Optical Trapping of Cells

In one report, the optical gradient field (/l = 808 nm) was used to interact with cells and beads and to measure the resultant time-of-flight. This method (known as optophoresis) has successfully differentiated between cancerous versus non-cancerous cells (breast cancerous melanoma) [867]. 

Optical trap or tweezers were used to select single suspension cells (acute myeloid leukemia, AML) in a PET film-sealed PMMA chip. The use of the thin 

PET film (35 pm) was necessary in order to allow the use of a high-magnification microscopic objective needed for optical trapping. This cell selection usually took about 5 min. Subsequent cell lysis and CE separation of the cell contents were 

In one report, the optical tweezers were used to hold a bend in order to stretch a DNA molecule. First, a DNA molecule (XDNA) was biotin-congugated so that it could be attached to a streptavidin-coated polystyrene bead. The bead was held by optical tweezers inside a PDMS chip. The other end of the DNA was labeled with digoxigenin to be immobilized on the channel coated with anti-digoxigenin antibody. The DNA was stretched by moving the chip, with the bead being held by the optical tweezers [868]. 

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