads to superior anti‐tumor efficacy as compared to intravenous (i.v.) and subcutaneous (s.c.) delivery of Herceptin in solution. The tumor size shrank by 77% at Day 28. When the hydrogel is injected at a distal location away from the tumor site, anti‐tumor efficacy is similar to that of weekly i.v. injections of Herceptin solution over 4 weeks, with the number of injections reduced from 4 to 1. These findings suggest that this hydrogel has great potential for use in subcutaneous and sustained delivery of antibodies to increase therapeutic efficacy and/or improve patient compliance. 相似文献
16.
Jian Song Jennifer Dailey Hui Li Hyun‐June Jang Pengfei Zhang Jeff Tza‐Huei Wang Allen D. Everett Howard E. Katz 《Advanced functional materials》2017,27(20)
A novel organic field effect transistor (OFET)‐based biosensor is described for label‐free glial fibrillary acidic protein detection. This study reports the first use of an extended solution gate structure where the sensing area and the organic semiconductor are separated, and a reference electrode is not needed. Different molecular weight polyethylene glycols (PEGs) are mixed into the bioreceptor layer to help extend the Debye screening length. The drain current change is significantly increased with the help of higher molecular weight PEGs, as they are known to reduce the dielectric constant. This study also investigates the sensing performance under different gate voltage (V g). The sensitivity increases after the V g is decreased from ?5 to ?2 V because the lower V g is much closer to the OFET threshold voltage and the influence of attached negatively charged proteins becomes more apparent. Finally, the selectivity experiments toward different interferents are performed. The stability and selectivity are promising for clinical applications. 相似文献
17.
Manish Dubey Kazunori Emoto Hironobu Takahashi David G. Castner David W. Grainger 《Advanced functional materials》2009,19(19):3046-3055
Photolithographically prepared surface patterns of two affinity ligands (biotin and chloroalkane) specific for two proteins (streptavidin and HaloTag, respectively) are used to spontaneously form high‐fidelity surface patterns of the two proteins from their mixed solution. High affinity protein‐surface self‐selection onto patterned ligands on surfaces exhibiting low non‐specific adsorption rapidly yields the patterned protein surfaces. Fluorescence images after protein immobilization show high specificity of the target proteins to their respective surface patterned ligands. Time‐of‐flight secondary ion mass spectrometry (ToF‐SIMS) imaging further supports the chemical specificity of streptavidin and HaloTag for their surface patterned ligands from mixed protein solutions. However, ToF‐SIMS did detect some non‐specific adsorption of bovine serum albumin, a masking protein present in excess in the adsorbing solutions, on the patterned surfaces. Protein amino acid composition, surface coverage, density, and orientation are important parameters that determine the relative ToF‐SIMS fragmentation pattern yields. ToF‐SIMS amino acid‐derived ion fragment yields summed to produce surface images can reliably determine which patterned surface regions contain bound proteins, but do not readily discriminate between different co‐planar protein regions. Principal component analysis (PCA) of these ToF‐SIMS data, however, improves discrimination of ions specific to each protein, facilitating surface protein pattern identification and image contrast. 相似文献
18.
Anirudha Singh Jianan Zhan Zhaoyang Ye Jennifer H. Elisseeff 《Advanced functional materials》2013,23(5):575-582
Synthetic polymers are employed to create highly defined microenvironments with controlled biochemical and biophysical properties for cell culture and tissue engineering. Chemical modification is required to input biological or chemical ligands, which often changes the fundamental structural properties of the material. Here, a simple modular biomaterial design strategy is reported that employs functional cyclodextrin nanobeads threaded onto poly(ethylene glycol) (PEG) polymer necklaces to form multifunctional hydrogels. Nanobeads with desired chemical or biological functionalities can be simply threaded onto the PEG chains to form hydrogels, creating an accessible platform for users. The design and synthesis of these multifunctional hydrogels are described, structure‐property relationships are elucidated, and applications ranging from stem cell culture and differentiation to tissue engineering are demonstrated. 相似文献
19.
Hydrogels are being increasingly studied for use in various biomedical applications including drug delivery and tissue engineering. The successful use of a hydrogel in these applications greatly relies on a refined control of the mechanical properties including stiffness, toughness, and the degradation rate. However, it is still challenging to control the hydrogel properties in an independent manner due to the interdependency between hydrogel properties. Here it is hypothesized that a biodegradable polymeric crosslinker would allow for decoupling of the dependency between the properties of various hydrogel materials. This hypothesis is examined using oxidized methacrylic alginate (OMA). The OMA is synthesized by partially oxidizing alginate to generate hydrolytically labile units and conjugating methacrylic groups. It is used to crosslink poly(ethylene glycol) methacrylate and poly(N‐hydroxymethyl acrylamide) to form three‐dimensional hydrogel systems. OMA significantly improves rigidity and toughness of both hydrogels as compared with a small molecule crosslinker, and also controls the degradation rate of hydrogels depending on the oxidation degree, without altering their initial mechanical properties. The protein‐release rate from a hydrogel and subsequent angiogenesis in vivo are thus regulated with the chemical structure of OMA. Overall, the results of this study suggests that the use of OMA as a crosslinker will allow the implantation of a hydrogel in tissue subject to an external mechanical loading with a desired protein‐release profile. The OMA synthesized in this study will be, therefore, highly useful to independently control the mechanical properties and degradation rate of a wide array of hydrogels. 相似文献
20.
Sarah Van Belleghem Leopoldo Torres Marco Santoro Bhushan Mahadik Arley Wolfand Peter Kofinas John P. Fisher 《Advanced functional materials》2020,30(3)
Despite recent advances in clinical procedures, the repair of soft tissue remains a reconstructive challenge. Current technologies such as synthetic implants and dermal flap autografting result in inefficient shape retention and unpredictable aesthetic outcomes. 3D printing, however, can be leveraged to produce superior soft tissue grafts that allow enhanced host integration and volume retention. Here, a novel dual bioink 3D printing strategy is presented that utilizes synthetic and natural materials to create stable, biomimetic soft tissue constructs. A double network ink composed of covalently cross‐linked poly(ethylene) glycol and ionically cross‐linked alginate acts as a physical support network that promotes cell growth and enables long‐term graft shape retention. This is coupled with a cell‐laden, biodegradable gelatin methacrylate bioink in a hybrid printing technique, and the composite scaffolds are evaluated in their mechanical properties, shape retention, and cytotoxicity. Additionally, a new shape analysis technique utilizing CloudCompare software is developed that expands the available toolbox for assessing scaffold aesthetic properties. With this dynamic 3D bioprinting strategy, complex geometries with robust internal structures can be easily modulated by varying the print ratio of nondegradable to sacrificial strands. The versatility of this hybrid printing fabrication platform can inspire the design of future multimaterial regenerative implants. 相似文献