This video playfully demonstrates the versatile manipulation of single biomolecules using JPK’s NanoTracker optical tweezers platform, simultaneous to sensitive fluorescence microscopy in a JPK’s microfluidics flow cell. A native (non-fluorescent) DNA molecule is suspended between two optically trapped beads. A continuous fluid flow is applied using a multichannel laminar flow cell. The buffers flowing by can be changed by moving the microscope sample stage between various laminar channels. In the video, the trap-held DNA molecule is suspended successively in a plain buffer and in a flow of fluorescently labeled DNA molecules, coated with fluorescent proteins that specifically bind to the DNA. Towards the end of the video, one such fluorescent DNA molecule connects to the invisible one, like a rope on the washing line.
Such assays can be used to combine quantitative mechanical manipulation using optical traps with protein binding kinetics studies using fluorescence. The combination of techniques makes such assays particularly powerful.
(Fluorescent Rad51 proteins courtesy of Dr. M. Modesti, CNRS Marseille)
Post time: Aug-03-2017