A high-throughput all-optical laser-scanning imaging flow cytometer with biomolecular specificity and subcellular resolution

Image-based cellular assay advances approaches to dissecting complex cellular characteristics through direct visualization of cellular functional structures. However, available technologies face a common challenge, especially when it comes to the unmet need for unraveling population heterogeneity at single-cell precision: higher imaging resolution (and thus content) comes at the expense of lower throughput, or vice versa. To overcome this challenge, a new type of imaging flow cytometer based upon an all-optical ultrafast laser-scanning imaging technique, called free-space angular-chirp-enhanced delay (FACED) is reported. It enables an imaging throughput (> 20,000 cells sec-1) 1-2 orders-of-magnitude higher than the camera-based imaging flow cytometers. It also has two critical advantages over optical time-stretch imaging flow cytometry, which achieves a similar throughput: (1) it is widely compatible to the repertoire of biochemical contrast agents, favoring biomolecular-specific cellular assay; (2) it enables high-throughput visualization of functional morphology of individual cells with sub-cellular resolution. These capabilities enable multiparametric single-cell image analysis which reveals cellular heterogeneity, e.g. in the cell-death processes demonstrated in this work – the information generally masked in non-imaging flow cytometry. Therefore, this platform empowers not only efficient large-scale single-cell measurements, but also detailed mechanistic analysis of complex cellular processes.