Current robots can manipulate only surface-attached cells seriously limiting the fields
of their application for single cell handling. We developed a computer vision-based
robot applying a motorized microscope and micropipette to recognize and gently isolate
intact individual cells for subsequent analysis, e.g., DNA/RNA sequencing in 1–2 nanoliters
from a thin (~100 μm) layer of cell suspension. It can retrieve rare cells, needs
minimal sample preparation and can be applied for virtually any tissue cell type.
Combination of 1 μm positioning precision, adaptive cell targeting and below 1 nl
liquid handling precision resulted in an unprecedented accuracy and efficiency in
robotic single cell isolation. Single cells were injected either into the wells of
a miniature plate with a sorting speed of 3 cells/min or into standard PCR tubes with
2 cells/min. We could isolate labeled cells also from dense cultures containing ~1,000
times more unlabeled cells by the successive application of the sorting process. We
compared the efficiency of our method to that of single cell entrapment in microwells
and subsequent sorting with the automated micropipette: the recovery rate of single
cells was greatly improved.
