Accurate position tracking of optically trapped live cells

Position clamping of optically trapped microscopic non-spherical probes.

We investigate the degree of control that can be exercised over an optically trapped microscopic non-spherical force probe. By position clamping translational and rotational modes in different ways, we are able to dramatically improve the position resolution of our probe with no reduction in sensitivity. We also demonstrate control over rotational-translational coupling, and exhibit a mechanism...

Autofluorescence spectroscopy of optically trapped cells.

Cellular autofluorescence spectra were monitored in a single-beam gradient force optical trap ("optical tweezers") in order to probe the physiological effects of near infrared and UVA (320-400 nm) microirradiation. Prior to trapping, Chinese hamster ovary cells exhibited weak UVA-excited autofluorescence with maxima at 455 nm characteristic of beta-nicotinamide adenine dinucleotide (phosphate) ...

Holographic tracking and sizing of optically trapped microprobes in diamond anvil cells.

We demonstrate that Digital Holographic Microscopy can be used for accurate 3D tracking and sizing of a colloidal probe trapped in a diamond anvil cell (DAC). Polystyrene beads were optically trapped in water up to Gigapascal pressures while simultaneously recording in-line holograms at 1 KHz frame rate. Using Lorenz-Mie scattering theory to fit interference patterns, we detected a 10% shrinkin...

Accurate Position Tracking Using Inertial Measurement Units

Near-infrared Raman spectroscopy of single optically trapped biological cells.

We report on the development and testing of a compact laser tweezers Raman spectroscopy (LTRS) system. The system combines optical trapping and near-infrared Raman spectroscopy for manipulation and identification of single biological cells in solution. A low-power diode laser at 785 nm was used for both trapping and excitation for Raman spectroscopy of the suspended microscopic particles. The d...