A DNA-based molecular machine is described which has two movable arms that are pushed apart when a strand of DNA, the fuel strand, hybridizes with a single-stranded region of the molecular machine. Through the process of branch migration, a second strand of DNA complementary to the fuel strand is able to remove the fuel strand from the molecular machine, restoring it to its original configurati...

We present a dual-trap optical tweezers setup which directly measures forces using linear momentum conservation. The setup uses a counter-propagating geometry, which allows momentum measurement on each beam separately. The experimental advantages of this setup include low drift due to all-optical manipulation, and a robust calibration (independent of the features of the trapped object or buffer...

Techniques that can dexterously manipulate single particles, cells, and organisms are invaluable for many applications in biology, chemistry, engineering, and physics. Here, we demonstrate standing surface acoustic wave based "acoustic tweezers" that can trap and manipulate single microparticles, cells, and entire organisms (i.e., Caenorhabditis elegans) in a single-layer microfluidic chip. Our...

Both optical tweezers and acoustic tweezers have been demonstrated for trapping small particles in diverse biomedical applications. Compared to the optical tweezers, acoustic tweezers have deeper penetration, lower intensity, and are more useful in light opaque media. These advantages enable the potential utility of acoustic tweezers in biological science. Since the first demonstration of acous...

Microscopically controlled neutral atoms in optical tweezers and lattices have led to exciting advances in the study of quantum information and quantum many-body systems. The light shifts of atomic levels from the trapping potential in these systems can result in detrimental effects such as fluctuating dipole force heating, inhomogeneous detunings, and inhibition of laser cooling, which limits ...

Optical tweezers use the momentum of photons to trap and manipulate microscopic objects, contact-free, in three dimensions. Although this technique has been widely used in biology and nanotechnology to study molecular motors, biopolymers and nanostructures, its application to study viruses has been very limited, largely due to their small size. Here, using optical tweezers that can simultaneous...

We describe the design and construction of two different types of multiple-beam optical tweezers, each equipped with nanometer-resolution position detectors. Multiple optical traps can be created either by splitting a laser beam in two parts, based on its polarization, or time-sharing a single beam among several different locations. The advantages and disadvantages of optical tweezers based on ...

The size of particles that can be trapped in optical tweezers ranges from tens of nanometers to tens of micrometers. This size regime also includes large single molecules. Here we present experiments demonstrating that optical tweezers can be used to collect polyethylene oxide molecules suspended in water. The molecules that accumulate in the focal volume do not aggregate and therefore represen...