Some very early testing of fluorescence imaging in our optical
tweezers instrument. A 10 kb long piece of DNA (ca 3 um long
when stretched) is held between two optically trapped
microspheres. The DNA is coated with a fluorescent dye (SYBR-
gold) which is exited by a 488 nm blue laser and the
fluorescence signal is collected with a CCD camera looking
through a narrow-band filter centered on the emission spectrum
of SYBR-gold. At around 1:10 in the video there's a double-
tether (two DNA-molecules between the beads). We don't want that
but there is not much that we can do about it, except discard
the data. At the very end there's an image of QDots on the
coverglass surface. A ~48 000 base-pair long (ca 16 um) piece of
DNA is stretched between two optically trapped ca 2 um diameter
polystyrene beads. Bright-field real-time view through a 100x
microscope. Scale-bar in microns on the right. Some promising
results yesterday with trying to stretch DNA molecules. The
molecule is attached between two microspheres, and w