6.2 Hybridization of Thiol–Ene Chemistry Hydrogels for Biomedical Applications

2022 ◽  
Author(s):  
Z. Xu ◽  
K. M. Bratlie
Keyword(s):  
Free Radical ◽  
Biomedical Applications ◽  
Thiol Groups ◽  
Double Bonds ◽  
3D Scaffolds ◽  
Ene Reactions

AbstractLight-triggered thiol–ene polymerization is a powerful tool for synthesizing hydrogels that are aimed to be applied in situ or used as 3D scaffolds. Thiol–ene reactions are a class of click transformations that involve free-radical-mediated addition of electron-rich thiol groups to electron-poor carbon–carbon double bonds. When tuned with homopolymerization of the carbon–carbon double bonds, the resultant hydrogel properties can be finely adjusted. In this review, commonly used methods for modifying polymers with thiol groups or double bonds are discussed, and strategies to overcome flaws in thiol–ene hydrogels are provided. Emphasis is given to the application and outlook of thiol–ene cross-linked hydrogels.

A Strategy for Fabricating in Situ Topographical 3D Scaffolds Using 3D Printing and Pluronic F-127

2019 ◽  
Author(s):  
JiUn Lee ◽  
SooJung Chae ◽  
Hyeongjin Lee ◽  
GeunHyung Kim
Keyword(s):  
3D Printing ◽  
3D Scaffolds

Recent advances in Minisci-type reactions and applications in organic synthesis

2020 ◽  
Vol 24 ◽  
Author(s):  
Wengui Wang ◽  
Shoufeng Wang
Keyword(s):  
Free Radical ◽  
Hydrogen Atom ◽  
Organic Synthesis ◽  
Radical Reactivity ◽  
Atom Loss ◽  
Radical Generation ◽  
In Situ Generation ◽  
Thermal Cleavage ◽  
Synthetic Chemist

Abstract:: Minisci-type reactions have become widely known as reactions that involve the addition of carbon-centered radicals to basic heteroarenes followed by formal hydrogen atom loss. While the originally developed protocols for radical generation remain in active use today, in recent years by a new array of radical generation strategies allow use of a wider variety of radical precursors that often operate under milder and more benign conditions. New transformations based on free radical reactivity are now available to a synthetic chemist looking to utilize a Minisci-type reaction. Radical-generation methods based on photoredox catalysis and electrochemistry, which utilize thermal cleavage or the in situ generation of reactive radical precursors, have become popular approaches. Our review will cover the remarkably literature that has appeared on this topic in recent 5 years, from 2015-01 to 2020-01, in an attempt to provide guidance to the synthetic chemist, on both the challenges that have been overcome and applications in organic synthesis.

Anodic synthesis of TiO2 nanotubes by step-up voltages

2021 ◽  
pp. 002199832110237
Author(s):  
V Sivaprakash ◽  
R Narayanan
Keyword(s):  
Corrosion Resistance ◽  
Tio2 Nanotubes ◽  
Biomedical Applications ◽  
Phase Changes ◽  
Electrochemical Anodization ◽  
Corrosion Resistant ◽  
Anodization Process ◽  
Anodic Synthesis ◽  
Input Potential

Fabrication of TiO2 nanotubes (NTs) has extensive application properties due to their high corrosion resistant and compatibility with biomedical applications, the synthesis of TiO2 nanotubes over titanium has drawn interest in various fields. The synthesis of TiO2 NTs using novel in-situ step-up voltage conditions in the electrochemical anodization process is recorded in this work. For manufacturing the NTs at 1 hour of anodization, the input potential of 30, 40 and 50 V was selected. With increasing step-up voltage during the anodization process, an improvement in the NTs was observed, favoring corrosion resistance properties. The surface of NTs enhances the structure of the ribs, raising the potential for feedback over time. XRD was used to analyze phase changes, and HR-SEM analyzed surface topography. Impedance tests found that longer NTs improved the corrosion resistance.

scholarly journals Ultrafast self-gelling powder mediates robust wet adhesion to promote healing of gastrointestinal perforations

2021 ◽  
Vol 7 (23) ◽  
pp. eabe8739
Author(s):  
Xin Peng ◽  
Xianfeng Xia ◽  
Xiayi Xu ◽  
Xuefeng Yang ◽  
Boguang Yang ◽  
...  
Keyword(s):  
Biomedical Applications ◽  
Gastric Perforation ◽  
Interfacial Water ◽  
Wet Adhesion ◽  
Tissue Interactions ◽  
Tissue Surface ◽  
Strong Adhesion ◽  
Surface Irregularities ◽  
Physical Interactions

Achieving strong adhesion of bioadhesives on wet tissues remains a challenge and an acute clinical demand because of the interfering interfacial water and limited adhesive-tissue interactions. Here we report a self-gelling and adhesive polyethyleneimine and polyacrylic acid (PEI/PAA) powder, which can absorb interfacial water to form a physically cross-linked hydrogel in situ within 2 seconds due to strong physical interactions between the polymers. Furthermore, the physically cross-linked polymers can diffuse into the substrate polymeric network to enhance wet adhesion. Superficial deposition of PEI/PAA powder can effectively seal damaged porcine stomach and intestine despite excessive mechanical challenges and tissue surface irregularities. We further demonstrate PEI/PAA powder as an effective sealant to enhance the treatment outcomes of gastric perforation in a rat model. The strong wet adhesion, excellent cytocompatibility, adaptability to fit complex sites, and easy synthesis of PEI/PAA powder make it a promising bioadhesive for numerous biomedical applications.

CLINICAL APPLICATIONS OF ELECTROCHEMOTHERAPY

2019 ◽  
Author(s):  
Gregor Serša
Keyword(s):  
Biomedical Applications ◽  
Liver Tumors ◽  
Checkpoint Inhibitors ◽  
Combined Treatment ◽  
Local Treatment ◽  
Industrial Applications ◽  
Interleukin 12 ◽  
Nice Guidelines ◽  
Or Gene

Electroporation has several biomedical and industrial applications. The biomedical applications are in the field of drug or gene delivery. Electrochemotherapy utilizes electroporation for the increased delivery of cytotoxic drugs like bleomycin or cisplatin into tumors. The use of electrochemotherapy has spread throughout Europe for the treatment of cutaneous tumors or metastases. It is in the NICE guidelines and is becoming standard ablative technique in treatment of cancer. The technological advancements have also enabled the use of electrochemotherapy for the treatment of deep seated tumors, such as soft tissue or liver tumors. Clinical studies demonstrate good effectiveness on fibrosarcomas, colorectal liver metastases and hepatocellular carcinoma. However, electrochemotherapy is a local treatment that also induces moderate local immune response. This so called “in situ vaccination” induced by electrochemotherapy can be exploited in combined treatment with immune checkpoint inhibitors or electrogene therapy with immunostimulating effect. Therefore, gene electrotransfer of plasmid coding for interleukin 12 (IL-12), in combination with electrochemotherapy could result in transformation of electrochemotherapy from local into systemic treatment. This is also of our current interest, and we are undertaking steps to bring this idea from preclinical into clinical testing.

Effect of cell geometry on the in situ measurement of e.s.r.-free radical concentrations during pyrolysis of a ZnCl2-impregnated coal

Fuel ◽  
1988 ◽  
Vol 67 (9) ◽  
pp. 1249-1254 ◽  
Author(s):  
Timothy G. Fowler ◽  
Keith D. Bartle ◽  
Rafael Kandiyoti
Keyword(s):  
Free Radical ◽  
In Situ Measurement ◽  
Cell Geometry
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