Nanowrinkled Interface-Coupled Metaphase Chromosome Spreading and Nanoscale Conformability

Chromosome spreading is a key step in karyotyping and fluorescence-based analyses, yet it often suffers from limited dispersion, chromatid overlap, and morphological distortion due to operator-dependent variability. Here, we introduce an anisotropic, nanowrinkled polydimethylsiloxane (PDMS) substrate that enhances chromosome spreading by tuning droplet impact dynamics via anisotropic wetting and splashing-assisted transport. The uniaxial wrinkle geometry promotes lateral redistribution of the fixative droplet, leading to broader chromosome dispersion, stronger directional spreading, and improved chromatid separation compared with flat substrates. High-resolution atomic force microscopy reveals subtle but reproducible nanoscale surface modulations on chromosomes deposited on wrinkled PDMS, consistent with partial transcription of the underlying wrinkle relief during adsorption. The characteristic spacing of these modulations (∼300-500 nm) matches the wrinkle periodicity and is interpreted here as substrate-coupled nanoscale conformability, rather than as direct evidence of intrinsic chromatin organization. Collectively, these findings establish nanowrinkled PDMS as a practical, tunable platform for controlled chromosome deposition and further indicate that engineered nanoscale interfaces can elicit nanoscale conformability of metaphase chromosomes during adsorption.