NHC Polymeric Particles Obtained by Self-Assembly and Click Approach of Calix[4]Arene Amphiphiles as Support for Catalytically Active Pd Nanoclusters

A new polymeric NHC carrier was synthesized by sequential supramolecular self-assembly and copper-catalyzed azide-alkyne cycloaddition (CuAAC) of amphiphilic imidazolium calix[4]arenes with octyl lipophilic fragments. Obtained polytriazole-imidazolium particles were found as monodisperse submicron particles, with the average diameter of 236 ± 34 nm and average molecular weight of 1380 ± 96 kDa. Successful CuAAC polymerization has been proved using IR spectroscopy and high-resolution ESI mass spectrometry. Polymeric particles, as well as aggregates made from precursor macrocycles, were decorated by Pd clusters (2 nm) for further catalytic investigations. Pd nanoclusters, supported on the polymeric surface, were found highly catalytically active in the model reduction of p-nitrophenol, giving reaction rates an order of magnitude higher compared to literature examples. The reaction was recycled using the same catalyst five times without any loss of activity.

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Construction of Chitosan/Alginate Nano-Drug Delivery System for Improving Dextran Sodium Sulfate-Induced Colitis in Mice

Nanomaterials ◽

10.3390/nano11081884 ◽

2021 ◽

Vol 11 (8) ◽

pp. 1884

Author(s):

Mengfei Jin ◽

Shangyong Li ◽

Yanhong Wu ◽

Dandan Li ◽

Yantao Han

Keyword(s):

Self Assembly ◽

Average Diameter ◽

Mucosal Healing ◽

Plga Nanoparticles ◽

Narrow Particle Size Distribution ◽

Layer By Layer ◽

Systemic Side Effects ◽

Assembly Technology ◽

The Fourier Transform ◽

Polyelectrolyte Film

(1) Background: In the treatment of ulcerative colitis (UC), accurate delivery and release of anti-inflammatory drugs to the site of inflammation can reduce systemic side effects. (2) Methods: We took advantage of this goal to prepare resveratrol-loaded PLGA nanoparticles (RES-PCAC-NPs) by emulsification solvent volatilization. After layer-by-layer self-assembly technology, we deposited chitosan and alginate to form a three-layer polyelectrolyte film. (3) Results: It can transport nanoparticles through the gastric environment to target inflammation sites and slowly release drugs at a specific pH. The resulting RES-PCAC-NPs have an ideal average diameter (~255 nm), a narrow particle size distribution and a positively charged surface charge (~13.5 mV). The Fourier transform infrared spectroscopy showed that resveratrol was successfully encapsulated into PCAC nanoparticles, and the encapsulation efficiency reached 87.26%. In addition, fluorescence imaging showed that RES-PCAC-NPs with positive charges on the surface can effectively target and accumulate in the inflammation site while continuing to penetrate downward to promote mucosal healing. Importantly, oral RES-PCAC-NPs treatment in DSS-induced mice was superior to other results in significantly improved inflammatory markers of UC. (4) Conclusions: Our results strongly prove that RES-PCAC-NPs can target the inflamed colon for maximum efficacy, and this oral pharmaceutical formulation can represent a promising formulation in the treatment of UC.

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Mechanochemical and solvent-free assembly of zirconium-based metal–organic frameworks

Chemical Communications ◽

10.1039/c5cc08972g ◽

2016 ◽

Vol 52 (10) ◽

pp. 2133-2136 ◽

Cited By ~ 148

Author(s):

Krunoslav Užarević ◽

Timothy C. Wang ◽

Su-Young Moon ◽

Athena M. Fidelli ◽

Joseph T. Hupp ◽

...

Keyword(s):

Solid State ◽

High Temperatures ◽

Self Assembly ◽

Metal Organic Frameworks ◽

Accelerated Aging ◽

Solvent Free ◽

Catalytically Active ◽

Metal Organic ◽

Strong Acids ◽

Zirconium Metal

Mechanochemistry and accelerated aging are new routes to zirconium metal–organic frameworks, yielding UiO-66 and catalytically active UiO-66-NH2 accessible on the gram scale through mild solid-state self-assembly, without strong acids, high temperatures or excess reactants.

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From hollow lignin microsphere preparation to simultaneous preparation of urea encapsulation for controlled release using industrial kraft lignin via slow and exhaustive acetone-water evaporation

Holzforschung ◽

10.1515/hf-2019-0062 ◽

2019 ◽

Vol 74 (1) ◽

pp. 77-87 ◽

Cited By ~ 2

Author(s):

Miao Wang ◽

Yadong Zhao ◽

Jiebing Li

Keyword(s):

Controlled Release ◽

Self Assembly ◽

Average Diameter ◽

Kraft Lignin ◽

Water Evaporation ◽

Shell Wall ◽

Straightforward Method ◽

Acetone Water ◽

Direct Preparation ◽

Microsphere Preparation

AbstractLignin nano/microparticles have recently attracted growing interest for various value-additive applications of lignin, especially encapsulation. In this study, in order to establish a highly efficient and highly productive preparation process to effectively utilize technical lignin, a brand-new, slow and exhaustive solution evaporation process following a simple, self-assembly principle was developed using industrial softwood kraft lignin (SKL) from a starting acetone-water (80/20, v/v) solution to recover 100% of the lignin as homogeneous and well-shaped microspheres. The prepared microspheres had a typical average diameter of 0.81 ± 0.15 μm and were hollow with very thin shells (of nanoscale thickness). Based on this developed technique, encapsulation of urea by these lignin microspheres was directly achieved using the same process as hollow lignin microspheres with urea attached to the outside and entrapped inside of the wall. Two distinct urea release rates were observed for the urea-encapsulated microspheres: a fast release of the urea outside the shell wall and a slow (controlled) release of the urea inside the shell wall. The encapsulation efficiency was as high as 46% of the trapped urea as encapsulated inside the lignin microspheres. The slow and exhaustive solution evaporation procedure reported here is a simple and straightforward method for the valorization of industrial kraft lignin as hollow microspheres with controllable, homogeneous and desired morphologies, and especially for the direct preparation of lignin-based encapsulating fertilizers for controlled release.

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Electron Microscopy Study of Submicron Size Antiferromagnetic KMnF3 Nanoparticles and Their Self-assembly

MRS Proceedings ◽

10.1557/proc-775-p9.4 ◽

2003 ◽

Vol 775 ◽

Author(s):

Jeffrey Anderson ◽

Rubi Garcia ◽

Weilie L. Zhou

Keyword(s):

Electron Microscopy ◽

Self Assembly ◽

Room Temperature ◽

Microscopy Study ◽

Electron Microscopy Study ◽

Submicron Particles ◽

Spherical Particles ◽

Large Area ◽

Homogeneous Crystal ◽

Field Emission Electron Microscopy

AbstractSubmicron KMnF3 cubic and spherical nanoparticles were synthesized using the reverse micelle method. The nanostructures of the nanocrystals were studied by field emission electron microscopy and transmission electron microscopy. KMnF3 nanocrystals synthesized at room temperature started with cubic submicron particles (∼100 nm) and consisted of KMnF3 nanocrystallites (10-15 nm). As the reaction continued, the nanocrystals fused together and transformed into perfect cubic nanocrystals. Spherical beads composed of KMnF3 nanocrystallites were observed at low temperature synthesis. As the reaction continued, the spherical particles grew larger, however, no characteristic cubic shape of KMnF3 nanoparticles were observed. Even as they grew larger, there was no evidence of homogeneous crystal morphology as seen in the room temperature samples. Cubic shape KMnF3 nanocrystals were self-assembled into large area self-assembling patterns.

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Control of Chemical Reaction Pathways by Light–Matter Coupling

Annual Review of Physical Chemistry ◽

10.1146/annurev-physchem-090519-045502 ◽

2021 ◽

Vol 72 (1) ◽

Author(s):

Dinumol Devasia ◽

Ankita Das ◽

Varun Mohan ◽

Prashant K. Jain

Keyword(s):

Chemical Reactivity ◽

Reaction Rates ◽

Reaction Pathways ◽

Metal Nanostructures ◽

Annual Review ◽

Publication Date ◽

Strong Light ◽

Radical Intermediates ◽

Catalytically Active ◽

Light Excitation

Because plasmonic metal nanostructures combine strong light absorption with catalytically active surfaces, they have become platforms for the light-assisted catalysis of chemical reactions. The enhancement of reaction rates by plasmonic excitation has been extensively discussed. This review focuses on a less discussed aspect: the induction of new reaction pathways by light excitation. Through commentary on seminal reports, we describe the principles behind the optical modulation of chemical reactivity and selectivity on plasmonic metal nanostructures. Central to these phenomena are excited charge carriers generated by plasmonic excitation, which modify the energy landscape available to surface reactive species and unlock pathways not conventionally available in thermal catalysis. Photogenerated carriers can trigger bond dissociation or desorption in an adsorbate-selective manner, drive charge transfer and multielectron redox reactions, and generate radical intermediates. Through one or more of these mechanisms, a specific pathway becomes favored under light. By improved control over these mechanisms, light-assisted catalysis can be transformational for chemical synthesis and energy conversion. Expected final online publication date for the Annual Review of Physical Chemistry, Volume 72 is April 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

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Preparation and characterization of poly(styrenemethacrylic acid)/MCM-41 core/shell nanocomposite microspheres

e-Polymers ◽

10.1515/epoly.2009.9.1.1433 ◽

2009 ◽

Vol 9 (1) ◽

Author(s):

Yansheng Zhao ◽

Xingji Ma ◽

Yongmei Liu ◽

Guangwei Yuan ◽

Meijuan Guo ◽

...

Keyword(s):

Self Assembly ◽

Cetyltrimethylammonium Bromide ◽

Average Diameter ◽

Molar Ratio ◽

Core Shell ◽

Acidic Media ◽

Assembly Method ◽

20 Nm ◽

Mcm 41

AbstractIn acidic media, poly(styrene-methacrylic acid)/MCM-41 [P(St- MAA)/MCM-41] core/shell microspheres were synthesized using monodisperse P(St-MAA) particles contained in soap-free emulsion and cetyltrimethylammonium bromide as co-templates by adsorption self-assembly method. The effects of P(St- MAA) composition on shell structure of the core/shell microspheres were investigated. The morphology and composition of P(St-MAA)/MCM-41 microspheres were characterized by TEM, XRD and FTIR. The results show that the ordering degree of MCM-41 shells increased as the molar ratio of MAA to St increased. When n(MAA)/n(St) is 0.2, the average diameter and the shell thickness of nanocomposite microspheres are about 170 nm and 20 nm, respectively.

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Predictions of diffusion rates of organic molecules in secondary organic aerosols using the Stokes-Einstein and fractional Stokes-Einstein relations

10.5194/acp-2019-191 ◽

2019 ◽

Cited By ~ 1

Author(s):

Erin Evoy ◽

Adrian M. Maclean ◽

Grazia Rovelli ◽

Ying Li ◽

Alexandra P. Tsimpidi ◽

...

Keyword(s):

Citric Acid ◽

Organic Molecules ◽

Transport Model ◽

Reaction Rates ◽

Einstein Relation ◽

Acid Mixture ◽

Chemical Transport Model ◽

Order Of Magnitude ◽

Diffusion Rates ◽

Almost All

Abstract. Information on the rate of diffusion of organic molecules within secondary organic aerosol (SOA) is needed to accurately predict the effects of SOA on climate and air quality. Often, researchers have predicted diffusion rates of organic molecules within SOA using measurements of viscosity and the Stokes-Einstein relation (D ∝ 1/η where D is the diffusion coefficient and η is viscosity). However, the accuracy of this relation for predicting diffusion in SOA remains uncertain. We measured diffusion coefficients over eight orders in magnitude in proxies of SOA including citric acid, sorbitol, and a sucrose-citric acid mixture. These results were combined with literature data to evaluate the Stokes-Einstein relation for predicting diffusion of organic molecules in SOA. Although almost all the data agrees with the Stokes-Einstein relation within a factor of ten, a fractional Stokes-Einstein relation (D ∝ C/ηt) with t = 0.93 and C = 1.66 is a better model for predicting diffusion of organic molecules in the SOA proxies studied. In addition, based on the output from a chemical transport model, the Stokes-Einstein relation can over predict mixing times of organic molecules within SOA by as much as one order of magnitude at an altitude ~ 3 km, compared to the fractional Stokes-Einstein relation with t = 0.93 and C = 1.66. These differences can be important for predicting growth, evaporation, and reaction rates of SOA in the middle and upper part of the troposphere. These results also have implications for other areas where diffusion of organic molecules within organic-water matrices is important.

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Self-Assembly of Catalytically Active Supramolecular Coordination Compounds within Metal–Organic Frameworks

Journal of the American Chemical Society ◽

10.1021/jacs.9b03914 ◽

2019 ◽

Vol 141 (26) ◽

pp. 10350-10360 ◽

Cited By ~ 10

Author(s):

Rosa Adam ◽

Marta Mon ◽

Rossella Greco ◽

Lucas H. G. Kalinke ◽

Alejandro Vidal-Moya ◽

...

Keyword(s):

Self Assembly ◽

Coordination Compounds ◽

Metal Organic Frameworks ◽

Supramolecular Coordination ◽

Catalytically Active ◽

Metal Organic

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A Miniature pH Probe Using Functional Microfiber Bragg Grating

Optics ◽

10.3390/opt1020016 ◽

2020 ◽

Vol 1 (2) ◽

pp. 202-212 ◽

Cited By ~ 1

Author(s):

Yang Ran ◽

Peng Xiao ◽

Yongkang Zhang ◽

Deming Hu ◽

Zhiyuan Xu ◽

...

Keyword(s):

Self Assembly ◽

Ph Sensor ◽

Fiber Surface ◽

Bragg Grating ◽

Wavelength Shift ◽

Layer By Layer ◽

Compact Size ◽

Layer Technique ◽

Order Of Magnitude ◽

Ph Probes

Operando and precisely probing aqueous pH is fundamentally demanded, both in chemical and biological areas. Conventional pH probes, subjected to the larger size, are probably unfit for application in some extreme scenarios, such as a trace amount of samples. In this paper, we have further developed the pH sensor that leverages the microfiber Bragg grating with an ultra-compact size down to an order of magnitude of 10−14 m3. Using the electrostatic self-assembly layer-by-layer technique, the functional film consisting of sodium alginate, which harnesses a pH-dependent hygroscopicity, is immobilized on the fiber surface. Consequently, the alteration of aqueous pH could be quantitatively indicated by the wavelength shift of the grating resonance via the refractive index variation of the sensing film due to the water absorption or expulsion. The grating reflections involving fundamental mode and higher order mode exhibit the sensitivities of −72 pm/pH and −265 pm/pH, respectively. In addition, temperature compensation can be facilitated by the recording of the two reflections simultaneously. Furthermore, the modeling and simulation results predict the pivotal parameters of the configuration in sensitivity enhancement. The proposed proof-of-concept enriches the toolbox of pH sensor for catering to the need of detection in some extremely small spaces—for example, the living cells or the bio-tissues.

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Aspiration-assisted bioprinting for precise positioning of biologics

Science Advances ◽

10.1126/sciadv.aaw5111 ◽

2020 ◽

Vol 6 (10) ◽

pp. eaaw5111 ◽

Cited By ~ 19

Author(s):

Bugra Ayan ◽

Dong Nyoung Heo ◽

Zhifeng Zhang ◽

Madhuri Dey ◽

Adomas Povilianskas ◽

...

Keyword(s):

Self Assembly ◽

Physical Mechanism ◽

Single Cells ◽

Three Dimensional ◽

3D Bioprinting ◽

Precise Control ◽

3D Space ◽

Magnitude Range ◽

Wide Range ◽

Order Of Magnitude

Three-dimensional (3D) bioprinting is an appealing approach for building tissues; however, bioprinting of mini-tissue blocks (i.e., spheroids) with precise control on their positioning in 3D space has been a major obstacle. Here, we unveil “aspiration-assisted bioprinting (AAB),” which enables picking and bioprinting biologics in 3D through harnessing the power of aspiration forces, and when coupled with microvalve bioprinting, it facilitated different biofabrication schemes including scaffold-based or scaffold-free bioprinting at an unprecedented placement precision, ~11% with respect to the spheroid size. We studied the underlying physical mechanism of AAB to understand interactions between aspirated viscoelastic spheroids and physical governing forces during aspiration and bioprinting. We bioprinted a wide range of biologics with dimensions in an order-of-magnitude range including tissue spheroids (80 to 600 μm), tissue strands (~800 μm), or single cells (electrocytes, ~400 μm), and as applications, we illustrated the patterning of angiogenic sprouting spheroids and self-assembly of osteogenic spheroids.

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