Application of laser optical tweezers in immunology and molecular genetics

Abstract

Optical tweezers, based on a compact diode pumped Nd:YAG laser providing 350 mW at 1,064 nm coupled into a Zeiss IM 35 microscope, were used to sort CD4+ T cells into a capillary for further mechanical handling and to establish contact between single human natural killer (NK) cells and human erythroleukemia cells (K562) as targets. After contact and a lag phase of a few tens of seconds, the target cell starts to change its morphology and membrane blebbing occurs. The kinetics of the attack of the NK cell on K562 cells is not straightforward but governed by temporal oscillations in the shape of the target cell (zeosis).In a second application, the optical tweezers are combined with a UV laser microbeam based on a pulsed UV laser and with flow cytometry and sorting. With the pulsed laser, segments of sorted chromosome 1 of the Chinese hamster karyotype (CHV 79) can be easily microdissected and subsequently collected using the optical tweezers. This allows preparation of a few hundred chromosome segments per day without mechanical contact and in an absolutely sterile way and thus may provide an interesting basic technique in any type of genome sequencing project.

Optical trapping and manipulation of neutral particles using lasers

“…Greulich and Berns were the first to use the tweezers technique in combination with the so-called ''microbeam'' technique of pulsed laser cutting (sometimes called ''laser scissors'' or ''scalpel'') for cutting and moving cells and organelles. Greulich's early work involved UV cutting and tweezers manipulation of pieces of chromosomes for gene isolation (95). Tweezers also was used to bring cells into contact with one another to effect cell fusion by cutting the common wall (96).…”

Light forces the pace: optical manipulation for biophotonics

“…158 This enabled the creation of hybrid cells that retained cell function. In other work, Seeger et al 159 used a laser microbeam to microdissect chromosomes collected by an optical trap and subsequently collected the chromosome segments using a glass capillary. 159 Similar methods can be used for the dissection of cellular organelles, cytoskeletal filaments, 160 or chromosomes.…”

“…In other work, Seeger et al 159 used a laser microbeam to microdissect chromosomes collected by an optical trap and subsequently collected the chromosome segments using a glass capillary. 159 Similar methods can be used for the dissection of cellular organelles, cytoskeletal filaments, 160 or chromosomes. [161][162][163][164] More recently, such systems can be used for the separation of individual cells from cell clusters.…”

Laser Microbeams and Optical Tweezers in Ageing Research

“…[15][16][17][18][19] The first combination of a laser microbeam and optical tweezers, and thus the first complete micromanipulation by light, has been used for the microdissection of chromosomes with subsequent collection of the chromosome fragments. [20,21] This combination is also used to drill a channel into the zona pellucida, the viscous envelope of mammalian egg cells, and to catch, with optical tweezers, a sperm cell for transport into this channel for in vitro fertilization, with very practical applications in cattle breeding [22] and human-reproduction medicine. [23] Figure 1 gives an overview of the historical development of the techniques and a glimpse on how a laser microbeam and optical tweezers are realized.…”