scholarly journals Self-Healing, Stretchable, Biocompatible, and Conductive Alginate Hydrogels through Dynamic Covalent Bonds for Implantable Electronics

Polymers ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1133
Author(s):  
Yeonsun Choi ◽  
Kyuha Park ◽  
Heewon Choi ◽  
Donghee Son ◽  
Mikyung Shin
Keyword(s):  
Boronic Acid ◽  
Ex Vivo ◽  
Epigallocatechin Gallate ◽  
Self Healing ◽  
Covalent Bonds ◽  
Inflammatory Reactions ◽  
Simple Strategy ◽  
Alginate Hydrogels ◽  
Implantable Electronics ◽  
Conductive Hydrogels

Implantable electronics have recently been attracting attention because of the promising advances in personalized healthcare. They can be used to diagnose and treat chronic diseases by monitoring and applying bioelectrical signals to various organs. However, there are challenges regarding the rigidity and hardness of typical electronic devices that can trigger inflammatory reactions in tissues. In an effort to improve the physicochemical properties of conventional implantable electronics, soft hydrogel-based platforms have emerged as components of implantable electronics. It is important that they meet functional criteria, such as stretchability, biocompatibility, and self-healing. Herein, plant-inspired conductive alginate hydrogels composed of “boronic acid modified alginate” and “oligomerized epigallocatechin gallate,” which are extracted from plant compounds, are proposed. The conductive hydrogels show great stretchability up to 500% and self-healing properties because of the boronic acid-cis-diol dynamic covalent bonds. In addition, as a simple strategy to increase the electrical conductivity of the hydrogels, ionically crosslinked shells with cations (e.g., sodium) were generated on the hydrogel under physiological salt conditions. This decreased the resistance of the conductive hydrogel down to 900 ohm without trading off the original properties of stretchability and self-healing. The hydrogels were used for “electrophysiological bridging” to transfer electromyographic signals in an ex vivo muscle defect model, showing a great bridging effect comparable to that of a muscle-to-muscle contact model. The use of plant-inspired ionically conductive hydrogels is a promising strategy for designing implantable and self-healable bioelectronics.

Dynamic Bonds between Boronic Acid and Alginate: Hydrogels with Stretchable, Self-Healing, Stimuli-Responsive, Remoldable, and Adhesive Properties

2018 ◽  
Vol 19 (6) ◽  
pp. 2053-2061 ◽  
Author(s):  
Sang Hyeon Hong ◽  
Sunjin Kim ◽  
Joseph P. Park ◽  
Mikyung Shin ◽  
Keumyeon Kim ◽  
...  
Keyword(s):  
Boronic Acid ◽  
Self Healing ◽  
Stimuli Responsive ◽  
Adhesive Properties ◽  
Alginate Hydrogels

Imine Based Self-Healing Hydrogel Triggered by Periodate

2020 ◽  
Author(s):  
Alexis Wolfel ◽  
Cecilia Inés Alvarez Igarzabal ◽  
Marcelo Ricardo Romero
Keyword(s):  
Functional Groups ◽  
Time Window ◽  
Crosslinking Reaction ◽  
Self Healing ◽  
Swelling Properties ◽  
Covalent Bonds ◽  
Smart Systems ◽  
Primary Amino ◽  
Vicinal Diols ◽  
Aldehyde Groups

<p>Design of materials with novel sensitivities and smart behaviour is important for the development of smart systems with automated responsiveness. We have recently reported the synthesis of hydrogels, cross-linked by <i>N,N'</i>-diallyltartardiamide (DAT). The covalent DAT-crosslinking points have vicinal diols which can be easily cleaved with periodate, generating valuable a-oxo-aldehyde functional groups, useful for further chemical modification. Based on those findings, we envisioned that a self-healable hydrogel could be obtained by incorporation of primary amino functional groups, from <a>2-aminoethyl methacrylate </a>hydrochloride (AEMA), coexisting with DAT into the same network. The a-oxo-aldehyde groups generated after the reaction with periodate would arise in the immediate environment of amine groups to form imine cross-links. For this purpose, DAT-crosslinked hydrogels were synthesized and carefully characterized. The cleavage of DAT-crosslinks with periodate promoted changes in the mechanical and swelling properties of the materials. As expected, a self-healing behavior was observed, based on the spontaneous formation of imine covalent bonds. In addition, we surprisingly found a combination of fast vicinal diols cleavage and a low speed self-crosslinking reaction by imine formation. Consequently, it was found a time-window in which a periodate-treated polymer was obtained in a transient liquid state, which can be exploited to choose the final shape of the material, before automated gelling. The singular properties attained on these hydrogels could be useful for developing sensors, actuators, among other smart systems.</p>

scholarly journals Phenotypical and Functional Characteristics of Human Regulatory T Cells during Ex Vivo Maturation from CD4+ T Lymphocytes

2021 ◽  
Vol 11 (13) ◽  
pp. 5776
Author(s):  
Varvara G. Blinova ◽  
Natalia S. Novachly ◽  
Sofya N. Gippius ◽  
Abdullah Hilal ◽  
Yulia A. Gladilina ◽  
...  
Keyword(s):  
T Cells ◽  
Regulatory T Cells ◽  
Ex Vivo ◽  
Pcr Analysis ◽  
Mrna Levels ◽  
Rt Pcr ◽  
Inflammatory Reactions ◽  
Effector Cells ◽  
Cycle Regulation ◽  
Further Development

Regulatory T cells (Tregs) participate in the negative regulation of inflammatory reactions by suppressing effector cells. In a number of autoimmune disorders, the suppressive function and/or the number of Tregs is compromised. The lack of active functioning Tregs can be restored with adoptive transfer of expanded ex vivo autologous Tregs. In our study, we traced the differentiation and maturation of Tregs CD4+CD25+FoxP3+CD127low over 7 days of cultivation from initial CD4+ T cells under ex vivo conditions. The resulting ex vivo expanded cell population (eTregs) demonstrated the immune profile of Tregs with an increased capacity to suppress the proliferation of target effector cells. The expression of the FoxP3 gene was upregulated within the time of expansion and was associated with gradual demethylation in the promotor region of the T cell-specific demethylation region. Real-time RT-PCR analysis revealed changes in the expression profile of genes involved in cell cycle regulation. In addition to FOXP3, the cells displayed elevated mRNA levels of Ikaros zinc finger transcription factors and the main telomerase catalytic subunit hTERT. Alternative splicing of FoxP3, hTERT and IKZF family members was demonstrated to be involved in eTreg maturation. Our data indicate that expanded ex vivo eTregs develop a Treg-specific phenotype and functional suppressive activity. We suggest that eTregs are not just expanded but transformed cells with enhanced capacities of immune suppression. Our findings may influence further development of cell immunosuppressive therapy based on regulatory T cells.

scholarly journals Compared Phenolic Compound Contents of 22 Commercial Fruit and Vegetable Juices: Relationship to Ex-Vivo Vascular Reactivity and Potential In Vivo Projection

Antioxidants ◽  
2020 ◽  
Vol 9 (2) ◽  
pp. 92 ◽  
Author(s):  
Alexis Matute ◽  
Jessica Tabart ◽  
Jean-Paul Cheramy-Bien ◽  
Bernard Pirotte ◽  
Claire Kevers ◽  
...  
Keyword(s):  
Phenolic Compounds ◽  
Phenolic Compound ◽  
Vascular Reactivity ◽  
Ex Vivo ◽  
Clinical Investigation ◽  
Epigallocatechin Gallate ◽  
Fruit Juices ◽  
Organ Bath ◽  
Total Polyphenol ◽  
Total Anthocyanin

The real impact of polyphenol-rich vegetable and fruit juice intake on cardiovascular health remains a matter of controversy. In the present study, rat aorta segments immersed in an organ bath (OB) were used to explore whether the total polyphenol content and/or individual phenolic compound contents of 22 commercial vegetable (n = 3) and fruit juices [(citrus (n = 5), berries (n = 10), apple (n = 2), pineapple (n = 2)] might be associated with vascular tone. Red juices (particularly blackcurrant) and lemon juice caused the most marked vasorelaxation, its amplitude being endothelium dependent or not according to the volume ratio of juice to initial OB solution Vjuice/VOBS). At volume ratios 5% and 10%, both the juice and OB total polyphenol for all juices and total anthocyanin contents for berry juices significantly correlated with aorta vasorelaxation intensity. This was not the case for total or individual flavonols (except kaempferol) or for total or individual flavanols (except epigallocatechin gallate). If one relates our measured concentrations of individual phenolic compounds in OB to what is known about their physiological concentrations, and given our evidenced correlations between compound concentrations and vasorelaxation intensity, kaempferol, epigallocatechin gallate and peonidin-3-O-glucoside seem to emerge as the interesting phenolic compounds likely to be responsible for the potent vasorelaxation observed with fruit juices, and more particularly blackcurrant ones. Clinical investigation is required, however, to confirm our observations.

scholarly journals Biohydrogel Based on Dynamic Covalent Bonds for Wound Healing Applications

2021 ◽  
Vol 11 (15) ◽  
pp. 6945
Author(s):  
Chukwuma O. Agubata ◽  
Cynthia C. Mbaoji ◽  
Ifeanyi T. Nzekwe ◽  
César Saldías ◽  
David Díaz Díaz
Keyword(s):  
Wound Healing ◽  
Interfacial Tension ◽  
Blood Clotting ◽  
Phenylboronic Acid ◽  
Moisture Loss ◽  
Self Healing ◽  
Covalent Bonds ◽  
Treatment Groups ◽  
Acid Soluble Collagen ◽  
Thixotropic Behavior

In this work, a biohydrogel based on alginate and dynamic covalent B-O bonds, and derived composites, has been evaluated for wound healing applications. In particular, a phenylboronic acid–alginate (PBA-Alg) complex was synthesized by coupling 3-aminophenylboronic acid onto alginate, and used to prepare varied concentrations of hydrogels and silicate-based nanocomposites in PBS. The resulting hydrogels were characterized in terms of interfacial tension, moisture uptake and loss, interaction with fresh acid-soluble collagen, self-healing ability, effects on blood clotting and wound healing. The interfacial tension between the hydrogels and biorelevant fluids was low and moisture loss of 55%–60% was evident without uptake from the environment. The components of the hydrogels and their mixtures with collagen were found to be compatible. These hydrogels showed efficient self-healing and thixotropic behavior, and the animals in the treatment groups displayed blood clotting times between 9.1 min and 10.7 min. In contrast, the composites showed much longer or shorter clotting times depending on the silicate content. A significant improvement in wound healing was observed in 3% w/v PBA-Alg formulations. Overall, the PBA-Alg hydrogels exhibit self-healing dynamic covalent interactions and may be useful in dressings for incision wounds.

scholarly journals Irreversible and Self-Healing Electrically Conductive Hydrogels Made of Bio-Based Polymers

2022 ◽  
Vol 23 (2) ◽  
pp. 842
Author(s):  
Ahmed Ali Nada ◽  
Anita Eckstein Andicsová ◽  
Jaroslav Mosnáček
Keyword(s):  
Renewable Resources ◽  
Mechanical Stability ◽  
Conductive Polymers ◽  
Special Focus ◽  
Self Healing ◽  
Natural Polymers ◽  
Electrically Conductive ◽  
Preparation Methods ◽  
Cross Links ◽  
Conductive Hydrogels

Electrically conductive materials that are fabricated based on natural polymers have seen significant interest in numerous applications, especially when advanced properties such as self-healing are introduced. In this article review, the hydrogels that are based on natural polymers containing electrically conductive medium were covered, while both irreversible and reversible cross-links are presented. Among the conductive media, a special focus was put on conductive polymers, such as polyaniline, polypyrrole, polyacetylene, and polythiophenes, which can be potentially synthesized from renewable resources. Preparation methods of the conductive irreversible hydrogels that are based on these conductive polymers were reported observing their electrical conductivity values by Siemens per centimeter (S/cm). Additionally, the self-healing systems that were already applied or applicable in electrically conductive hydrogels that are based on natural polymers were presented and classified based on non-covalent or covalent cross-links. The real-time healing, mechanical stability, and electrically conductive values were highlighted.

Self-Healing Polymers Based on Reversible Covalent Bonds

2015 ◽  
pp. 1-58 ◽  
Author(s):  
Natascha Kuhl ◽  
Stefan Bode ◽  
Martin D. Hager ◽  
Ulrich S. Schubert
Keyword(s):  
Self Healing ◽  
Covalent Bonds ◽  
Reversible Covalent

scholarly journals Conductive, Stretchable, and Self-healing Ionic Gel Based on Dynamic Covalent Bonds and Electrostatic Interaction

2019 ◽  
Vol 37 (11) ◽  
pp. 1053-1059 ◽  
Author(s):  
Yi Sun ◽  
Yong-Yuan Ren ◽  
Qi Li ◽  
Rong-Wei Shi ◽  
Yin Hu ◽  
...  
Keyword(s):  
Electrostatic Interaction ◽  
Self Healing ◽  
Covalent Bonds
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