Two dimensional interferometric optical trapping of multiple particles and Escherichia coli bacterial cells using a lensed multicore fiber

Abstract

Two dimensional interferometric trapping of multiple microspheres and Escherichia coli has been demonstrated using a multicore fiber lensed with an electric arc fusion splicer. Light was coupled evenly into all four cores using a diffractive optical element. The visibility of the fringes and also the appearance of the lattice can be altered by rotating a half wave-plate. As a result the particles can be manipulated from one dimensional trapping to two dimensional trapping or a variety of different two dimensional arrangements. The ability to align bacterial populations has potential application for quorum sensing, floc and biofilm and, metabolic co-operation studies.

Scaling-up ultrasound standing wave enhanced sedimentation filters

“…These few devices are very successful for handling fluid volumes scales from cm 3 to m 3 but when very small scale, very large scale, high flow rates or continuous flow are needed these standard devices have limited development potential. At the sub-millilitre scale there are several particle manipulation processes based on physical characteristics which promise to increase the scope of microfluidic applications, for example electrostatic [1] and magnetic attraction [2], thermophoresis [3], microthermal field-flow fractionation (micro-TFFF), shear-induced particle migration [4], sedimentation based field-flow-fractionation [5], dean-flow inertial-focusing [6], electrowetting [7,8], optical traps [9], dielectrophoresis [10] and ultrasound-standing-wave particle filtration [11][12][13]. This last process, the subject of this paper, can in principle also be scaled up and it can also operate with: gas or liquid suspension phases; high or low media conductivity; and opaque or transparent samples.…”

Experimental and theoretical evaluation of the trapping performance of polymeric lensed optical fibers: single biological cells versus synthetic structures

“…11 Despite of the advantages of OFTs, the range of targets manipulated by these newly developed tools is still limited, as well as their mechanical and biological effects on more complex cellular structures remain poorly understood. 10,12,13 Only synthetic particles or simple biologic cells (e.g., yeasts, bacteria, Red Blood Cells) were so far successfully trapped using OFTs. 4,9,14,15 To the best of our knowledge, the most complex cellular entity that was manipulated by such kind of optical tools were neuroblastoma cells derived from a rodent cellular culture.…”

Optical trapping and orientation of Escherichia coli cells using two tapered fiber probes

“…Moreover, the difficulty in penetrating thick samples by the focus generated by the objective make it difficult to apply the system to thick samples. Fortunately, optical fibers provide an alternative approach to manipulate E. coli cells [13][14][15]. Among them, the fiber probe is a miniaturized and highly flexible tool for particle manipulation because light beams can be simply focused by the tip of the probe without the use of complicated optical components such as high-numerical-aperture objective.…”