Carbon nanotube reinforced hybrid microgels as scaffold materials for cell encapsulation.

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 the mechanical properties of the hybrid material can be tuned making it suitable for various tissue engineering applications. Furthermore, due to the high pattern fidelity and resolution of CNT incorporated GelMA, it can be used for in vitro cell studies or fabricating complex 3D biomimetic tissue-like structures.