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With the advancement in 3D bioprinting technology, cell culture methods can design 3D environments which are both, complex and physiologically relevant. The main component in 3D bioprinting, bioink, can be split into various categories depending on the criterion of categorization. Although the choice of bioink and bioprinting process will vary greatly depending on the application, general features such as material properties, biological interaction, gelation, and viscosity are always important to consider. The foundation of 3D bioprinting is the exact layer-by-layer implantation of biological elements, biochemicals, and living cells with the spatial control of the implantation of functional elements onto the biofabricated 3D structure. Three basic strategies underlie the 3D bioprinting process: autonomous self-assembly, micro tissue building blocks, and biomimicry or biomimetics. Tissue engineering can benefit from 3D bioprinting in many ways, but there are still numerous obstacles to overcome before functional tissues can be produced and used in clinical settings. A better comprehension of the physiological characteristics of bioink materials and a higher level of ability to reproduce the intricate biologically mimicked and physiologically relevant 3D structures would be a significant improvement for 3D bioprinting to overcome the limitations., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

3-D Bioprinting is employed as a novel approach in biofabrication to promote skin regeneration following chronic-wounds and injury. A novel bioink composed of carbohydrazide crosslinked {polyethylene oxide-co- Chitosan-co- poly(methylmethacrylic-acid)} (PEO-CS-PMMA) laden with Nicotinamide and human dermal fibroblast was successfully synthesized via Free radical-copolymerization at 73 °C. The developed bioink was characterized in term of swelling, structural-confirmation by solid state 13C-Nuclear Magnetic Resonance (NMR), morphology, thermal, 3-D Bioprinting via extrusion, rheological and interaction with DNA respectively. The predominant rate of gelation was attributed to the electrostatic interactions between cationic CS and anionic PMMA pendant groups. The morphology of developed bioink presented a porous architecture satisfying the cell and growth-factor viability across the barrier. The thermal analysis revealed two-step degradation with 85 % weight loss in term of decomposition and molecular changes in the bioink moieties By applying low pressure in the range of 25-50 kPa, the optimum reproducibility and printability were determined at 37 °C in the viscosity range of 500-550 Pa. s. A higher survival rate of 92 % was observed for (PEO-CS-PMMA) in comparison to 67 % for pure chitosan built bioink. A binding constant of K ≈ 1.8 × 10 6  M -1 recognized a thermodynamically stable interaction of (PEO-CS-PMMA) with the Salmon-DNA. Further, the addition of PEO (5.0 %) was addressed with better self-healing and printability to produce skin-tissue constructs to replace the infected skin in human., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

A series of sulfonyl hydrazones derived from 3-formylchromone was synthesized and discovered to be effective, non-selective inhibitors of monoamine oxidases (MAO-A and MAO-B). The compounds are easily (synthetically) accessible in high yields, by simple condensation of 4-methylbenzenesulfonohydrazide with different (un)substituted 3-formylchromones. All compounds had IC 50 values in lower micro-molar range (IC 50  = 0.33-7.14 μM for MAO-A, and 1.12-3.56 μM for MAO-B). The most active MAO-B inhibitor was N'-[(E)-(6-fluoro-4-oxo-4H-chromen-3-yl)methylidene]-4-methylbenzenesulfonohydrazide (3e) with IC 50 value of 1.12 ± 0.02 μM, and N'-[(E)-(6-chloro-4-oxo-4H-chromen-3-yl)methylidene]-4-methylbenzenesulfonohydrazide (3f) was the most active MAO-A inhibitor with IC 50 value of 0.33 ± 0.01 μM. From enzyme kinetic studies, the mode of inhibition against MAO-B was found to be competitive, whereas against MAO-A, it was found to be non-competitive. Molecular docking studies indicated a new binding pocket for non-competitive MAO-A inhibitors. The activity of these compounds is optimally combined with highly favorable ADME profile with predicted good oral bioavailability., (Copyright © 2017 Elsevier Inc. All rights reserved.)