3D printing biocompatible hydrogels

Due to their high water content, hydrogels are highly attractive biomaterials for 3D printing as efficient ‘surrogates’ for the extracellular matrix, onto which cells can be cultured. However, while they are relatively easy to produce using a method called extrusion printing, their stability and structural integrity can weaken when they’re in contact with biological fluids or extracellular matrices.

The Biomaterials for Regenerative Therapies group’s new method uses a hybrid bioink that doesn’t need any photochemical or organic reagent and which safe for use in vivo. Using a versatile and biocompatible method called sol-gel, this bioink can be used to print a peptide-functionalized hydrogel. It’s the first time sol-gel has been used for hydrogel inks, as all examples combining sol-gel and 3D printing have so far dealt either with inorganic constructs or with extrusion printing under non-biocompatible conditions.

The new matrices work better than current ones because, as well as being biocompatible, certain essential processes such as hydrolysis occur during the printing process, resulting in a much stronger and more reliable structure. The researchers, who worked in collaboration with colleagues in France, were able to successfully seed them with mesenchymal stem cells, and are now looking at the possibility of encapsulating cells within the hybrid ink so that seeding can take place during the construction process.

As well as producing a stronger matrix, the combination of sol-gel chemistry and 3D printing means that the new method could be a promising way to quickly produce an unlimited number of customized, cell-laden, biocompatible structures. Not only that, but using several different hybrid bioinks could open the way to making multilayer and non-homogeneous biomaterials, mimicking the complexity of natural tissues even more closely.

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Source article: C. Echalier, R. Levato, M. A. Mateos-Timoneda, O. Castaño, S. Déjean, X. Garric, C. Pinese, D. Noel, E. Engel, J. Martinez, A. Mehdi & G. Subra (2017). Modular bioink for 3D printing of biocompatible hydrogels: sol–gel polymerization of hybrid peptides and polymers. RSC Adv., 2017, 7, 12231

Fuente: Left: Fluorescent microscopy images of mouse mesenchymal stem cells after four days of culture on a hybrid 3D-printed scaffold