A versatile DVD-based time-stretch imaging cytometry platform

Abstract

High-throughput time-stretch imaging is proven predominantly in format of microfluidic suspension, and thus in the applications of imaging flow cytometry. Nevertheless, this ultrafast technology has yet been compatible with imaging cells on solid-substrate platforms – a widespread strategy adopted in standard microscope-based imaging cytometry or cell assays. The throughput of these common image-based methods is primarily limited by the compromise between static field-of-view (FOV) and imaging speed (fps) in standard imaging sensors. Alternative methods such as automated microscope systems incorporating mechanical scanning devices can image with a large FOV without sacrificing image resolution. However, the throughput is still inherently bottlenecked by mechanical inertia. We here report a new type of time-stretch imaging cytometry platform compatible with both cells (adherent or specifically captured) and tissue sections fixed on a solid spinning substrate at known radial position and rotational speed. We implement this assay by modifying a commercial digital versatile disc (DVD) drive such that the rotational speed can be arbitrarily and stably controlled. Human breast cancer cells (MCF-7) and cartilage tissue sections are fixed on polycarbonate substrates, which are the commercial DVD, and imaged under high spinning speed (2400 rpm). The system, integrated with time-stretch imaging, can provide cellular resolution (~2 μm in radial direction) at high line-scan rate (11 MHz) and wide arbitrary spinning rate (900-4000 rpm). The integration of time-stretch imaging with this versatile DVD platform opens a wider scope of applications covering real-time monitoring of cultured living adherent cells, single-cell imaging immunoassay, ultralarge-scale tissue section imaging for digital histopathology.