Rosettes & Ribbons: Some Recent Accomplishments of Note at the School

Developing a simple produces for efficient derivation of motor neurons (MNs) is essential for neural tissue engineering studies. Stem cells with high capacity for neural differentiation and scaffolds with the potential to promote motor neurons differentiation are promising candidates for neural tissue engineering. Recently, human olfactory ecto-mesenchymal stem cells (OE-MSCs), which are isolated easily from the olfactory mucosa, are considered a new hope for neuronal replacement due to their neural crest origin. Herein, we synthesized conducting hydrogels using different concentration of chitosan-g-aniline pentamer, gelatin, and agarose. The chemical structures, swelling and deswelling ratio, ionic conductivity and thermal properties of the hydrogel were characterized. Scaffolds with 10 chitosan-g-aniline pentamer/gelatin (S10) were chosen for further investigation and the potential of OE-MSCs as a new source for programming to motor neuron-like cells investigated on tissue culture plate (TCP) and conductive hydrogels. Cell differentiation was evaluated at the level of mRNA and protein synthesis and indicated that conductive hydrogels significantly increased the markers related to motor neurons including Hb-9, Islet-1 and ChAT compared to TCP. Taken together, the results suggest that OE-MSCs would be successfully differentiated into motor neuron-like cells on conductive hydrogels and would have a promising potential for treating motor neuron-related diseases. © 201

Corrigendum to �Ultrahigh-water-content biocompatible gelatin-based hydrogels: Toughened through micro-sized dissipative morphology as an effective strategy� Mater. Sci. Eng. C 120 (2021) 111750(S0928493120336699)(10.1016/j.msec.2020.111750)

The authors regret to have made a mistake on their published article in one of the affiliations as well as corresponding authors details. The correct affiliation â��aâ�� should be a Polymer Chemistry Research Laboratory, Department of Chemistry, University of Isfahan, Isfahan 81746-73441, Islamic Republic of Iran. And the corresponding author details should be: Corresponding authors at: a Polymer Chemistry Research Laboratory, Department of Chemistry, University of Isfahan, Isfahan 81746-73441, Islamic Republic of Iran. b MERLN Institute for Technology Inspired Regenerative Medicine, Complex Tissue Regeneration Department, Maastricht University, Universiteitssingel 40, 6229ER Maastricht, the Netherlands. E-mail addresses: [email protected] (F. Rafiemanzelat), [email protected] (L. Moroni). The authors would like to apologise for any inconvenience caused. © 202

Ultrahigh-water-content biocompatible gelatin-based hydrogels: Toughened through micro-sized dissipative morphology as an effective strategy

Fabrication of simultaneously robust and superabsorbent gelatin-based hydrogels for biomedical applications still remains a challenge due to lack of locally dissipative points in the presence of large water content. Here, we apply a synthesis strategy through which water absorbency and energy dissipative points are separated, and toughening mechanism is active closely at the crack tip. For this, gelatin-based microgels (GeMs) were synthesized in a way that concentrated supramolecular interactions were present to increase the energy necessary to propagate a macroscopic crack. The microgels were interlocked to each other via both temporary hydrophobic associations and permanent covalent crosslinks, in which the sacrificial binds sustained the toughness due to the mobility of the junction zones and particles sliding. However, chemical crosslinking points preserved the integrity and fast recoverability of the hydrogel. Hysteresis increased strongly with increasing supramolecular interactions within the network. The prepared hydrogels showed energy loss and swelling ratio up to 3440 J. m�3 and 830, respectively, which was not achievable with conventional network fabrication methods. The microgels were also assessed for their in vivo biocompatibility in a rat subcutaneous pocket assay. Results of hematoxylin and eosin (H&E) staining demonstrated regeneration of the tissue around the scaffolds without incorporation of growth factors. Also, vascularization within the scaffolds was observed after 4 weeks implantation. These results indicate that our strategy is a promising method to manipulate those valuable polymers, which lose their toughness and applicability with increasing their water content. © 202

3D printing of jammed self-supporting microgels with alternative mechanism for shape fidelity, crosslinking and conductivity

Additive manufacturing technology is a growing field, which demands advanced chemistry and fabrication process if smart-materials are desired. Herein, the concept of jammed microgels designed with a new crosslinking method is introduced to be used in 3D-printing applications. Jammed microgels decorated with superficial hydrophobic segments and pure thermo-sensitive gelatin are applied as inks and exhibit shear-induced transition and fast recoverability, which are important for 3D-printing. The interaction of microgels within the as-extruded filaments and with the adjacent deposited layers guarantees shape-fidelity. After printing, a deep eutectic solvent (DES) formed from Arginine and Glycerol ([DES] Arg/Gly) is applied over the construct to trigger a chemical crosslinking reaction between epoxy and amine groups. The introduced [DES] Arg/Gly can play simultaneously two roles: (1) activator of covalent bond formation and (2) conducting agent. Generally, a variety of features including printability, rheological properties and shape-retention are dependent on the fraction of hydrophobic segments and the applied [DES] Arg/Gly concentration. Further, the main network percolation reaction follows a different strategy to achieve a sustainable printable system with biological, mechanical and physiological sustainability of the construct. These results open new possibilities to fabricate a wide range of adaptive platforms of smart materials with ease

3D printing of jammed self-supporting microgels with alternative mechanism for shape fidelity, crosslinking and conductivity

Additive manufacturing technology is a growing field, which demands advanced chemistry and fabrication process if smart-materials are desired. Herein, the concept of jammed microgels designed with a new crosslinking method is introduced to be used in 3D-printing applications. Jammed microgels decorated with superficial hydrophobic segments and pure thermo-sensitive gelatin are applied as inks and exhibit shear-induced transition and fast recoverability, which are important for 3D-printing. The interaction of microgels within the as-extruded filaments and with the adjacent deposited layers guarantees shape-fidelity. After printing, a deep eutectic solvent (DES) formed from Arginine and Glycerol ([DES] Arg/Gly) is applied over the construct to trigger a chemical crosslinking reaction between epoxy and amine groups. The introduced [DES] Arg/Gly can play simultaneously two roles: (1) activator of covalent bond formation and (2) conducting agent. Generally, a variety of features including printability, rheological properties and shape-retention are dependent on the fraction of hydrophobic segments and the applied [DES] Arg/Gly concentration. Further, the main network percolation reaction follows a different strategy to achieve a sustainable printable system with biological, mechanical and physiological sustainability of the construct. These results open new possibilities to fabricate a wide range of adaptive platforms of smart materials with ease

Chondrogenesis of human adipose-derived mesenchymal stromal cells on the devitalized costal cartilage matrix/poly(vinyl alcohol)/fibrin hybrid scaffolds

Porous scaffolds derived from native cartilage matrix along with autologous cells could be an effective tool for cartilage tissue engineering (CTE). Recently, it was shown that scaffolds based on cartilage extra cellular matrix (ECM) can induce chondrogenesis of human adipose-derived mesenchymal stromal cells (ASCs) without using exogenous growth factors. However, lack of mechanical properties, rapid biodegradation, and contraction of these scaffolds in culture limit further applications. The present study investigated the fabrication of novel scaffolds based on devitalized costal cartilage matrix (DCM) and poly vinyl alcohol (PVA), using genipin as a natural crosslinker. For this purpose, PVA was modified to expose amine groups (PVA-A), which crosslinked with DCM powder via the lowest genipin percentage of 0.04 (wt/wt). The crosslinked scaffolds were characterized by different techniques including porosity percentage, pore size, mechanical properties, crosslinking density, and swelling. ASCs were seeded on the scaffolds using fibrin hydrogel. Gene expression measurements, biochemical assays and histological staining confirmed that ASC-seeded constructs cultured in the chondrogenic medium can express cartilage-specific genes and synthesize cartilage-related macromolecules. In the presence of TGF-β3 the constructs exhibited significant expression of these markers compared to the control medium. These findings suggest that genipin-crosslinked DCM-PVA-A/ fibrin can be considered as an appealing hybrid scaffold for CTE applications. © 2019 Elsevier Lt

Fabrication of chitosan/agarose scaffolds containing extracellular matrix for tissue engineering applications

One of the most effective approaches for treatment of cartilage involves the use of porous three-dimensional scaffolds, which are useful for improving not only cellular adhesion but also mechanical properties of the treated tissues. In this study, we manufactured a composite scaffold with optimum properties to imitate nasal cartilage attributes. Cartilage extracellular matrix (ECM) was used in order to improve the cellular properties of the scaffolds; while, chitosan and agarose were main materials that are used to boost the mechanical and rheological properties of the scaffolds. Furthermore, we explored the effect of the various weight ratios of chitosan, agarose, and ECM on the mechanical and biomedical properties of the composite scaffolds using the Taguchi method. The resulting composites display a range of advantages, including good mechanical strength, porous morphology, partial crystallinity, high swelling ratio, controlled biodegradability rate, and rheological characteristics. Additionally, we performed the cytotoxicity tests to confirm the improvement of the structure and better cell attachments on the scaffolds. Our findings illustrate that the presence of the ECM in chitosan/agarose structure improves the biomedical characteristics of the final scaffold. In addition, we were able to control the mechanical properties and microstructure of the scaffolds by optimizing the polymers' concentration and their resulting interactions. These results present a novel scaffold with simultaneously enhanced mechanical and cellular attributes comparing to the scaffolds without ECM for nasal cartilage tissue engineering applications. © 201