Determination of Gelation Kinetic Parameters for a Chitosan/β-Glycerophosphate Injectable Hydrogel by Means of Rheological Measurement

2016 ◽  
Vol 848 ◽  
pp. 543-550 ◽  
Author(s):  
Qian Qian Wang ◽  
Da Jun Chen
Keyword(s):  
Sol Gel ◽  
Gelation Time ◽  
Transition Process ◽  
Reaction Rate Constant ◽  
Disodium Salt ◽  
Injectable Hydrogels ◽  
Rheological Measurement ◽  
Zero Order Kinetics ◽  
Thermosensitive Hydrogels ◽  
Sol Gel Transition

The aim of the current study was to improve the knowledge of the gelation process of injectable thermosensitive hydrogels comprising chitosan (CS) and β-glycerophosphate disodium salt (β-GP). The sol-gel transition process was precisely tracked by means of rheological measurement, in which the viscosity changed considerably with gelation time and temperature. The zero-order kinetics model was assumed to adequately describe the extent of gelation reaction. The reaction rate constant increased continuously with the increasing temperature and β-GP concentration. According to Arrhenius equation, the activation energies of gelation reaction for the chitosan injectable hydrogels were calculated as 64.38 KJ/mol, 101.68 KJ/mol and 140.92 KJ/mol for the samples containing 4% w/v, 6% w/v and 8% w/v of β-GP, respectively. It could be an effective way to study the gelation dynamics of injectable hydrogels, and provide references for clinical practice.

Viscoelastic Properties of Ceria Gel

2005 ◽  
Vol 480-481 ◽  
pp. 355-360
Author(s):  
Nopphawan Phonthammachai ◽  
Morakot Rumruangwong ◽  
Sirirat Jitkanka ◽  
Erdogan Gulari ◽  
Alexander M. Jamieson ◽  
...  
Keyword(s):  
Sol Gel ◽  
Gelation Time ◽  
Viscoelastic Behavior ◽  
Molar Ratio ◽  
Strength Parameter ◽  
Gel Point ◽  
Rheological Measurement ◽  
S Parameter ◽  
Storage And Loss Moduli ◽  
Sol Gel Transition

The viscoelastic behavior of different ceria gelling systems prepared through sol-gel transition were investigated by the rheological measurement. The gelation time was observed by the frequency independence of tand, and increased with increasing acid:alkoxide molar ratio. At the gel point, both storage and loss moduli (G’µ wn, G” µ wn)exhibited a power law dependence of applied frequency with n’ = n” = n. The viscoelastic exponents and gel strength parameter were dependent on the composition of system. The increase in HCl:alkoxide molar ratio increased the n value while decreased the S parameter.

Analyzing the Effects of Silica Nanospheres on the Sol–Gel Transition Profile of Thermosensitive Hydrogels

Langmuir ◽  
2021 ◽  
Author(s):  
Lucas S. Ribeiro ◽  
Renata L. Sala ◽  
Leticia A. O. de Jesus ◽  
Sandra A. Cruz ◽  
Emerson R. Camargo
Keyword(s):  
Sol Gel ◽  
Silica Nanospheres ◽  
Thermosensitive Hydrogels ◽  
Sol Gel Transition ◽  
Gel Transition ◽  
Transition Profile

Research on Sol-Gel Transition Process of Gelatin

2013 ◽  
Vol 683 ◽  
pp. 474-478
Author(s):  
Xi Liang Chen ◽  
Qing Nan Shi
Keyword(s):  
Numerical Simulation ◽  
Sol Gel ◽  
Transition Process ◽  
Controlled Drug Release ◽  
Simulation Method ◽  
Simulation Research ◽  
Gelation Process ◽  
Sol Gel Transition ◽  
And Performance ◽  
Gel Transition

As a kind of functional material, gelatin gel is widely used in controlled drug release, biological tissue engineering, photographic and food industries. Plenty of studies on the gelatin gel have been carried out by researchers, which include gelation mechanisms, gelation kinetics, analysis on the crosslinked structure and macroscopic performance during the gelation process. Numerical simulation is a new method used in the study of gelatin sol-gel transition process, which can make up for the deficiency of the experimental research. E.g., the dynamic gelation process makes it difficult to measure the structural and performance parameters in time and space scales in experiments. However, these problems have been solved by numerical simulation method in our previous work. The experimental, theoretical and numerical simulation research on sol-gel transition of gelatin is reviewed, and the progress and difficulties in this field are discussed.

An Overview of Injectable Thermo-Responsive Hydrogels and Advances in their Biomedical Applications

2020 ◽  
Vol 27 (34) ◽  
pp. 5773-5789
Author(s):  
Fabián Ávila-Salas ◽  
Esteban F. Durán-Lara
Keyword(s):  
Sol Gel ◽  
Bioactive Compound ◽  
Bioactive Molecules ◽  
Injectable Hydrogels ◽  
Multiple Features ◽  
Health Related Research ◽  
Human Body Temperature ◽  
Health Related ◽  
Sol Gel Transition ◽  
Responsive Hydrogels

Background:: Injectable hydrogels are a thermo-responsive system based on biomaterials. Injectable hydrogels have been broadly investigated mainly as vehicles or scaffolds of therapeutic agents that include drugs, proteins, cells, and bioactive molecules among others, utilized in the treatment of diseases such as cancers and the repair and regeneration of tissues. Results: : There are several studies that have described the multiple features of hydrogels. However, the main aspect that breaks the paradigm in the application of hydrogels is the thermoresponsiveness that some of them have, which is an abrupt modification in their properties in response to small variations in temperature. For that reason, the thermo-responsive hydrogels with the unique property of sol-gel transition have received special attention over the past decades. These hydrogels show phase transition near physiological human body temperature. This feature is key for being applied in promising areas of human health-related research. Conclusion: : The purpose of this study is the overview of injectable hydrogels and their latest advances in medical applications including bioactive compound delivery, tissue engineering, and regenerative medicine.

Preparation and Characterization of BaTiO3 Powders by Sol-Gel and BaTiO3 Ferroelectric Films by Electrophoretic Deposition Technique

2007 ◽  
Vol 280-283 ◽  
pp. 617-622
Author(s):  
Ya Lu Ma ◽  
Hong Long Zhu ◽  
Jian Lin Li
Keyword(s):  
Electrophoretic Deposition ◽  
Ph Value ◽  
Sol Gel ◽  
Transition Process ◽  
Deposition Technique ◽  
Ferroelectric Films ◽  
Electrical Field Strength ◽  
Powder Concentration ◽  
Sol Gel Transition ◽  
Gel Transition

The clear and transparent sols of BaTi acetate were prepared from tetrabutyltitanate, barium acetate aqueous solution, ethanol and acetic acid. The BaTi acetate sols were transferred into gels by sol-gel process, and the gels were dried and calcined to nanostructured BaTiO3 powders. Pure barium titanate powders added in mixtures of acetone and iodine and water or acetylacetone (Acac) and ethanol (EtOH) as suspension systems, the aim of this study was to use the electrophoretic deposition technique (EPD) to fabrication the BaTiO3 ferroelectric films with high dielectric constant. During sol-gel transition process, it is found that the initial PH value of sol affected not only the sol-gel transition, but also the particles size of the final calcined BaTiO3 powders. The effects of the EPD process parameters such as the suspension, powder concentration, electrical field strength on the specific EPD deposited weight were investigated. The films sintered at 1050°C for 2h were crystallized into the tetragonal phase at room temperature, which were sufficiently dense and had uniform microstructure and excellent dielectric properties.

Effects Of Trioxane On Silica Gel

1990 ◽  
Vol 180 ◽  
Author(s):  
Xiaoming Li ◽  
P.F. Johnson
Keyword(s):  
Elevated Temperature ◽  
Surface Density ◽  
Sol Gel ◽  
Gelation Time ◽  
Silica Gels ◽  
Glass Transitions ◽  
Structure And Properties ◽  
Thermal Reactions ◽  
Sol Gel Transition ◽  
Gel Transition

ABSTRACTHydrolysis, condensation and thermal reactions of silica gels derived from TEOS with and without 1,3,5-trioxane (C3H6O3) were studied. Effects of trioxane on viscosity and gelation time of solutions were determined. Specific surface, density, porosity and microhardness of gels were measured. The behavior of gels at elevated temperature was clarified using DTA, TGA, and dilatometry. The properties and structure of trioxane containing sol/gels may be explained by the role trioxane played in the sol-gel transition. The results of this investigation concerning sol-gel/gel-glass transitions, structure and properties of gels are presented.

scholarly journals In-Situ Forming pH and Thermosensitive Injectable Hydrogels to Stimulate Angiogenesis: Potential Candidates for Fast Bone Regeneration Applications

2020 ◽  
Vol 21 (5) ◽  
pp. 1633 ◽  
Author(s):  
Fatma Z. Kocak ◽  
Abdullah C.S. Talari ◽  
Muhammad Yar ◽  
Ihtesham U. Rehman
Keyword(s):  
Bone Regeneration ◽  
Sol Gel ◽  
Chorioallantoic Membrane ◽  
Cam Assay ◽  
Injectable Hydrogels ◽  
Angiogenic Potential ◽  
Homogeneous Solutions ◽  
Chick Chorioallantoic Membrane ◽  
Thermosensitive Hydrogels

Biomaterials that promote angiogenesis are required for repair and regeneration of bone. In-situ formed injectable hydrogels functionalised with bioactive agents, facilitating angiogenesis have high demand for bone regeneration. In this study, pH and thermosensitive hydrogels based on chitosan (CS) and hydroxyapatite (HA) composite materials loaded with heparin (Hep) were investigated for their pro-angiogenic potential. Hydrogel formulations with varying Hep concentrations were prepared by sol–gel technique for these homogeneous solutions were neutralised with sodium bicarbonate (NaHCO3) at 4 °C. Solutions (CS/HA/Hep) constituted hydrogels setting at 37 °C which was initiated from surface in 5–10 minutes. Hydrogels were characterised by performing injectability, gelation, rheology, morphology, chemical and biological analyses. Hydrogel solutions facilitated manual dropwise injection from 21 Gauge which is highly used for orthopaedic and dental administrations, and the maximum injection force measured through 19 G needle (17.191 ± 2.296N) was convenient for manual injections. Angiogenesis tests were performed by an ex-ovo chick chorioallantoic membrane (CAM) assay by applying injectable solutions on CAM, which produced in situ hydrogels. Hydrogels induced microvascularity in CAM assay this was confirmed by histology analyses. Hydrogels with lower concentration of Hep showed more efficiency in pro-angiogenic response. Thereof, novel injectable hydrogels inducing angiogenesis (CS/HA/Hep) are potential candidates for bone regeneration and drug delivery applications.

scholarly journals Tuning the Thermogelation and Rheology of Poly(2-Oxazoline)/Poly(2-Oxazine)s Based Thermosensitive Hydrogels for 3D Bioprinting

Gels ◽  
2021 ◽  
Vol 7 (3) ◽  
pp. 78
Author(s):  
Malik Salman Haider ◽  
Taufiq Ahmad ◽  
Mengshi Yang ◽  
Chen Hu ◽  
Lukas Hahn ◽  
...  
Keyword(s):  
Sol Gel ◽  
Three Dimensional ◽  
Homogeneous Distribution ◽  
Repeat Units ◽  
3D Network ◽  
Hydrogel Matrix ◽  
Thermosensitive Hydrogels ◽  
Sol Gel Transition ◽  
Highly Porous ◽  
Gel Transition

As one kind of “smart” material, thermogelling polymers find applications in biofabrication, drug delivery and regenerative medicine. In this work, we report a thermosensitive poly(2-oxazoline)/poly(2-oxazine) based diblock copolymer comprising thermosensitive/moderately hydrophobic poly(2-N-propyl-2-oxazine) (pPrOzi) and thermosensitive/moderately hydrophilic poly(2-ethyl-2-oxazoline) (pEtOx). Hydrogels were only formed when block length exceeded certain length (≈100 repeat units). The tube inversion and rheological tests showed that the material has then a reversible sol-gel transition above 25 wt.% concentration. Rheological tests further revealed a gel strength around 3 kPa, high shear thinning property and rapid shear recovery after stress, which are highly desirable properties for extrusion based three-dimensional (3D) (bio) printing. Attributed to the rheology profile, well resolved printability and high stackability (with added laponite) was also possible. (Cryo) scanning electron microscopy exhibited a highly porous, interconnected, 3D network. The sol-state at lower temperatures (in ice bath) facilitated the homogeneous distribution of (fluorescently labelled) human adipose derived stem cells (hADSCs) in the hydrogel matrix. Post-printing live/dead assays revealed that the hADSCs encapsulated within the hydrogel remained viable (≈97%). This thermoreversible and (bio) printable hydrogel demonstrated promising properties for use in tissue engineering applications.

Rheology and Heat Treatment of Zirconia Based Gels Synthesized from Sodium Glycozirconate Precursor

2005 ◽  
Vol 480-481 ◽  
pp. 549-556 ◽  
Author(s):  
Bussarin Ksapabutr ◽  
Erdogan Gulari ◽  
Sujitra Wongkasemjit
Keyword(s):  
Sol Gel ◽  
Gelation Time ◽  
X Ray Diffraction ◽  
Step Method ◽  
Storage And Loss Moduli ◽  
One Step ◽  
Sol Gel Transition ◽  
Bet Technique ◽  
The One ◽  
Kinetics Of

Zirconia based gels were prepared by the sol-gel route using sodium tris(glycozirconate)complex as precursor synthesized directly from the reaction of inexpensive and readily available compounds via the one step method. Rheological technique was used to investigate the sol-gel transition of zirconium based materials at different water/alkoxide ratios and reaction temperatures. The gelation time was determined from the evolution of the storage and loss moduli versus time at various frequencies using the Winter-Chambon criterion. The effect of an increase of the hydrolysis ratio and /or temperature was an enhancement of the kinetics of crosslink reactions, thus decreasing the gelation time. The variation of the gelation time versus temperature could be described by Arrhenius law. Furthermore, zirconia powders prepared from the thermal treatment at 500°C were analyzed by X-ray diffraction and the BET technique.

Sign in / Sign up

Export Citation Format

Share Document