Biological tissues have a remarkable ability to organize themselves and change shape, a process driven by the forces generated by their own cells. Harnessing this natural behaviour to design synthetic living materials capable of adopting predetermined shapes is currently one of the major challenges in bioengineering. However, precisely controlling how a tissue behaves and directing its internal forces so that it adopts exactly the desired shape remains a significant challenge for science.
Now, a study published in Science presents a new strategy for "programming" changes in shape: it proposes using chemical cues to control how cells orient themselves within the tissue. The result is living tissue capable of deforming in a controlled manner to generate reproducible three-dimensional structures.
For Xavier Trepat, co-lead author of the study, professor at the Faculty of Medicine and Health Sciences at the University of Barcelona and ICREA research professor at the Institute for Bioengineering of Catalonia (IBEC), this is particularly significant. "We are demonstrating that we can design the shape a living tissue will adopt just by controlling how its cells are oriented," says the researcher, who is also head of the IBEC's Integrative Cell and Tissue Dynamics group and a member of the CIBER Area for in Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN).
The scientists describe the study's results as a means of designing living surfaces that change shape on their own, with potential applications ranging from tissue engineering to biohybrid robotics. "The orientation of the cells controls the forces, and the forces can control the formation of a three-dimensional shape," explains Pau Guillamat, a researcher at the IBEC's Integrative Cell and Tissue Dynamics group and the study's first author.
Marino Arroyo, full professor at the Department of Civil and Environmental Engineering at the Universitat Politècnica de Catalunya, and co-leader of the study, says: "Our models have allowed us to examine different hypotheses and, ultimately, identify the mechanism by which cell orientation drives the three-dimensional folding of tissues. Furthermore, they provide a quantitative relationship between nematic pattern and shape."
The study was carried out in collaboration with IBEC's Cellular and Molecular Mechanobiology group, led by Pere Roca-Cusachs, professor at the UB's Faculty of Medicine and Health Sciences.
