Hybrid polyoxometalates as post-functionalization platforms: from fundamentals to emerging applications

Stimuli-responsive hydrogels have a wide range of potential applications in microfluidics, which has drawn great attention. Double cross-linked hydrogels are very well suited for this application as they offer both stability and the required responsive behavior. Here, we report the integration of poly(N-isopropylacrylamide) (PNiPAAm) hydrogel with a permanent cross-linker (N,N′-methylenebisacrylamide, BIS) and a redox responsive reversible cross-linker (N,N′-bis(acryloyl)cystamine, BAC) into a microfluidic device through photopolymerization. Cleavage and re-formation of disulfide bonds introduced by BAC changed the cross-linking densities of the hydrogel dots, making them swell or shrink. Rheological measurements allowed for selecting hydrogels that withstand long-term shear forces present in microfluidic devices under continuous flow. Once implemented, the thiol-disulfide exchange allowed the hydrogel dots to successfully capture and release the protein bovine serum albumin (BSA). BSA was labeled with rhodamine B and functionalized with 2-(2-pyridyldithio)-ethylamine (PDA) to introduce disulfide bonds. The reversible capture and release of the protein reached an efficiency of 83.6% in release rate and could be repeated over 3 cycles within the microfluidic device. These results demonstrate that our redox-responsive hydrogel dots enable the dynamic capture and release of various different functionalized (macro)molecules (e.g., proteins and drugs) and have a great potential to be integrated into a lab-on-a-chip device for detection and/or delivery.

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Phase-Separating Peptides for Direct Cytosolic Delivery and Redox-Activated Release of Macromolecular Therapeutics.

10.21203/rs.3.rs-181485/v1 ◽

2021 ◽

Author(s):

Yue Sun ◽

Sze Yi Lau ◽

Zhi Wei Lim ◽

Shi Chieh Chang ◽

Farid Ghadessy ◽

...

Keyword(s):

Metabolic Diseases ◽

Transfection Efficiency ◽

Cellular Membrane ◽

Small Peptides ◽

Therapeutic Modalities ◽

Cytosolic Delivery ◽

Wide Range ◽

Redox Responsive ◽

Intracellular Targets ◽

Liquid Liquid Phase Separation

Abstract Biomacromolecules are highly promising therapeutic modalities to treat various diseases. However, they suffer from poor cellular membrane permeability, limiting their access to intracellular targets. Strategies to overcome this challenge employ nanoscale carriers that often get trapped in endosome compartments. Here, we report on conjugated peptides forming pH- and redox-responsive coacervate microdroplets by liquid-liquid phase separation (LLPS) that readily cross the cell membrane. A wide range of macromolecules can be quickly recruited within the microdroplets, from small peptides to enzymes as large as 430 kDa to mRNAs. The therapeutic-loaded coacervates bypass endocytosis to directly enter in the cytosol, where they undergo glutathione-mediated release of payload whose bioactivity is retained in the cell, whereas mRNAs exhibit a high transfection efficiency. These peptide coacervates represent a promising platform for intracellular delivery of a large palette of macromolecular therapeutics that have potential in the treatment of various pathologies (e.g. cancers and metabolic diseases), or as carriers for mRNA-based vaccines.

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Factors Affecting Formation of Metastable Ni3C Phase in a Solution-Based Method

Journal of Nanoscience and Nanotechnology ◽

10.1166/jnn.2008.296 ◽

2008 ◽

Vol 8 (9) ◽

pp. 4477-4481 ◽

Cited By ~ 16

Author(s):

Yonghua Leng ◽

Yang Liu ◽

Xubo Song ◽

Xingguo Li

Keyword(s):

Organic Molecule ◽

Nickel Nanoparticles ◽

Ni Nanoparticles ◽

Organic Solution ◽

Reaction Conditions ◽

Factors Affecting ◽

Diffusion Controlled ◽

Wide Range ◽

Organometallic Precursors ◽

Carbon Component

Ni3C nanoparticles are synthesized over a wide range of reaction conditions by thermal decomposition of organometallic precursors in the organic solution medium. It is found that Ni3C nanoparticles are formed using Ni nanoparticles as an intermediate. The carbon component originating from the organic solution medium to enter into Ni metal lattice is identified as a diffusion-controlled reaction, which is speeded up by increasing the reaction temperature and completed by prolonging the reaction time. Any organic molecule which contains active carbon atoms is found to be a good candidate as carbon source and combine with nickel nanoparticles to form Ni3C phase. Although this paper emphasizes on the preparation of metastable Ni3C phase, at the same time, this work could effectively direct the synthesis of Ni nanoparticles in organic solution, by avoiding the formation of Ni3C phase.

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Multifunctional photoresponsive organic molecule for electric field sensing and modulation

Journal of Materials Chemistry C ◽

10.1039/d1tc05065f ◽

2021 ◽

Author(s):

Yingmu Zhang ◽

Jinghan He ◽

Patrick Saris ◽

Hyun Uk Chae ◽

Subrata Das ◽

...

Keyword(s):

Electric Field ◽

Nonlinear Optical ◽

Organic Molecule ◽

Organic Molecules ◽

Molecular Design ◽

Biological Imaging ◽

Integrated Photonics ◽

Electric Field Sensing ◽

Wide Range ◽

Field Sensing

Nonlinear optical organic molecules have advanced a wide range of fields spanning from integrated photonics to biological imaging. With advances in molecular design, an emerging application is multifunctional nonlinear organic...

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Ruthenium-Catalyzed [2+2+2] Cycloaddition of α,ω-Diynes and Selenocyanates: An Entry to Selenopyridine Derivatives

Synthesis ◽

10.1055/s-0037-1610704 ◽

2019 ◽

Vol 51 (12) ◽

pp. 2532-2541 ◽

Cited By ~ 2

Author(s):

Christine Tran ◽

Mansour Haddad ◽

Virginie Ratovelomanana-Vidal

Keyword(s):

Ruthenium Complex ◽

Synthetic Method ◽

Wide Range ◽

Snar Reaction ◽

High Yields ◽

Post Functionalization

A novel synthetic method for the preparation of selenopyridine derivatives, involving a [2+2+2] cycloaddition of α,ω-diynes and selenocyanates that is catalyzed by a ruthenium complex is described. This mild and straightforward reaction allows access to a wide range of selenopyridines with high yields and excellent regioselectivities, using dichloromethane or dichloroethane as solvents, at either 50 or 80 °C. Post-functionalization of halogenated cycloadducts via cyanation using copper and SNAr reaction provides substituted selenopyridines with good yields.

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Recent Applications of High Resolution Electron Microscopy to Crystalline Arrays of Virus Particles

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100070199 ◽

1978 ◽

Vol 36 (3) ◽

pp. 470-482 ◽

Cited By ~ 1

Author(s):

R.W. Horne

Keyword(s):

Electron Microscopy ◽

Image Processing ◽

Analytical Techniques ◽

Staining Technique ◽

High Resolution Electron Microscopy ◽

Optical Diffraction ◽

Full Potential ◽

Virus Particles ◽

Resolution Electron ◽

Wide Range

The technique of surrounding virus particles with a neutralised electron dense stain was described at the Fourth International Congress on Electron Microscopy, Berlin 1958 (see Home & Brenner, 1960, p. 625). For many years the negative staining technique in one form or another, has been applied to a wide range of biological materials. However, the full potential of the method has only recently been explored following the development and applications of optical diffraction and computer image analytical techniques to electron micrographs (cf. De Hosier & Klug, 1968; Markham 1968; Crowther et al., 1970; Home & Markham, 1973; Klug & Berger, 1974; Crowther & Klug, 1975). These image processing procedures have allowed a more precise and quantitative approach to be made concerning the interpretation, measurement and reconstruction of repeating features in certain biological systems.

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Microfabrication research at the National Submicron Facility

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100074331 ◽

1983 ◽

Vol 41 ◽

pp. 86-89

Author(s):

E.D. Wolf

Keyword(s):

Integrated Circuits ◽

Particle Physics ◽

High Speed ◽

New Technology ◽

High Energy ◽

High Energy Particle ◽

New Science ◽

Wide Range ◽

Intermediate Domain ◽

Circuit Function

Most microelectronics devices and circuits operate faster, consume less power, execute more functions and cost less per circuit function when the feature-sizes internal to the devices and circuits are made smaller. This is part of the stimulus for the Very High-Speed Integrated Circuits (VHSIC) program. There is also a need for smaller, more sensitive sensors in a wide range of disciplines that includes electrochemistry, neurophysiology and ultra-high pressure solid state research. There is often fundamental new science (and sometimes new technology) to be revealed (and used) when a basic parameter such as size is extended to new dimensions, as is evident at the two extremes of smallness and largeness, high energy particle physics and cosmology, respectively. However, there is also a very important intermediate domain of size that spans from the diameter of a small cluster of atoms up to near one micrometer which may also have just as profound effects on society as “big” physics.

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Application of TEM to Deformation, Wear, and Fracture of Ceramics

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100052377 ◽

1974 ◽

Vol 32 ◽

pp. 472-473

Author(s):

B. J. Hockey

Keyword(s):

Wear Resistance ◽

High Temperature ◽

Mechanical Behavior ◽

Brittle Materials ◽

High Temperature Strength ◽

Wide Range ◽

Corrosive Environments ◽

Further Development

Ceramics, such as Al2O3 and SiC have numerous current and potential uses in applications where high temperature strength, hardness, and wear resistance are required often in corrosive environments. These materials are, however, highly anisotropic and brittle, so that their mechanical behavior is often unpredictable. The further development of these materials will require a better understanding of the basic mechanisms controlling deformation, wear, and fracture.The purpose of this talk is to describe applications of TEM to the study of the deformation, wear, and fracture of Al2O3. Similar studies are currently being conducted on SiC and the techniques involved should be applicable to a wide range of hard, brittle materials.

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High Resolution Replication of Organoclay Surfaces

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100055126 ◽

1982 ◽

Vol 40 ◽

pp. 576-577

Author(s):

W. W. Barker ◽

W. E. Rigsby ◽

V. J. Hurst ◽

W. J. Humphreys

Keyword(s):

Clay Mineral ◽

Organic Molecule ◽

Organic Molecules ◽

X Ray Diffraction ◽

Xrd Pattern ◽

X Ray ◽

Naturally Occurring ◽

Silicate Layers ◽

Mineral Identification

Experimental clay mineral-organic molecule complexes long have been known and some of them have been extensively studied by X-ray diffraction methods. The organic molecules are adsorbed onto the surfaces of the clay minerals, or intercalated between the silicate layers. Natural organo-clays also are widely recognized but generally have not been well characterized. Widely used techniques for clay mineral identification involve treatment of the sample with H2 O2 or other oxidant to destroy any associated organics. This generally simplifies and intensifies the XRD pattern of the clay residue, but helps little with the characterization of the original organoclay. Adequate techniques for the direct observation of synthetic and naturally occurring organoclays are yet to be developed.

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