Pulse laser assisted optical tweezers for biomedical applications

Abstract

Optical tweezers which enables to trap micron to nanometer sized objects by radiation pressure force is utilized for manipulation of particles under a microscope and for measurement of forces between biomolecules. Weak force of optical tweezers causes some limitations such as particle adhesion or steric barrier like lipid membrane in a cell prevent further movement of objects. For biomedical applications we need to overcome these difficulties. We have developed a technique to exert strong instantaneous force by use of a pulse laser beam and to assist conventional optical tweezers. A pulse laser beam has huge instantaneous laser power of more than 1000 times as strong as a conventional continuous-wave laser beam so that the instantaneous force is strong enough to break chemical bonding and molecular force between objects and obstacles. We derive suitable pulse duration for pulse assist of optical tweezers and demonstrate particle manipulation in difficult situations through an experiment of particle removal from sticky surface of glass substrate.

Interaction of erythrocytes in the process of pair aggregation in blood samples from patients with arterial hypertension and healthy donors: measurements with laser tweezers

“…For example, there are setups that allow automated trapping and manipulation of single cells [9]. Alongside with continuous-wave lasers, pulsed lasers are also applied in LT schemes in order to improve the trapping efficiency and manipulating velocity [10]. Using a circularly polarised trapping beam, one can rotate the trapped cell [3].…”

Launch and capture of a single particle in a pulse-laser-assisted dual-beam fiber-optic trap

“…Pulsed-laser has been widely used in the field of laser cleaning, which produces a strong lifting force that could overcome adhesion forces and gravity to remove the particles quickly and efficiently [23][24][25] without considering the laser-induced damage to the particles. Moreover, pulse-laser-assisted optical tweezers (PLAT) open the possibility of manipulating stuck microparticles in aqueous environments and may find broad applications in cell biology and molecular biology [26][27][28]. Rapid loading and manipulation of a microsphere in air or vacuum remains challenge until now.…”