Small Machines, Big Inside Cells: 3D-Printed Devices Take Shape Within Living Cells

Researchers have 3D-printed microstructures inside living cells using two-photon polymerization by injecting a light-sensitive resin and curing it with a femtosecond laser; the resulting structures, including a 10 μm Elephant-like model, float in the cytoplasm and can be inherited when cells divide. Viability after 24 hours is about 55% for printed cells, with most losses due to membrane damage from the injection rather than the printing itself. Demonstrations include barcodes, diffraction gratings, and microlasers, signaling potential for intracellular tagging and sensing, while challenges in viability and integration remain.