Scanning Cytometry with a LEAP: Laser-Enabled Analysis and Processing of Live Cells In Situ

Background: Scanning cytometry now has many of the features (and power) of multiparameter flow cytometry while keeping its own advantages as an imaging technology. Modern instruments combine capabilities of scanning cytometry with the ability to manipulate cells. A new technology, called LEAP (laser-enabled analysis and processing), offers a unique combination of capabilities in cell purification and selective macromolecule delivery (optoinjection). Methods: LEAP-mediated cell purification and optoinjection effects were assessed in model experiments using adherent and suspension cell types and cell mixtures plated and processed at different densities. Optoinjection effects were visualized by delivering fluorescent dextrans into cells. Results were analyzed using the LEAP instrument’s own imaging system aswell as by fluorescence and confocal microscopy. Results: Live cell samples (adherent and suspension) could be purified to 90–100% purity with 50–90% yield, causing minimal cell damage depending on the cell type and plating density. Nearly one hundred percent of the targeted cells of all cell types examined could be successfully optoinjected with dextrans of 3–70 kDa, causing no visual damage to the cells. Indirect optoinjection effects were observed on untargeted cells within 5–60 lm to targeted areas under conditions used here. Conclusions: LEAP provides solutions in cell purification and targeted macromolecule delivery for traditional and challenging applications where other methods fall short. q 2006 International Society for Analytical Cytolog