Fig. 1

The nichoid culture substrate fabricated by two-photon laser polymerization (2PP). a The nichoid substrate, consisting of 168 squared blocks made up of 5 × 5 individual nichoids, laser written on a glass coverslip. To prevent cell adhesion on the flat substrate surrounding the surface covered by the nichoid blocks, a poly-dimethylsiloxane (PDMS) ring with a 7-mm inner diameter was UV-bonded to the glass coverslips (gray). b SEM of a nichoid block. c Detail of a single nichoid, which shares the lateral confinement walls with the neighboring nichoids of the 5 × 5 block