Systematic optimization of visible light-induced crosslinking conditions of gelatin methacryloyl (GelMA)

AbstractGelatin methacryloyl (GelMA) is one of the most widely used photo-crosslinkable biopolymers in tissue engineering. In in presence of an appropriate photoinitiator, the light activation triggers the crosslinking process, which provides shape fidelity and stability at physiological temperature. Although ultraviolet (UV) has been extensively explored for photo-crosslinking, its application has been linked to numerous biosafety concerns, originated from UV phototoxicity. Eosin Y, in combination with TEOA and VC, is a biosafe photoinitiation system that can be activated via visible light instead of UV and bypasses those biosafety concerns; however, the crosslinking system needs fine-tuning and optimization. In order to systematically optimize the crosslinking conditions, we herein independently varied the concentrations of Eosin Y [(EY)], triethanolamine (TEOA), vinyl caprolactam (VC), GelMA precursor, and crosslinking times and assessed the effect of those parameters on the properties the hydrogel. Our data showed that except EY, which exhibited an optimal concentration (~ 0.05 mM), increasing [TEOA], [VA], [GelMA], or crosslinking time improved mechanical (tensile strength/modulus and compressive modulus), adhesion (lap shear strength), swelling, biodegradation properties of the hydrogel. However, increasing the concentrations of crosslinking reagents ([TEOA], [VA], [GelMA]) reduced cell viability in 3-dimensional (3D) cell culture. This study enabled us to optimize the crosslinking conditions to improve the properties of the GelMA hydrogel and to generate a library of hydrogels with defined properties essential for different biomedical applications.

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Rhodamines as Photocatalyst in Organic Synthesis

Current Green Chemistry ◽

10.2174/2213346107999201026201232 ◽

2020 ◽

Vol 07 ◽

Author(s):

Avik K. Bagdi ◽

Papiya Sikdar

Keyword(s):

Visible Light ◽

Organic Synthesis ◽

Organic Dyes ◽

Transition Metal Catalysts ◽

Visible Light Photocatalysis ◽

Eosin Y ◽

Organic Transformations ◽

The Sustainable Development ◽

Mechanistic Pathway ◽

Green Model

Abstract:: Organic synthesis under environment friendly conditions has great impact in the sustainable development. In this context, visible light photocatalysis has emerged as a green model as this offers an energy-efficient pathway towards the organic transformation. Different transition-metal catalysts (Ir-, Ru-, Cu- etc) and organic dyes (eosin Y, rose bengal, methylene blue etc) are well-known photocatalysts in organic synthesis. Apart from the well-known organophotoredox catalysts, rhodamines (Rhodamine B and Rhodamine 6G) have been also employed as efficient photocatalysts for different organic transformations. In this review, we will focus on the photocatalysis by rhodamines in organic synthesis. Mechanistic pathway of the methodologies will also be discussed. We believe this review will stimulate the employment of rhodamines in the visible light photocatalysis for efficient organic transformations in the future.

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Highly chemoselective deoxygenation of N-heterocyclic N-oxides under transition metal-free conditions

Organic & Biomolecular Chemistry ◽

10.1039/d1ob00260k ◽

2021 ◽

Vol 19 (16) ◽

pp. 3735-3742

Author(s):

Se Hyun Kim ◽

Ju Hyeon An ◽

Jun Hee Lee

Keyword(s):

Transition Metal ◽

Visible Light ◽

Eosin Y ◽

Metal Free ◽

Simple Protocol

Here, we provide an operationally simple protocol for the highly chemoselective deoxygenation of various functionalized N-heterocyclic N-oxides under visible light-mediated photoredox conditions with Na2-eosin Y as an organophotocatalyst.

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Comparative Study of Silk Fibroin-Based Hydrogels and Their Potential as Material for 3-Dimensional (3D) Printing

Molecules ◽

10.3390/molecules26133887 ◽

2021 ◽

Vol 26 (13) ◽

pp. 3887

Author(s):

Watcharapong Pudkon ◽

Chavee Laomeephol ◽

Siriporn Damrongsakkul ◽

Sorada Kanokpanont ◽

Juthamas Ratanavaraporn

Keyword(s):

3D Printing ◽

Silk Fibroin ◽

Biomedical Applications ◽

Mechanical Stability ◽

Three Dimensional ◽

Structure Stability ◽

3 Dimensional ◽

Critical Technology ◽

Box Structure ◽

High Degree

Three-dimensional (3D) printing is regarded as a critical technology in material engineering for biomedical applications. From a previous report, silk fibroin (SF) has been used as a biomaterial for tissue engineering due to its biocompatibility, biodegradability, non-toxicity and robust mechanical properties which provide a potential as material for 3D-printing. In this study, SF-based hydrogels with different formulations and SF concentrations (1–3%wt) were prepared by natural gelation (SF/self-gelled), sodium tetradecyl sulfate-induced (SF/STS) and dimyristoyl glycerophosphorylglycerol-induced (SF/DMPG). From the results, 2%wt SF-based (2SF) hydrogels showed suitable properties for extrusion, such as storage modulus, shear-thinning behavior and degree of structure recovery. The 4-layer box structure of all 2SF-based hydrogel formulations could be printed without structural collapse. In addition, the mechanical stability of printed structures after three-step post-treatment was investigated. The printed structure of 2SF/STS and 2SF/DMPG hydrogels exhibited high stability with high degree of structure recovery as 70.4% and 53.7%, respectively, compared to 2SF/self-gelled construct as 38.9%. The 2SF/STS and 2SF/DMPG hydrogels showed a great potential to use as material for 3D-printing due to its rheological properties, printability and structure stability.

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Effect of tungsten disulfide nanotubes on crystallization of polylactide under uniaxial deformation and annealing

Functional Composite Materials ◽

10.1186/s42252-021-00016-2 ◽

2021 ◽

Vol 2 (1) ◽

Author(s):

Fausta Loffredo ◽

Loredana Tammaro ◽

Tiziana Di Luccio ◽

Carmela Borriello ◽

Fulvia Villani ◽

...

Keyword(s):

Biomedical Applications ◽

Structural Evolution ◽

Tungsten Disulfide ◽

Fine Tuning ◽

Nanocomposite Films ◽

Uniaxial Deformation ◽

Scanning Calorimetry ◽

X Ray ◽

X Ray Scattering

AbstractTungsten disulfide (WS2) nanotubes (NTs) are examined here as a filler for polylactide (PLA) for their ability to accelerate PLA crystallization and for their promising biocompatibility in relevant to biomedical applications of PLA-WS2 nanocomposites. In this work, we have studied the structural and thermal properties of PLA-WS2 nanocomposite films varying the concentration of WS2 NTs from 0 (neat PLA) to 0.6 wt%. The films were uniaxially drawn at 90 °C and annealed at the same temperature for 3 and 10 min. Using wide angle x-ray scattering, Raman spectroscopy and differential scanning calorimetry, we probed the effects of WS2 NT addition on the structure of the PLA films at various stages of processing (unstretched, stretching, annealing). We found that 0.6 wt% of WS2 induces the same level of crystallinity in as stretched PLA-WS2 as annealing in neat PLA for 10 min. These data provide useful insights into the role of WS2 NTs on the structural evolution of PLA-WS2 composites under uniaxial deformation, and extend their applicability to situations where fine tuning of PLA crystallinity is desirable.

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Biofabrication of Cell-Laden Gelatin Methacryloyl Hydrogels with Incorporation of Silanized Hydroxyapatite by Visible Light Projection

Polymers ◽

10.3390/polym13142354 ◽

2021 ◽

Vol 13 (14) ◽

pp. 2354

Author(s):

Jimmy Jiun-Ming Su ◽

Chih-Hsin Lin ◽

Hsuan Chen ◽

Shyh-Yuan Lee ◽

Yuan-Min Lin

Keyword(s):

Mechanical Properties ◽

Visible Light ◽

3D Structure ◽

Three Dimensional ◽

3D Cell Culture ◽

Composite Hydrogel ◽

Digital Light Processing ◽

Mg63 Cells ◽

Marrow Mesenchymal Stem Cells ◽

Low Cytotoxicity

Gelatin methacryloyl (GelMA) hydrogel is a photopolymerizable biomaterial widely used for three-dimensional (3D) cell culture due to its high biocompatibility. However, the drawback of GelMA hydrogel is its poor mechanical properties, which may compromise the feasibility of biofabrication techniques. In this study, a cell-laden GelMA composite hydrogel with a combination incorporating silanized hydroxyapatite (Si-HAp) and a simple and harmless visible light crosslinking system for this hydrogel were developed. The incorporation of Si-HAp into the GelMA hydrogel enhanced the mechanical properties of the composite hydrogel. Moreover, the composite hydrogel exhibited low cytotoxicity and promoted the osteogenic gene expression of embedded MG63 cells and Human bone marrow mesenchymal stem cells (hBMSCs). We also established a maskless lithographic method to fabricate a defined 3D structure under visible light by using a digital light processing projector, and the incorporation of Si-HAp increased the resolution of photolithographic hydrogels. The GelMA-Si-HAp composite hydrogel system can serve as an effective biomaterial in bone regeneration.

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Visible-Light-Mediated Synthesis of Substituted Phenazine and Phenoxazinone Using Eosin Y as a Photoredox Catalyst

Organic Letters ◽

10.1021/acs.orglett.1c00725 ◽

2021 ◽

Author(s):

Ashish Kumar Dhara ◽

Sayantan Maity ◽

Basab Bijayi Dhar

Keyword(s):

Visible Light ◽

Eosin Y

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Visible light activation of superhydrophobic BiOBr/Ag loaded copper mesh for degradation and their use in oil/water separation

Journal of the Taiwan Institute of Chemical Engineers ◽

10.1016/j.jtice.2019.06.007 ◽

2019 ◽

Vol 102 ◽

pp. 233-241 ◽

Cited By ~ 11

Author(s):

Bo Ge ◽

Guina Ren ◽

Xiao Miao ◽

Xiuling Li ◽

Tingxiao Zhang ◽

...

Keyword(s):

Visible Light ◽

Light Activation ◽

Water Separation ◽

Oil Water Separation ◽

Oil Water ◽

Visible Light Activation ◽

Copper Mesh

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Eosin Y photoredox catalyzed net redox neutral reaction for regiospecific annulation to 3-sulfonylindoles via anion oxidation of sodium sulfinate salts

Organic & Biomolecular Chemistry ◽

10.1039/c7ob02977b ◽

2018 ◽

Vol 16 (4) ◽

pp. 536-540 ◽

Cited By ~ 15

Author(s):

Rajendra S. Rohokale ◽

Shrikant D. Tambe ◽

Umesh A. Kshirsagar

Keyword(s):

Visible Light ◽

Eosin Y ◽

Cascade Cyclization ◽

Neutral Reaction ◽

Neutral Process ◽

Radical Cascade

An eosin Y photoredox catalyzed net redox neutral process for 3-sulfonylindoles via the anionic oxidation of sodium sulfinate salts and its radical cascade cyclization with 2-alkynyl-azidoarenes was developed with visible light as a mediator.

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