Optical tweezers
Our optical tweezers room
Our optical tweezers is located in a temperature controlled room with all noise generating controllers and computers located outside of the room. The setup is very user-friendly and sample steering, camera, as well as lasers can be controlled via an Xbox controller. With sub-pN force resolution and a stable optical trap we can assess the biomechanical properties of polymers.
How to measure biomechanical properties of biopolymers using optical tweezers
This video illustrates how to measure the biomechanical properties of a bacterial pili, that is, the surface organelles that bacteria such as E. coli use for attachment to host surfaces. In short, 10 µm polystyrene beads are immobilized to a coverslip and coated with poly-L-lysine to make them sticky. A bacterium can be trapped and mounted on this bead. A small 2 µm bead is thereafter trapped, the stiffness of the trap is calibrated, and subsequently the bead is brought in close proximity of the bacterium so the bead attaches to a pilus. By separating the bacterium and bead, the biomechanical properties of the pilus can be measured.
Our setup
Schematic view of our LTRS setup with integrated digital holographic imaging. We have integrated three lasers with different wavelengths and a white light source (WLS). To make DHM images, a green laser (λ0 = 532 nm, green line) is used, for Raman excitation we use the NIR laser (λ1 = 808 nm) and for trapping, we use an IR laser (λ2 = 1064 nm). With this setup, we can record Raman spectra from 300 cm-1 to 2400 cm-1. This region contains much information regarding nucleic acids, proteins, polysaccharides, carbo-hydrates and lipids in cells