Figure 1. Two-step patterning process and single-cell-tethering workflow.

(a) Microisland patterns were produced by UVO (185 nm) patterning into thin polyHEMA coatings (<0.5 μm). An aldehyde-functionalized organic silane was then vapour deposited to prepare for DNA printing. (b) Profilometry measurements show representative microisland features of 200 nm. (c) Spot arraying of NH₂-terminated oligonucleotides within each microisland was performed using the Nano eNabler system. After arraying of single-cell-sized spots, the entire slide underwent reductive amination using NaBH₄. (d) Representative image of four-component printed DNA patterns (scale bar, 100 μm). (e) Multiple cell populations are labelled with distinct DNA molecules presenting sequences complementary to the microisland DNA strands, washed and passed through a PDMS flow cell affixed to the patterned slides either sequentially at a density of ∼800,000 cells per cm² or in mixed solutions at a density of ∼400,000 cells per cm². Untethered cells are washed away, and the process is repeated for each cell type.