Materials have been widely used in many Tissue Engineering (TE) solutions, as a structural support for adherent cells and as a vehicle to provide relevant biochemical and biophysical signals to control cell behavior. Different types of natural-based macromolecular materials have been proposed to prepare scaffolds for TE, including porous structures, hydrogels or microparticles. We have been proposing the use of human-derived proteins that, upon chemical modification, could be used to generate adequate microenvironments to interact adequately with cells. We have selected two sources of such materials: (i) platelet lysates, containing mostly globular proteins including relevant growth factors with highly regenerative potential; and (ii) proteins from amniotic membrane, composed of fibrical proteins such as collagens and other compoents of the extra-cellular matrix. Due to their hydrophilic nature and richness in chemically active groups, these proteins can be chemical modified to generate materials with new or improved properties, while maintaining the biochemical features of human tissues.

In a completely different viewpoint, we have been also leveraging the important role of the cells in the development of contructs for TE. Exploring human cells as materials precursors is an exciting conception to design living materials with adequate functional and structural properties similarly to what ensues in the human body. In our group we have been proposing possibilities of using lower relative amount of biomaterials in the hybrid constructs in order to assemble human cells in different geometries, including partially-coated cells, spherical aggregates (spheroids), fibres (fiberoids) and membranes (cell-sheets). Examples will be given on how bioengineered constructs could be obtained at different dimensional and length scales, mainly focusing on bone tissue regeneration.