scholarly journals Improved method for synthesis of cysteine modified hyaluronic acid for in situ hydrogel formation

2015 ◽  
Vol 51 (47) ◽  
pp. 9662-9665 ◽  
Author(s):  
Xin Zhang ◽  
Pengcheng Sun ◽  
Lingzi Huangshan ◽  
Bi-Huang Hu ◽  
Phillip B. Messersmith
Keyword(s):  
Hyaluronic Acid ◽  
Chemical Modification ◽  
Hydroxyl Groups ◽  
Improved Method ◽  
Ether Bond ◽  
Hydrogel Formation ◽  
New Strategy ◽  
In Situ Hydrogel ◽  
Acid Conjugate

We developed a new strategy for the functionalization of hyaluronic acid by chemical modification of its C-6 hydroxyl groups through an ether bond to obtain a cysteine–hyaluronic acid conjugate.

Thermosensitive in situ hydrogel based on the hybrid of hyaluronic acid and modified PCL/PEG triblock copolymer

2014 ◽  
Vol 108 ◽  
pp. 26-33 ◽  
Author(s):  
Zesheng Lv ◽  
Longlong Chang ◽  
Xingwen Long ◽  
Jianping Liu ◽  
Yuzhang Xiang ◽  
...  
Keyword(s):  
Hyaluronic Acid ◽  
Triblock Copolymer ◽  
In Situ Hydrogel

scholarly journals Fabrication of Injectable, Porous Hyaluronic Acid Hydrogel Based on an In-Situ Bubble-Forming Hydrogel Entrapment Process

Polymers ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 1138
Author(s):  
Lixuan Wang ◽  
Shiyan Dong ◽  
Yutong Liu ◽  
Yifan Ma ◽  
Jingjing Zhang ◽  
...  
Keyword(s):  
Hyaluronic Acid ◽  
Regenerative Medicine ◽  
In Vivo Studies ◽  
Injectable Hydrogels ◽  
Cell Behaviors ◽  
Porous Architecture ◽  
In Situ Hydrogel

Injectable hydrogels have been widely applied in the field of regenerative medicine. However, current techniques for injectable hydrogels are facing a challenge when trying to generate a biomimetic, porous architecture that is well-acknowledged to facilitate cell behaviors. In this study, an injectable, interconnected, porous hyaluronic acid (HA) hydrogel based on an in-situ bubble self-generation and entrapment process was developed. Through an amide reaction between HA and cystamine dihydrochloride activated by EDC/NHS, CO2 bubbles were generated and were subsequently entrapped inside the substrate due to a rapid gelation-induced retention effect. HA hydrogels with different molecular weights and concentrations were prepared and the effects of the hydrogel precursor solution’s concentration and viscosity on the properties of hydrogels were investigated. The results showed that HA10-10 (10 wt.%, MW 100,000 Da) and HA20-2.5 (2.5 wt.%, MW 200,000 Da) exhibited desirable gelation and obvious porous structure. Moreover, HA10-10 represented a high elastic modulus (32 kPa). According to the further in vitro and in vivo studies, all the hydrogels prepared in this study show favorable biocompatibility for desirable cell behaviors and mild host response. Overall, such an in-situ hydrogel with a self-forming bubble and entrapment strategy is believed to provide a robust and versatile platform to engineer injectable hydrogels for a variety of applications in tissue engineering, regenerative medicine, and personalized therapeutics.

PEG–PLLA and PEG–PDLA multiblock copolymers: Synthesis and in situ hydrogel formation by stereocomplexation

2006 ◽  
Vol 116 (2) ◽  
pp. e17-e19 ◽  
Author(s):  
C. Hiemstra ◽  
Z.Y. Zhong ◽  
X. Jiang ◽  
W.E. Hennink ◽  
P.J. Dijkstra ◽  
...  
Keyword(s):  
Multiblock Copolymers ◽  
Hydrogel Formation ◽  
In Situ Hydrogel

Cyclodextrin–dextran based in situ hydrogel formation: a carrier for hydrophobic drugs

Soft Matter ◽  
2010 ◽  
Vol 6 (1) ◽  
pp. 85-87 ◽  
Author(s):  
Ke Peng ◽  
Itsuro Tomatsu ◽  
Alexander V. Korobko ◽  
Alexander Kros
Keyword(s):  
Hydrophobic Drugs ◽  
Hydrogel Formation ◽  
In Situ Hydrogel

Preparation of HA Hydrogel by Click Chemistry

2015 ◽  
Vol 1088 ◽  
pp. 286-289
Author(s):  
Yuan Cui ◽  
Jing Peng Zhang ◽  
Wei Zhang ◽  
Qian Duan
Keyword(s):  
Hyaluronic Acid ◽  
Click Chemistry ◽  
Molecular Design ◽  
Click Reaction ◽  
Side Chains ◽  
H Nmr ◽  
Hydrogel Formation

"Click chemistry" was used in this paper to get a novel hyaluronic acid (HA) hydrogel by modified HA molecules' side chains with azide and alkynyl groups to perform "Click" reaction. The HA hydrogel can be achieved "in situ" injection gel. The properties of the HA hydrogel can be controlled by controlling the amount of alkynyl and azide groups on side chains to achieve controllable HA hydrogel by HA molecular design. The reactant, product and hydrogel were characterized by 1H NMR, FTIR and morphology observation to determine the processes of reaction and can hydrogel formation.

scholarly journals F/OH ratio in a rare fluorine-poor blue topaz from Padre Paraíso (Minas Gerais, Brazil) to unravel topaz’s ambient of formation

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
N. Precisvalle ◽  
A. Martucci ◽  
L. Gigli ◽  
J. R. Plaisier ◽  
T. C. Hansen ◽  
...  
Keyword(s):  
Supercritical Fluids ◽  
Fluorine Content ◽  
Minas Gerais ◽  
Hydroxyl Groups ◽  
Exchange Reactions ◽  
Silicate System ◽  
Mullite Phase ◽  
Anomalous Water

AbstractTopaz [Al2SiO4(F,OH)2] is one of the main fluorine-bearing silicates occurring in environments where variably acidic (F)/aqueous (OH) fluids saturate the silicate system. In this work we fully characterized blue topaz from Padre Paraíso (Minas Gerais, Brazil) by means of in situ synchrotron X-Ray and neutron powder diffraction measurements (temperature range 298–1273 K) combined with EDS microanalyses. Understanding the role of OH/F substitution in topaz is important in order to determine the hydrophilicity and the exchange reactions of fluorine by hydroxyl groups, and ultimately to characterize the environmental redox conditions (H2O/F) required for mineral formation. The fluorine content estimated from neutron diffraction data is ~ 1.03 a.f.u (10.34 wt%), in agreement with the chemical data (on average 10.0 wt%). The XOH [OH/(OH + F)] (0.484) is close to the maximum XOH value (0.5), and represents the OH- richest topaz composition so far analysed in the Minas Gerais district. Topaz crystallinity and fluorine content sharply decrease at 1170 K, while mullite phase starts growing. On the basis of this behaviour, we suggest that this temperature may represent the potential initial topaz’s crystallization temperature from supercritical fluids in a pegmatite system. The log(fH2O/fHF)fluid (1.27 (0.06)) is coherent with the fluorine activity calculated for hydrothermal fluids (pegmatitic stage) in equilibrium with the forming mineral (log(fH2O/fHF)fluid = 1.2–6.5) and clearly different from pure magmatic (granitic) residual melts [log(fH2O/fHF)fluid < 1]. The modelled H2O saturated fluids with the F content not exceeding 1 wt% may represent an anomalous water-dominant / fluorine-poor pegmatite lens of the Padre Paraíso Pegmatite Field.

scholarly journals Morphology Controlled Synthesis of γ-Al2O3 Nano-Crystallites in Al@Al2O3 Core–Shell Micro-Architectures by Interfacial Hydrothermal Reactions of Al Metal Substrates

Nanomaterials ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 310
Author(s):  
Dohyeon Han ◽  
Doohwan Lee
Keyword(s):  
Electrostatic Interactions ◽  
Heterogeneous Catalysts ◽  
Metal Substrate ◽  
Inorganic Anions ◽  
Core Shell ◽  
Hydroxyl Groups ◽  
Hydrothermal Reactions ◽  
Fine Control ◽  
Reaction Processes

Fine control of morphology and exposed crystal facets of porous γ-Al2O3 is of significant importance in many application areas such as functional nanomaterials and heterogeneous catalysts. Herein, a morphology controlled in situ synthesis of Al@Al2O3 core–shell architecture consisting of an Al metal core and a porous γ-Al2O3 shell is explored based on interfacial hydrothermal reactions of an Al metal substrate in aqueous solutions of inorganic anions. It was found that the morphology and structure of boehmite (γ-AlOOH) nano-crystallites grown at the Al-metal/solution interface exhibit significant dependence on temperature, type of inorganic anions (Cl−, NO3−, and SO42−), and acid–base environment of the synthesis solution. Different extents of the electrostatic interactions between the protonated hydroxyl groups on (010) and (001) facets of γ-AlOOH and the inorganic anions (Cl−, NO3−, SO42−) appear to result in the preferential growth of γ-AlOOH toward specific crystallographic directions due to the selective capping of the facets by adsorption of the anions. It is hypothesized that the unique Al@Al2O3 core–shell architecture with controlled morphology and exposed crystal-facets of the γ-Al2O3 shell can provide significant intrinsic catalytic properties with enhanced heat and mass transport to heterogeneous catalysts for applications in many thermochemical reaction processes. The direct fabrication of γ-Al2O3 nano-crystallites from Al metal substrate with in-situ modulation of their morphologies and structures into 1D, 2D, and 3D nano-architectures explored in this work is unique and can offer significant opportunities over the conventional methods.

scholarly journals Effect of Na- and Organo-Modified Montmorillonite/Essential Oil Nanohybrids on the Kinetics of the In Situ Radical Polymerization of Styrene

Nanomaterials ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 474
Author(s):  
Ioannis S. Tsagkalias ◽  
Alexandra Loukidi ◽  
Stella Chatzimichailidou ◽  
Constantinos E. Salmas ◽  
Aris E. Giannakas ◽  
...  
Keyword(s):  
Essential Oil ◽  
Radical Polymerization ◽  
Food Packaging ◽  
In Situ Polymerization ◽  
Average Molecular Weight ◽  
Monomer Conversion ◽  
Hydroxyl Groups ◽  
Modified Montmorillonite ◽  
Kinetics Of

The great concern about the use of hazardous additives in food packaging materials has shown the way to new bio-based materials, such as nanoclays incorporating bioactive essential oils (EO). One of the still unresolved issues is the proper incorporation of these materials into a polymeric matrix. The in situ polymerization seems to be a promising technique, not requiring high temperatures or toxic solvents. Therefore, in this study, the bulk radical polymerization of styrene was investigated in the presence of sodium montmorillonite (NaMMT) and organo-modified montmorillonite (orgMMT) including thyme (TO), oregano (OO), and basil (BO) essential oil. It was found that the hydroxyl groups present in the main ingredients of TO and OO may participate in side retardation reactions leading to lower polymerization rates (measured gravimetrically by the variation of monomer conversion with time) accompanied by higher polymer average molecular weight (measured via GPC). The use of BO did not seem to affect significantly the polymerization kinetics and polymer MWD. These results were verified from independent experiments using model compounds, thymol, carvacrol and estragol instead of the clays. Partially intercalated structures were revealed from XRD scans. The glass transition temperature (from DSC) and the thermal stability (from TGA) of the nanocomposites formed were slightly increased from 95 to 98 °C and from 435 to 445 °C, respectively. Finally, better dispersion was observed when orgMMT was added instead of NaMMT.

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