Tissue engineering is an emergent discipline which has the aim to elaborate bioartificial tissues or functional substitutes through the rational combination of biomaterials, cells, and growth factors. For years, these bioartificial tissues were elaborated by using adult differentiated cells obtained from healthy biopsies. However, most of these cells are difficult to isolate, showed slow ex vivo expansion, and lose their phenotype and genotype or even worse; some cells are not always available or their use is clinically limited. In this regard, stem cells emerged as a promising cell source for the elaboration of different kinds of bioartificial tissues by tissue engineering. Depending on the linage of these stem cells, they showed an acceptable expansion capability, they are cryopreservable, they can modulate the host immune response, and, finally, under the correct stimuli, they have the extraordinary capability to differentiate into other cells linages by changing their genotype and phenotype. However, much still needs to be elucidated in order to be able to create efficient and safe bioartificial substitutes for clinical use.

We invite researchers to contribute original research articles and reviews focused on the use of different kinds of stem cells as base for the fabrication of three-dimensional (3D) bioartificial substitutes for future clinical applications. Ex vivo studies must be focused on in the design and characterization of these novel stem cells-based 3D substitutes, with special interest in the stem cell behavior and cell-biomaterials interactions. In the case of the in vivo studies, they should address the in vivo regeneration capability of the stem cells or stem cells-based 3D substitutes. In addition, a particular interest will be given to studies exploring or discussing the possible role and fate of the stem cells in vivo, as well their advantage, disadvantage, or even negative ex vivo or in vivo results.

Potential topics include but are not limited to the following:

• Biomaterials for 3D culture and differentiation of stem cells
• Bioprinting technologies and stem cells
• Stem cells-based scaffold-free tissue models
• Impact of biomaterials structure and composition on stem cell behavior and differentiation
• In vivo evaluation of stem cells behavior, fate, and host response
• In vivo evaluation of tissue regeneration by using stem cells-based 3D substitutes
• In vivo transplantation strategies for stem cells or stem cells-based 3D substitutes