Adaptable hydrogels have recently emerged as a promising platform for three-dimensional (3D) cell encapsulation and culture. In conventional, covalently crosslinked hydrogels, degradation is typically required to allow complex cellular functions to occur, leading to bulk material degradation. In contrast, adaptable hydrogels are formed by reversible crosslinks. Through breaking and re-formation of the reversible linkages, adaptable hydrogels can be locally modified to permit complex cellular functions while maintaining their long-term integrity. In addition, these adaptable materials can have biomimetic viscoelastic properties that make them well suited for several biotechnology and medical applications. In this review, an overview of adaptable-hydrogel design considerations and linkage selections is presented, with a focus on various cell-compatible crosslinking mechanisms that can be exploited to form adaptable hydrogels for tissue engineering.

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Adaptable Hydrogel Networks with Reversible Linkages for Tissue Engineering

The extracellular matrix and transforming growth factor-β1: Tale of a strained relationship

Three dimensional electrospun PCL/PLA blend nanofibrous scaffolds with significantly improved stem cells osteogenic differentiation and cranial bone formation

Somatic cells can be reprogrammed into induced pluripotent stem cells biochemically through the expression of a few transcription factors. It is now shown that aligned microgrooves or nanofibres on cell-adhesive substrates can promote the reprogramming of somatic cells more efficiently through epigenetic regulation of genes related to pluripotency and the mesenchymal-to-epithelial transition. The findings suggest that the epigenetic state can be regulated by variations in cell morphology.

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Biophysical regulation of epigenetic state and cell reprogramming

Hydrogels that mimic biological extracellular matrix (ECM) can provide cells with mechanical support and signaling cues to regulate their behavior. However, despite the ability of hydrogels to generate artificial ECM that can modulate cellular behavior, they often lack the mechanical strength needed for many tissue constructs. Here, we present reinforced CNT–gelatin methacrylate (GelMA) hybrid as a biocompatible, cell-responsive hydrogel platform for creating cell-laden three-dimensional (3D) constructs. The addition of carbon nanotubes (CNTs) successfully reinforced GelMA hydrogels without decreasing their porosity or inhibiting cell growth. The CNT–GelMA hybrids were also photopatternable allowing for easy fabrication of microscale structures without harsh processes. NIH-3T3 cells and human mesenchymal stem cells (hMSCs) readily spread and proliferated after encapsulation in CNT–GelMA hybrid microgels. By controlling the amount of CNTs incorporated into the GelMA hydrogel system, we demonstrated that th...

/pdf/carbon-nanotube-reinforced-hybrid-microgels-as-scaffold-1dnu90jg55.pdf

Carbon Nanotube Reinforced Hybrid Microgels as Scaffold Materials for Cell Encapsulation

The effect of matrix stiffness on the differentiation of mesenchymal stem cells in response to TGF-β.

Although the field of vascular tissue engineering has made tremendous advances in the past decade, several complications have yet to be overcome in order to produce biocompatible small-diameter vascular conduits with long-term patency. Stem cells and progenitor cells represent potential cell sources in the development of autologous (or allogeneic), nonthrombogenic vascular grafts with mechanical properties comparable to native blood vessel. However, a better understanding of the effects of mechanical forces on stem cells and progenitor cells is needed to properly utilize these cells for tissue engineering applications. In this chapter, we discuss the current understanding of the effects of hemodynamic forces on the differentiation and function of adult stem cells, embryonic stem cells, and progenitor cells. We also review the use of stem cells and progenitor cells in vascular graft engineering.

Rokhaya Diop

Papers

The effect of matrix stiffness on the differentiation of mesenchymal stem cells in response to TGF-β.

Effects of Hemodynamic Forces on the Vascular Differentiation of Stem Cells: Implications for Vascular Graft Engineering