Development of an optical tweezer combined with micromanipulation for DNA and protein nanobioscience

We have constructed an optical tweezer using two lasers (830 nm and 1064 nm) combined with micropipette manipulation having sub-pN force sensitivity. Sample position is controlled within nanometer accuracy using XYZ piezo-electric stage. The position of the bead in the trap is monitored using single particle laser backscattering technique. The instrument is automated to operate in constant force, constant velocity or constant position measurement. We present data on single DNA force-extension, dynamics of DNA integration on membranes and optically trapped bead–cell interactions. A quantitative analysis of single DNA and protein mechanics, assembly and dynamics opens up new possibilities in nano-bioscience.