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1.
Dark‐Field‐Based Observation of Single‐Nanoparticle Dynamics on a Supported Lipid Bilayer for In Situ Analysis of Interacting Molecules and Nanoparticles 下载免费PDF全文
Observation of single plasmonic nanoparticles in reconstituted biological systems allows us to obtain snapshots of dynamic processes between molecules and nanoparticles with unprecedented spatiotemporal resolution and single‐molecule/single‐particle‐level data acquisition. This Concept is intended to introduce nanoparticle‐tethered supported lipid bilayer platforms that allow for the dynamic confinement of nanoparticles on a two‐dimensional fluidic surface. The dark‐field‐based long‐term, stable, real‐time observation of freely diffusing plasmonic nanoparticles on a lipid bilayer enables one to extract a broad range of information about interparticle and molecular interactions throughout the entire reaction period. Herein, we highlight important developments in this context to provide ideas on how molecular interactions can be interpreted by monitoring dynamic behaviors and optical signals of laterally mobile nanoparticles. 相似文献
2.
Solution Polymeric Optical Temperature Sensors with Long‐Term Memory Function Powered by Supramolecular Chemistry 下载免费PDF全文
Victor R. de la Rosa Prof. Richard Hoogenboom 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(3):1302-1311
A poly[(2‐ethyl‐2‐oxazoline)‐ran‐(2‐nonyl‐2‐oxazoline)] copolymer in combination with hydroxypropylated cyclodextrins has been demonstrated to lead to a supramolecular self‐assembly process that results in the formation of kinetically trapped thermoresponsive nanoparticles. Selection of the cyclodextrin type provides control over the nanoparticle phase‐transition thermodynamics, thus affording optical temperature sensors with an unprecedented, long‐term thermal memory function, which is reversible or irreversible. This research also sheds light onto kinetic and dynamic supramolecular assemblies, thus providing important insight because similar supramolecular processes are at the foundation of living matter. 相似文献
3.
A Simple and Fast Aqueous‐Phase Synthesis of Ultra‐Highly Concentrated Silver Nanoparticles and Their Catalytic Properties 下载免费PDF全文
Aasim Shahzad Prof. Dr. Minsub Chung Prof. Dr. Taekyung Yu Prof. Dr. Woo‐Sik Kim 《化学:亚洲杂志》2015,10(11):2512-2517
A simple and fast synthetic route to ultra‐highly concentrated silver nanoparticles with long‐term stability by reducing AgNO3 with ascorbic acid in the presence of polyethyleneimine (PEI) as a stabilizer in an aqueous phase is reported. The concentration of silver precursor was as high as 2000 mm (200 g of Ag nanoparticle per liter of water) and the reaction time was less than 10 min. The resulting silver nanoparticles show long‐term stability after two months of storage at room temperature without any signs of particle aggregation or precipitation in an aqueous phase. The successful ligand exchange of PEI‐stabilized silver nanoparticles to polyethylene glycol (PEG) and polyvinylpyrrolidone (PVP) without particle aggregation is also demonstrated. In addition, the catalytic activities of silver nanoparticles stabilized by various stabilizers prepared by the ligand exchange method was investigated. The PEI‐stabilized silver nanoparticles exhibited a higher stability than those of PEG‐ and PVP‐stabilized silver nanoparticles in the diffusion‐controlled catalytic reduction of 4‐nitrophenol to 4‐aminophenol by NaBH4. 相似文献
4.
Polyrotaxane‐Mediated Self‐Assembly of Gold Nanospheres into Fully Reversible Supercrystals 下载免费PDF全文
Joao Paulo Coelho Guillermo González‐Rubio Annette Delices Prof. José Osío Barcina Cástor Salgado Dr. David Ávila Dr. Ovidio Peña‐Rodríguez Prof. Gloria Tardajos Dr. Andrés Guerrero‐Martínez 《Angewandte Chemie (International ed. in English)》2014,53(47):12751-12755
The use of a thiol‐functionalized nonionic surfactant to stabilize spherical gold nanoparticles in water induces the spontaneous formation of polyrotaxanes at the nanoparticle surface in the presence of the macrocycle α‐cyclodextrin. Whereas using an excess of surfactant an amorphous gold nanocomposite is obtained, under controlled drying conditions the self‐assembly between the surface supramolecules provides large and homogenous supercrystals with hexagonal close packing of nanoparticles. Once formed, the self‐assembled supercrystals can be fully redispersed in water. The reversibility of the crystallization process may offer an excellent reusable material to prepare gold nanoparticle inks and optical sensors with the potential to be recovered after use. 相似文献
5.
Novel nanocomposites consisting of genipin cross‐linked chitosan (GC), poly(ethylene glycol) (PEG), and silver nanoparticles were prepared for such biomedical applications as the wound‐healing materials. Various amounts of silver nanoparticles were dispersed in the GC/PEG hydrogel matrix without severe aggregation. The effects of composition and silver nanoparticles on the physico‐chemical properties of samples were evaluated by infrared analysis, contact angle measurements, and swelling tests. The GC/PEG/Ag nanocomposite showed a pH‐sensitive swelling behavior. The surface hydrophilicity of GC/PEG/Ag nanocomposites was improved with the increase of silver nanoparticle content. L929 cell attachment was improved in the presence of silver nanoparticles. The antimicrobial function was assessed for the GC/PEG/Ag nanocomposites containing the silver content over 100 ppm. The silver nanoparticles had the dual functions of reinforcing structural stability and enhancing antimicrobial activity of GC/PEG/Ag nanocomposites. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
6.
The Construction and Transition of Supramolecular Hydrogels Induced by Cyclodextrin Inclusion 下载免费PDF全文
Soft hydrogel nano‐ and micro‐structures have great potential applications in the field of tissue engineering and chemical sensors. In this paper, a supramolecular hydrogel was constructed by combining a triblock copolymer poly(ethylene oxide)100‐(propyleneoxide)70‐(ethyleneoxide)100 (PEO100‐PPO70‐PEO100 ) (Pluronic F127), mono‐6‐thio‐β‐cyclodextrins (SH‐β‐CDs), and silver nanoparticles. Here, SH‐β‐CDs couple to the silver nanoparticles via thio groups and include PPO blocks of F127 using the hydrophobic cavity to form pseudo‐polyrotaxanes. Moreover, the hydrogel can be transformed to a homogenous solution by the addition of hydrochloride powder. These results are important for research related to the construction of soft hydrogel materials and control their mechanical properties. 相似文献
7.
The intense colors of noble metal nanoparticles have inspired artists and fascinated scientists for hundreds of years. In this review, we describe refractive index sensing platforms based on the tunability of the localized surface plasmon resonance (LSPR) of arrays of silver nanoparticles and of single nanoparticles. Specifically, the color associated with single nanoparticles and surface-confined nanoparticle arrays will be shown to be tunable and useful as platforms for chemical and biological sensing. Finally, the LSPR nanosensor will be compared to traditional, flat surface, propagating surface plasmon resonance sensors. 相似文献
8.
《Macromolecular bioscience》2017,17(9)
A hybrid hydrogel composed of solid lipid nanoparticles (LNPs) entrapped within chemically cross‐linked carboxymethylcellulose (CMC) is developed to achieve localized and sustained release of lipophilic drugs. The analysis of LNP stability as well as the hydrogel swelling and mechanical properties confirm the successful incorporation of particles up to a concentration of 50% w/wCMC. The initial LNP release rate can be prolonged by increasing the particle diameter from 50 to 120 nm, while the amount of long‐term release can be adjusted by tailoring the particle surface charge or the cross‐linking density of the polymer. After 30 d, 58% of 50 nm diameter negatively charged LNPs escape from the matrix while only 17% of positively charged nanoparticles are released from materials with intermediate cross‐linking density. A mathematical diffusion model based on Fick's second law is efficient to predict the diffusion of the particles from the hydrogels. 相似文献
9.
Significant efforts have been invested in finding a delivery system that can encapsulate and deliver therapeutics. Core–shell polymer‐lipid hybrid nanoparticles have been studied as a promising platform because of their mechanical stability, narrow size distribution, biocompatibility, and ability to co‐deliver diverse drugs. Here, novel core–shell nanoparticles based on a poly(lactic‐co‐glycolic acid) (PLGA) core and multilamellar lipid shell are designed, where the lipid bilayers are crosslinked between the two adjacent bilayers (PLGA‐ICMVs). The cross‐platform performance of the nanoparticles to other polymer‐lipid hybrid platforms is examined, including physicochemical characteristics, ability to encapsulate a variety of therapeutics, biocompatibility, and functionality as a vaccine delivery platform. Differential abilities of nanoparticle systems to encapsulate distinct pharmaceutics are observed, which suggest careful consideration of the platform chosen depending on the therapeutic agent and desired function. The novel PLGA‐ICMV platform herein demonstrates great potential in stably encapsulating water‐soluble agents and therefore is an attractive platform for therapeutic delivery. 相似文献
10.
Injectable hydrogels for nonsteroidal anti‐inflammatory drugs’ (NSAIDs) delivery to minimize the side effects of NSAIDs and achieve long‐term sustained release at the targeted site of synovial joint are attractive for osteoarthritis therapy, but how to improve its mechanical strength remains a challenge. In this work, a kind of 1D natural clay mineral material, attapulgite (ATP), is introduced to a classical cyclodextrin pseudopolyrotaxane (PPR) system to form a reinforced supramolecular hydrogel for sustained release of diclofenac sodium (DS) due to its rigid, rod‐like morphology, and unique structure, which has great potential in tissue regeneration, repair, and engineering. Investigation on the interior morphology and rheological property of the obtained hydrogel points out that the ATP distributed in PPR hydrogel plays a role similar to the “reinforcement in concrete” and exhibits a positive effect on improving the mechanical properties of PPR hydrogel by regulating their interior morphology from a randomly distributed style to the well‐ordered porous frame structure. The hybrid hydrogels demonstrate good shear‐thinning and thixotropic properties, excellent biocompability, and sustained release behavior both in vitro and in vivo. Furthermore, preliminary in vivo treatment in an acute inflammatory rat model reveals that the ATP hybrid hydrogels present sustained anti‐inflammatory effect. 相似文献
11.
《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2017,129(4):986-991
The use of biomacromolecular therapeutics has revolutionized disease treatment, but frequent injections are required owing to their short half‐life in vivo. Thus there is a need for a drug delivery system that acts as a reservoir and releases the drug remotely “on demand”. Here we demonstrate a simple light‐triggered local drug delivery system through photo‐thermal interactions of polymer‐coated gold nanoparticles (AuNPs) inside an agarose hydrogel as therapeutic depot. Localized temperature increase induced by the visible light exposure caused reversible softening of the hydrogel matrix to release the pre‐loaded therapeutics. The release profile can be adjusted by AuNPs and agarose concentrations, light intensity and exposure time. Importantly, the biological activity of the released bevacizumab was highly retained. In this study we demonstrate the potential application of this facile AuNPs/hydrogel system for ocular therapeutics delivery through its versatility to release multiple biologics, compatibility to ocular cells and spatiotemporal control using visible light. 相似文献
12.
Kell AJ Somaskandan K Stewart G Bergeron MG Simard B 《Langmuir : the ACS journal of surfaces and colloids》2008,24(7):3493-3502
There is currently significant interest in the miniaturization of disease detection platforms. As detection platforms decrease in size there is a need for the development of sample preparation protocols by which cells or biomarkers of interest can be concentrated from large volumes down to volumes more amenable to analysis within microfluidic devices. To address this issue, we present a series of magnetic confinement assays for polystyrene (PS) beads mediated through their covalent modification with a series of superparamagnetic nanoparticles, where the PS beads have many properties similar to bacteria, but are not pathogenic. The magnetic confinement of the PS beads is investigated as a function of (1) the overall nanoparticle size, (2) the loading of superparamagnetic content within the nanoparticle matrix, and (3) the viscosity and volume of the dispersion medium. We demonstrate that the time required for the magnetic capture of the PS beads by the superparamagnetic nanoparticles (1) decreases as the loading of superparamagnetic material into the nanoparticles increases and (2) increases as the viscosity and volume of the dispersion medium are increased. However, limitations in the magnetic confinement efficiency for the PS beads labeled with nanoparticles comprised of low loadings of superparamagnetic material can be overcome through the use of magnetic columns. These magnetic columns provide a practical and fast mode of sample preparation that should facilitate the magnetic concentration of cells and biomarkers from large volumes to volumes more amenable to incorporation into a microfluidic-based analysis system, where they can be analyzed/detected. 相似文献
13.
A Novel Non‐Enzymatic Glucose Sensor Based on Cobalt Nanoparticles Implantation‐Modified Indium Tin Oxide Electrode 下载免费PDF全文
A new type of cobalt nanoparticles modified indium tin oxide electrode (CoNPs/ITO) was fabricated using ion implantation technique. This method is low‐cost, facile and environmentally friendly without the use of any other chemicals. Electrochemical oxidation of glucose with this sensor was examined by cyclic voltammetry (CV) and chronoamperometry in alkaline aqueous solutions. The proposed sensor exhibited prominent electrocatalytic activity toward the oxidation of glucose with a low limit of detection of 0.25 µM. Furthermore, the fabricated electrode showed excellent selectivity, good reproducibility and long‐term stability. Thus CoNPs/ITO electrode is a promising candidate in the development of non‐enzymatic glucose sensors. 相似文献
14.
Inhibition of Inflammation‐Associated Thrombosis with ROS‐Responsive Heparin‐DOCA/PVAX Nanoparticles
Zehong Xiang Yanming Wang Zhifang Ma Zhirong Xin Runhai Chen Qiang Shi Shing‐Chung Wong Jinghua Yin 《Macromolecular bioscience》2019,19(8)
Inflammation‐associated thrombosis is a non‐negligible source of mortalities and morbidities worldwide. To manipulate inflammation‐associated coagulation, nanoparticles that contain anti‐inflammatory polymer (copolyoxalate containing vanillyl alcohol, PVAX) and anti‐thrombotic heparin derivative deoxycholic acid (Hep‐DOCA) are prepared. The strategy takes advantage of the reducted side effects of heparin through heparin conjugation, achievement of long‐term anti‐inflammation by inflammation‐trigged release of anti‐inflammatory agents, and formation of PVAX/heparin‐DOCA nanoparticles by co‐self‐assembly. It is demonstrated that the Hep‐DOCA conjugate and PVAX are synthesized successfully; PVAX and Hep‐DOCA nanodrugs (HDP) are obtained by co‐assembly; the HDP nanoparticles effectively reduce the inflammation and coagulation without inducing lethal bleeding both in vivo and in vitro. The method provided here is versatile and effective, which paves new way to develop nanodrugs to treat inflammation‐associated thrombosis safely. 相似文献
15.
Eunji Jang Saemi Park Sangphil Park Yeol Lee Dae‐Nyun Kim Bumsang Kim Won‐Gun Koh 《先进技术聚合物》2010,21(7):476-482
In this study, we immobilized enzymes by combining covalent surface immobilization and hydrogel entrapment. A model enzyme, glucose oxidase (GOX), was first covalently immobilized on the surface of silica nanoparticles (SNPs) via 3‐aminopropyltriethoxysilane (APTES), and the resultant SNP‐immobilized enzyme was physically entrapped within photopolymerized hydrogels prepared from two different molecular weights (MWs) (575 and 8000 Da) of poly(ethylene glycol)(PEG). The hydrogel entrapment resulted in a decrease in reaction rate and an increase in apparent Km of SNP‐immobilized GOX, but these negative effects could be minimized by using hydrogel with a higher MW PEG, which provides higher water content and larger mesh size. The catalytic rate of the PEG 8000 hydrogel was about ten times faster than that of the PEG 575 hydrogel because of enhanced mass transfer. Long‐term stability test demonstrated that SNP‐immobilized GOX entrapped within hydrogel maintained more than 60% of its initial activity after a week, whereas non‐entrapped SNP‐immobilized GOX and entrapped GOX without SNP immobilization maintained less than 20% of their initial activity. Incorporation of SNPs into hydrogel enhanced the mechanical strength of the hydrogel six‐fold relative to bare hydrogels. Finally, a hydrogel microarray entrapping SNP‐immobilized GOX was fabricated using photolithography and successfully used for quantitative glucose detection. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
16.
《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2017,129(11):2935-2938
Macrocyclic chelators have been widely employed in the realm of nanoparticle‐based positron emission tomography (PET) imaging, whereas its accuracy remains questionable. Here, we found that 64Cu can be intrinsically labeled onto nanographene based on interactions between Cu and the π electrons of graphene without the need of chelator conjugation, providing a promising alternative radiolabeling approach that maintains the native in vivo pharmacokinetics of the nanoparticles. Due to abundant π bonds, reduced graphene oxide (RGO) exhibited significantly higher labeling efficiency in comparison with graphene oxide (GO) and exhibited excellent radiostability in vivo. More importantly, nonspecific attachment of 1,4,7‐triazacyclononane‐1,4,7‐triacetic acid (NOTA) on nanographene was observed, which revealed that chelator‐mediated nanoparticle‐based PET imaging has its inherent drawbacks and can possibly lead to erroneous imaging results in vivo. 相似文献
17.
A hybrid supramolecular polymeric hydrogel is conveniently constructed via host–guest interaction of a host cyclodextrin polymer (poly‐CD) with a guest α‐bromonaphthalene polymer (poly‐BrNp) and mixing with 6‐thio‐β‐cyclodextrin (β‐SH‐CD) modified gold nanoparticles (GPCDs) in aqueous solution. According to the dynamic oscillatory data, the hydrogel exhibits markedly enhanced stiffness compared with the GPCD‐free one (both G′ and G“ values are almost twice as high as those of the original GPCD‐free hydrogel) due to the introduction of the inorganic gold nanoparticles. This hybrid supramolecular polymeric hydrogel has a rapid and excellent self‐healing property (only about 1 min, and the G′ and G” of the self‐healed hydrogel almost turned back to their original levels after 1 hour) in air (without adding any solvent or additive). 相似文献
18.
Chen Qian Gang Wu Di Jiang Xiaona Zhao Hai‐Bo Chen Yunze Yang Xian‐Wei Liu 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(13):4261-4264
The development of optical imaging techniques has led to significant advancements in single‐nanoparticle tracking and analysis, but these techniques are incapable of label‐free selective nanoparticle recognition. A label‐free plasmonic imaging technology that is able to identify different kinds of nanoparticles in water is now presented. It quantifies the plasmonic interferometric scattering patterns of nanoparticles and establishes relationships among the refractive index, particle size, and pattern both numerically and experimentally. Using this approach, metallic and metallic oxide particles with different radii were distinguished without any calibration. The ability to optically identify and size different kinds of nanoparticles can provide a promising platform for investigating nanoparticles in complex environments to facilitate nanoscience studies, such as single‐nanoparticle catalysis and nanoparticle‐based drug delivery. 相似文献
19.
Sachin Kinge Dr. Mercedes Crego‐Calama Dr. David N. Reinhoudt Prof. Dr. 《Chemphyschem》2008,9(1):20-42
Nanoparticles are the focus of much attention due to their astonishing properties and numerous possibilities for applications in nanotechnology. For realising versatile functions, assembly of nanoparticles in regular patterns on surfaces and at interfaces is required. Assembling nanoparticles generates new nanostructures, which have unforeseen collective, intrinsic physical properties. These properties can be exploited for multipurpose applications in nanoelectronics, spintronics, sensors, etc. This review surveys different techniques, currently employed and being developed, for assembling nanoparticles in to ordered nanostructures. In this endeavour, the principles and methods involved in the development of assemblies are discussed. Subsequently, different possibilities of nanoparticle‐based nanostructures, obtained in multi‐dimensions, are presented. 相似文献