title: Manipulation and growth of birefringent protein crystals in optical tweezers.
abstract: We report on the trapping, rotation, and in-situ growth of birefringent tetragonal lysozyme crystals in optical tweezers operating at a wavelength of 1070 nm. Variation of the pH and lysozyme concentration of the solution during growth was used to alter the length to width ratio of the crystals, and hence their orientation in the tweezers. Crystals with the optical axis skewed or perpendicular to the trapping-beam axis could be rotated by changing the orientation of linearly polarized light. We observed spontaneous spinning of some asymmetric crystals in the presence of linearly polarized light, due to radiation pressure effects. Addition of protein to the solution in the tweezers permitted real-time observation of crystal growth.
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Singer
authors.forename: Halina
authors.initials: H
authors.lastname: Rubinsztein-Dunlop
authors.forename: Ursula
authors.initials: U
authors.lastname: Gibson