Hybrid GelMA-Turnip mosaic virus(TuMV) scaffolds for enhanced fibroblast proliferation: Effect of EGF conjugation on the TuMV surface

Tissue Engineering promises to deliver real solutions in several relevant fronts of modern medicine including regenerative medicine, pharmacological screening, and fundamental biomedical research. Modern tissue engineering techniques rely heavily in the use of hydrogels to support cell proliferation in 2D and 3D cultures. Often, these need functionalization with signaling molecules or biological factors to promote cell proliferation, differentiation and viability. Growth factors (GFs) are naturally occurring proteins that stimulate cellular growth, proliferation and differentiation. However, GFs translation into clinical applications is limited due to their short effective half-life, low stability, and rapid inactivation by enzymes under physiological conditions. Protein immobilization techniques combined with nanomaterial carriers have shown promise in augmenting the delivery, stability and effectiveness of GFs. Viral nanoparticles have uniform and well-defined nano-structures and can be produced in large quantities. Several protein based systems such as plant viral nanoparticles have been tested in biomedical applications due to their biosafety, biocompatibility, and surface modification availability. In this work, we propose the development of smart-tailored hydrogels: Gelatin methacryloyl (GelMA) with a nanoscaffold of Turnip mosaic virus(TuMV) functionalized with Epidermal Growth Factor (EGF) for sustained release of the growth factor to cells in 2D and 3D cultures. EGF-conjugated nanostructured hydrogel samples promoted at least a 30\% increase in cell proliferation, viability and attachment compared to unbound EGF, at equivalent concentrations in 2D and 3D cultures. This validates TuMV as an immobilization platform for multimeric conjugation of the growth factor. Combined with GelMA, they provide a two-way immobilization system for EGF, augmenting its stability and exposition to the cells.