scholarly journals The Rheology of PEOT/PBT Block Copolymers in the Melt State and in the Thermally-Induced Sol/Gel Transition. Implications on the 3D-Printing Bio-Scaffold Process

Materials ◽  
2019 ◽  
Vol 12 (2) ◽  
pp. 226 ◽  
Author(s):  
Veronica Vanzanella ◽  
Marco Scatto ◽  
Erwin Zant ◽  
Michele Sisani ◽  
Maria Bastianini ◽  
...  
Keyword(s):  
Phase Transition ◽  
Block Copolymers ◽  
3D Printing ◽  
Sol Gel ◽  
Rheological Characterization ◽  
Thermally Induced ◽  
Low Viscosity ◽  
Oscillatory Shear Flow ◽  
Wide Range ◽  
Sol Gel Transition

Poly(ethyleneoxideterephthalate)/poly(butyleneterephthalate) (PEOT/PBT) segmented block copolymers are widely used for the manufacturing of 3D-printed bio-scaffolds, due to a combination of several properties, such as cell viability, bio-compatibility, and bio-degradability. Furthermore, they are characterized by a relatively low viscosity at high temperatures, which is desired during the injection stages of the printing process. At the same time, the microphase separated morphology generated by the demixing of hard and soft segments at intermediate temperatures allows for a quick transition from a liquid-like to a solid-like behavior, thus favoring the shaping and the dimensional stability of the scaffold. In this work, for the first time, the rheology of a commercial PEOT/PBT material is studied over a wide range of temperatures encompassing both the melt state and the phase transition regime. Non-isothermal viscoelastic measurements under oscillatory shear flow allow for a quantitative determination of the material processability in the melt state. Additionally, isothermal experiments below the order–disorder temperature are used to determine the temperature dependence of the phase transition kinetics. The importance of the rheological characterization when designing the 3D-printing scaffold process is also discussed.

scholarly journals Synthesis of Nanogels: Current Trends and Future Outlook

Gels ◽  
2021 ◽  
Vol 7 (2) ◽  
pp. 36
Author(s):  
Emanuele Mauri ◽  
Sara Maria Giannitelli ◽  
Marcella Trombetta ◽  
Alberto Rainer
Keyword(s):  
3D Printing ◽  
Ad Hoc ◽  
Sol Gel ◽  
Controlled Polymerization ◽  
Current Trends ◽  
Chip Technology ◽  
Physico Chemical ◽  
Physical Interactions ◽  
Sol Gel Transition ◽  
Gel Transition

Nanogels represent an innovative platform for tunable drug release and targeted therapy in several biomedical applications, ranging from cancer to neurological disorders. The design of these nanocarriers is a pivotal topic investigated by the researchers over the years, with the aim to optimize the procedures and provide advanced nanomaterials. Chemical reactions, physical interactions and the developments of engineered devices are the three main areas explored to overcome the shortcomings of the traditional nanofabrication approaches. This review proposes a focus on the current techniques used in nanogel design, highlighting the upgrades in physico-chemical methodologies, microfluidics and 3D printing. Polymers and biomolecules can be combined to produce ad hoc nanonetworks according to the final curative aims, preserving the criteria of biocompatibility and biodegradability. Controlled polymerization, interfacial reactions, sol-gel transition, manipulation of the fluids at the nanoscale, lab-on-a-chip technology and 3D printing are the leading strategies to lean on in the next future and offer new solutions to the critical healthcare scenarios.

Physical state of cellulose in BmimCl: dependence of molar mass on viscoelasticity and sol-gel transition

2016 ◽  
Vol 18 (3) ◽  
pp. 1460-1469 ◽  
Author(s):  
Yongjun Ahn ◽  
Seung-Yeop Kwak ◽  
Younghan Song ◽  
Hyungsup Kim
Keyword(s):  
Phase Transition ◽  
Ionic Liquid ◽  
Physical State ◽  
Molar Mass ◽  
Sol Gel ◽  
Cellulose Depolymerization ◽  
Sol Gel Transition ◽  
Gel Transition

Monitoring cellulose depolymerization and phase transition in ionic liquid.

Rheological characterization of BaTiO3 sol-gel transition

1997 ◽  
Vol 9 (1) ◽  
pp. 5-15 ◽  
Author(s):  
A. Brasseur ◽  
B. Michaux ◽  
R. Pirard ◽  
O. Van Cantfort ◽  
J. P. Pirard ◽  
...  
Keyword(s):  
Sol Gel ◽  
Rheological Characterization ◽  
Sol Gel Transition ◽  
Gel Transition

scholarly journals Major Role of Voluminosity in the Compressibility and Sol–Gel Transition of Casein Micelle Dispersions Concentrated at 7 °C and 20 °C

Foods ◽  
2019 ◽  
Vol 8 (12) ◽  
pp. 652
Author(s):  
Floriane Doudiès ◽  
Anne-Sophie Arsène ◽  
Fabienne Garnier-Lambrouin ◽  
Marie-Hélène Famelart ◽  
Antoine Bouchoux ◽  
...  
Keyword(s):  
Equilibrium Dialysis ◽  
Sol Gel ◽  
Casein Micelle ◽  
New Information ◽  
Wide Range ◽  
Sol Gel Transition ◽  
The Cost ◽  
Micelle Hydration ◽  
Gel Transition

The objective of this work is to bring new information about the influence of temperatures (7 °C and 20 °C) on the equation of state and sol–gel transition behavior of casein micelle dispersions. Casein micelle dispersions have been concentrated and equilibrated at different osmotic pressures using equilibrium dialysis at 7 °C and 20 °C. The osmotic stress technique measured the osmotic pressures of the dispersions over a wide range of concentrations. Rheological properties of concentrated dispersions were then characterized, respectively at 7 °C and at 20 °C. The essential result is that casein micelle dispersions are less compressible at 7 °C than at 20 °C and that concentration of sol–gel transition is lower at 7 °C than at 20 °C, with compressibility defined as the inverse to the resistance to the compression, and that is proportional to the cost to remove water from structure. From our interpretations, these two features were fully consistent with a release of soluble β-casein and nanoclusters CaP and an increased casein micelle hydration and apparent voluminosity at 7 °C as compared with 20 °C.

scholarly journals Synthesis and Investigation of Thermo-Induced Gelation of Partially Cross-Linked Poly-2-isopropyl-2-oxazoline in Aqueous Media

Polymers ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 698 ◽  
Author(s):  
Alina Amirova ◽  
Serafim Rodchenko ◽  
Mikhail Kurlykin ◽  
Andrey Tenkovtsev ◽  
Illia Krasnou ◽  
...  
Keyword(s):  
Self Assembly ◽  
Sol Gel ◽  
Aqueous Media ◽  
Water Soluble ◽  
Thermally Induced ◽  
Thermosensitive Gel ◽  
Step Procedure ◽  
Physical Gel ◽  
Sol Gel Transition ◽  
Gel Transition

Water-soluble, partially cross-linked poly-2-isopropyl-2-oxazoline combining the properties of chemical and physical gels was synthesized by a two-step procedure. Thermally induced sol-gel transition in its aqueous solution was studied by rheology, light scattering, and turbidimetry. It was demonstrated that the synthesized product is bimodal; it consists of linear and cross-linked components. The cross-linked components are responsible for the gelation, while the linear ones abate the viscosity growth. Heating the solution above the phase transition temperature leads to the self-assembly of the particles into a physical gel. The combination of chemical and physical cross-linking was found to be a prospective route for thermosensitive gel development.

scholarly journals Unravelling a Novel Sol-Gel Transition Mechanism in Polymer Self-Assemblies: An Order-Order Transition Based on Specific Molecular Interactions Between Hydrophilic and Hydrophobic Polymer Blocks

2021 ◽  
Author(s):  
Lukas Hahn ◽  
Theresa Zorn ◽  
Josef Kehrrein ◽  
Tobias Kielholz ◽  
Benedikt Sochor ◽  
...  
Keyword(s):  
Self Assembly ◽  
Sol Gel ◽  
Analytical Techniques ◽  
Order Transition ◽  
Dynamics Simulation ◽  
Aqueous Polymer ◽  
Transition Mechanism ◽  
Wide Range ◽  
Spherical Micelles ◽  
Sol Gel Transition

Using a wide range of state-of-the art analytical techniques and molecular dynamics simulation, a novel mechanism for macromolecular interactions are described. Distinct interactions between the hydrophilic and hydrophobic blocks in amphiphilic triblock copolymers lead to an order-order transition from spherical micelles to worm-like micelles upon cooling the aqueous polymer solutions below room temperature. Macroscopically, this this leads to reversible gelation. This novel mechanism represent a novel building block to better understand polymer self-assembly.<br>

Green processing of thermosensitive nanocurcumin-encapsulated chitosan hydrogel towards biomedical application

2016 ◽  
Vol 5 (6) ◽  
Author(s):  
Thi Bich Tram Nguyen ◽  
Le Hang Dang ◽  
Thi Thanh Thuy Nguyen ◽  
Dai Lam Tran ◽  
Dai Hai Nguyen ◽  
...  
Keyword(s):  
Biomedical Application ◽  
Sol Gel ◽  
Aqueous Solubility ◽  
Free Form ◽  
Rheological Characterization ◽  
Synthetic Process ◽  
Thermally Responsive ◽  
Green Processing ◽  
Sol Gel Transition ◽  
Pharmaceutical Agents

AbstractIn this study, in order to enhance the aqueous solubility and to overcome the limitation of curcumin (Cur) in free form, as well as to develop a carrier for transdermal delivery of hydrophobic pharmaceutical agents such as Cur, a sonicated synthetic process of nanocurcumin (nCur) in thermally responsive Chitosan-g-Pluronic (CP) copolymer is disclosed herein. The use of CP copolymer solution as a dispersant medium is a very attractive method to avoid the use of toxic organic solvent and non-biocompatible surfactant. The obtained Cur nanoparticles had a fairly narrow distribution of 8–23 nm. nCur-dispersed CP solution showed good stability with no change in color characteristic and no phase separation after 1 month of storage. Rheological characterization of CP hydrogels had indicated sol-gel transition at the same temperature (35°C). Interestingly, the rate of Cur release for this system can be conveniently modulated as transdermal drug delivery.

In situ formed thermogelable hydrogel photonic crystals assembled by thermosensitive IPNs

2021 ◽  
Author(s):  
Xiaoxiao Li ◽  
Di Zhao ◽  
Kenneth J. Shea ◽  
Xueting Li ◽  
Xihua Lu
Keyword(s):  
Phase Transition ◽  
Transition Temperature ◽  
Photonic Crystals ◽  
Phase Transition Temperature ◽  
Sol Gel ◽  
Significant Advance ◽  
Sol Gel Transition ◽  
Gel Transition

In this paper, soft thermosensitive photonic crystals are immobilized via a reversible temperature-triggered in situ sol–gel transition above their phase transition temperature (Tp), which may be a significant advance in the field.

scholarly journals 3D Printing of a Reactive Hydrogel Bio-Ink Using a Static Mixing Tool

Polymers ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 1986 ◽  
Author(s):  
María Puertas-Bartolomé ◽  
Małgorzata K. Włodarczyk-Biegun ◽  
Aránzazu del Campo ◽  
Blanca Vázquez-Lasa ◽  
Julio San Román
Keyword(s):  
3D Printing ◽  
Viscosity Solutions ◽  
Structural Integrity ◽  
Cell Types ◽  
High Viscosity ◽  
Soft Tissue Regeneration ◽  
Low Viscosity ◽  
Good Shape ◽  
Wide Range

Hydrogel-based bio-inks have recently attracted more attention for 3D printing applications in tissue engineering due to their remarkable intrinsic properties, such as a cell supporting environment. However, their usually weak mechanical properties lead to poor printability and low stability of the obtained structures. To obtain good shape fidelity, current approaches based on extrusion printing use high viscosity solutions, which can compromise cell viability. This paper presents a novel bio-printing methodology based on a dual-syringe system with a static mixing tool that allows in situ crosslinking of a two-component hydrogel-based ink in the presence of living cells. The reactive hydrogel system consists of carboxymethyl chitosan (CMCh) and partially oxidized hyaluronic acid (HAox) that undergo fast self-covalent crosslinking via Schiff base formation. This new approach allows us to use low viscosity solutions since in situ gelation provides the appropriate structural integrity to maintain the printed shape. The proposed bio-ink formulation was optimized to match crosslinking kinetics with the printing process and multi-layered 3D bio-printed scaffolds were successfully obtained. Printed scaffolds showed moderate swelling, good biocompatibility with embedded cells, and were mechanically stable after 14 days of the cell culture. We envision that this straightforward, powerful, and generalizable printing approach can be used for a wide range of materials, growth factors, or cell types, to be employed for soft tissue regeneration.

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