A bioprinted composite hydrogel with controlled shear stress on cells

In recent decades, three dimensional (3D) bio-printing technology has found widespread use in tissue engineering applications. The aim of this study is to scrutinize different parameters of the bioprinter – with the help of simulation software – to print a hydrogel so much so that avoid high amounts of shear stress which is detrimental for cell viability and cell proliferation. Rheology analysis was done on several hydrogels composed of different percentages of components: alginate, collagen, and gelatin. The results have led to the combination of percentages collagen:alginate:gelatin (1:4:8)% as the best condition which makes sol-gel transition at room temperature possible. The results have shown the highest diffusion rate and cell viability for the cross-linked sample with 1.5% CaCl2 for the duration of 1 h. Finally, we have succeeded in printing the hydrogel that is mechanically strong with suitable degradation rate and cell viability.

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A photophysical study of the sol/gel transition in silica: Structural dynamics and oscillations, room-temperature phosphorescence and photochromic gel glasses

Journal of Non-Crystalline Solids ◽

10.1016/0022-3093(86)90117-1 ◽

1986 ◽

Vol 82 (1-3) ◽

pp. 103-109 ◽

Cited By ~ 71

Author(s):

Vered R. Kaufman ◽

David Levy ◽

David Avnir

Keyword(s):

Structural Dynamics ◽

Room Temperature ◽

Sol Gel ◽

Room Temperature Phosphorescence ◽

Photophysical Study ◽

Sol Gel Transition ◽

Gel Glasses ◽

Gel Transition

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

Gels ◽

10.3390/gels7030078 ◽

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.

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Drug-Loaded Biocompatible Nanocarriers Embedded in Poloxamer 407 Hydrogels as Therapeutic Formulations

Medicines ◽

10.3390/medicines6010007 ◽

2018 ◽

Vol 6 (1) ◽

pp. 7 ◽

Cited By ~ 9

Author(s):

Elena Giuliano ◽

Donatella Paolino ◽

Massimo Fresta ◽

Donato Cosco

Keyword(s):

Controlled Release ◽

Biological Fluid ◽

Sol Gel ◽

Three Dimensional ◽

Delivery Systems ◽

Poloxamer 407 ◽

Temperature Dependent ◽

Sol Gel Transition ◽

Mixed Systems ◽

Gel Transition

Hydrogels are three-dimensional networks of hydrophilic polymers able to absorb and retain a considerable amount of water or biological fluid while maintaining their structure. Among these, thermo-sensitive hydrogels, characterized by a temperature-dependent sol–gel transition, have been massively used as drug delivery systems for the controlled release of various bioactives. Poloxamer 407 (P407) is an ABA-type triblock copolymer with a center block of hydrophobic polypropylene oxide (PPO) between two hydrophilic polyethyleneoxide (PEO) lateral chains. Due to its unique thermo-reversible gelation properties, P407 has been widely investigated as a temperature-responsive material. The gelation phenomenon of P407 aqueous solutions is reversible and characterized by a sol–gel transition temperature. The nanoencapsulation of drugs within biocompatible delivery systems dispersed in P407 hydrogels is a strategy used to increase the local residence time of various bioactives at the injection site. In this mini-review, the state of the art of the most important mixed systems made up of colloidal carriers localized within a P407 hydrogel will be provided in order to illustrate the possibility of obtaining a controlled release of the entrapped drugs and an increase in their therapeutic efficacy as a function of the biomaterial used.

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Pyrene-Based Co-Assembled Supramolecular Gel; Morphology Changes and Macroscale Mechanical Property

Gels ◽

10.3390/gels6020016 ◽

2020 ◽

Vol 6 (2) ◽

pp. 16

Author(s):

Ka Young Kim ◽

Mirae Ok ◽

Jaehyeong Kim ◽

Sung Ho Jung ◽

Moo Lyong Seo ◽

...

Keyword(s):

Sol Gel ◽

Three Dimensional ◽

Inversion Method ◽

Supramolecular Gel ◽

Molar Ratios ◽

Dimensional Network ◽

Supramolecular Gels ◽

Pyrene Derivatives ◽

Sol Gel Transition ◽

Gel Transition

Two pyrene derivatives having the perylenediimide (1) or the alky chain (2) in the middle of molecules were synthesized. Co-assembled supramolecular gels were prepared at different molar ratios of 0.2, 0.5, and 0.8 equiv. of 2 to 1. By SEM observation, the morphology of co-assembled supramolecular gels changed from spherical nanoparticles to three-dimensional network nanofibers as the ratio of 2 increased. In addition, the pyrene-excimer emission of co-assembled gels increased with increasing concentration of 2, and was stronger when compared with the condition without 1 or 2, indicating the formation of pyrene interaction between 1 and 2. In addition, the sol-gel transition was found to be reversible over repeated measurement by tube inversion method. The rheological properties of co-assembled supramolecular gels were also improved by increasing the ratio of 2, due to the increased nanoscale flexibility of supramolecular packing by introducing alkyl chain groups through heterogeneous pyrene interaction. These findings suggest that macroscale mechanical strength of co-assembled supramolecular gel was strongly influenced by nanoscale flexibility of the supramolecular packing.

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Clay–graphene oxide liquid crystals and their aerogels: synthesis, characterization and properties

Royal Society Open Science ◽

10.1098/rsos.181439 ◽

2019 ◽

Vol 6 (2) ◽

pp. 181439 ◽

Cited By ~ 2

Author(s):

Sisi Ye ◽

Zhihong Yang ◽

Jianmei Xu ◽

Zehao Shang ◽

Jing Xie

Keyword(s):

Graphene Oxide ◽

Liquid Crystals ◽

Adsorption Capacity ◽

Sol Gel ◽

Three Dimensional ◽

Anionic Dyes ◽

Porous Network ◽

Mass Fractions ◽

Sol Gel Transition ◽

Gel Transition

The dispersions containing two kinds of layered solids—graphene oxide (GO) and exfoliated montmorillonite (MMT) were mainly prepared, following which the binary aerogels were synthesized. The results indicate that the formation of liquid crystals (LCs) occurs at lower GO concentration and the birefringence becomes stronger when MMT is introduced into GO dispersion. Sol–gel transition forms in the binary suspensions with different mass fractions of MMT and GO. LCs with highly ordered alignment are observed in the gel and the fraction of LCs obviously increases with the increase in GO concentration. Moreover, the birefringence is observed in MMT–GO binary aerogels with the interconnected three-dimensional porous network, which is attributed to the ordered arrangement of MMT and GO nanosheets in pore walls. Among the aerogels with different MMT/GO ratios, the samples at the ratio of 10 : 1 show better adsorption capacity and removal percentage of cationic and anionic dyes.

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Sol-gel transition in silica alkaline solutions. A NMR study

Journal de Chimie Physique ◽

10.1051/jcp/1994910901 ◽

1994 ◽

Vol 91 ◽

pp. 901-908 ◽

Cited By ~ 2

Author(s):

H Zanni ◽

P Nieto ◽

L Fernandez ◽

R Couty ◽

P Barret ◽

...

Keyword(s):

Sol Gel ◽

Alkaline Solutions ◽

Nmr Study ◽

Sol Gel Transition ◽

Gel Transition

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Sol-gel transition in agar-gelatin mixtures studied with transient elastography

IEEE Transactions on Ultrasonics Ferroelectrics and Frequency Control ◽

10.1109/tuffc.2006.1621498 ◽

2006 ◽

Vol 53 (4) ◽

pp. 716-723 ◽

Cited By ~ 26

Author(s):

J.-L. Gennisson ◽

G. Cloutier

Keyword(s):

Transient Elastography ◽

Sol Gel ◽

Sol Gel Transition ◽

Gel Transition

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Synthesis of Nanogels: Current Trends and Future Outlook

Gels ◽

10.3390/gels7020036 ◽

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.

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