Techniques

Magnetic Tweezers of all flavors

Magnetic tweezers are a single-molecule technique with wide applicability in the study of processive motor proteins and other enzymes, yielding insight into their kinetics and mechanochemistry. In addition to the conventional magnetic tweezers that can apply force and torque to biological molecules, our laboratory has expanded the different types of magnetic tweezers available so that they can also be used to measure torque or twist.

Optical Tweezers of all flavors

dna3Optical tweezers involved focus laser beams that can trap beads and are highly useful in single-molecule biophysics experiments. We employ them in two contexts: first, integrated with with our nanopores (see also below), so that we can use the optical tweezer to precisely position a bead-tethered nucleic acid with respect to the pore, and also to measure the forces encountered by the nucleic acids when captured inside the pore; second, for the control and measument of torque in nucleic acids using optical tweezers that manipulate birefringent particles.

Microfluidics

microfluidic_device
The use of microfluidics in biological research has gained much popularity in recent years. We fabricate a versatile device with growth channels, capable of being used to study different bacterial species in a high-thoughput manner. In its design, cells are confined in the growth channels oriented perpendicularly to a trench through which growth medium is flown. This allows us to study a large number of cells that inherit the same cell pole over multiple generations. Cells are immobilized, in the absence of chemical fixation, at the far end of such a growth channel (ca. 25 µm in length). The length of the growth channels is chosen so as to ensure sufficient supply of nutrients to the bacteria by diffusion, which allows us to simultaneously study numerous different cells for extensive periods of time.

Genetic engineering

For live-cell imaging, we perform genetic engineering in order to introduce genetically-encoded fluorophores into the bacterial chromosome.