Cell patterning in vivo using microrobot specifically designed for tissue engineering applications

The arrangement of cells in a desired pattern at target positions, known as cell patterning, is a crucial technique for constructing desirable tissues. While cell patterning has been traditionally performed on substrates, <i>in vivo</i> approaches remain largely unexplored. <i>In vivo</i> cell-patterning techniques show potential for achieving accurate and reliable tissue regeneration by building new tissues at lesion sites in a highly controlled manner using various therapeutic cells. This study introduces a pioneering approach for cell patterning <i>in vivo</i> using a microrobot specifically designed for tissue engineering applications. The body of the microrobot was fabricated using serum albumin and magnetic nanoparticles, and cell membrane-anchoring regents were bound to its surface. This robot effectively captured cells and rapidly released them at target sites, minimizing the burden on the recipient. Using this robot, cellular patterns formed successfully on various biological components, including Matrigel, other cell types, and inflamed colon tissues, in 30 min. Furthermore, as a proof-of-concept, cell patterning was performed inside the colon of mice with colitis. To ensure clinical applicability, the cell-loaded microrobot was introduced near the target site <i>via</i> an endoscope and subsequently guided by a magnetic field to create stem cell patterns in damaged colon tissues. This microrobot-based cell patterning will contribute to the establishment of a new field, <i>in vivo</i> cell patterning, and the advancement of sophisticated stem cell-based therapies.