Cage-like Proteins as Bioink Components for 3D Bioprinting

Abstract

Hydrogel matrices have been used as structural surrogates in 3D bioprinting as a mechanism to provide the appropriate environment for cell adhesion and proliferation. In this research, the preparation and optimization of a hydrogel bioink containing a cage protein was investigated; specifically a Horse Spleen Ferritin (HSF)-poly (ethyleneglycol) diacrylate (PEGDA)-based bioink was developed. Studies were also undertaken to optimize the formulation of these bioinks for use in 3D bioprinting strategies, to develop techniques to precisely deposit cage proteins in hydrogels while maintaining their quaternary protein structures. In addition, the rheological properties of these various bioinks were evaluated. Finally, an optimized set of hydrogels was studied with respect to their effects on the growth of E. coli expressing a green fluorescent protein variant (His-tag GFP-S65T). Confocal microscopy experiments employed the presence of the bacterially expressed GFP fluorescence to follow bacterial cell migration in bioprinted and casted hydrogel constructs. Evaluation of cell viability within these constructs was also determined. Results indicated that the system had good potential for fabricating hydrogel scaffolds with high accuracy, fidelity and resolution.