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Optical Manipulation of Particles and Cells Using Fiber Probes
Jinan University, China, People's Republic of
Great attention has been paid recently on optical trapping and manipulation of particles and cells. Different manipulation methods, such as optical methods, dielectrophoresis, and acoustic tweezers, have achieved fruitful results. Among them, optical methods have merits of high flexibility, targeting, and non-invasiveness. In this talk, I will talk optical manipulation of particles and cells using fiber probes. This non-invasive method provides potential applications for optofluidics, biophotonics, and single cell analysis.
1Université de Bourgogne-Franche Comté; 2Université Grenoble Alpes, CEA Grenoble
Due to the action of the scattering force, particles that are optically trapped at the surface of a waveguide are propelled in the direction of the light propagation. In this work, we demonstrate an original approach for creating tunable periodic arrays of optical traps along a few-mode silicon nanophotonic waveguide. We show how the near-field optical forces at the surface of the waveguide are periodically modulated when two guided modes with different propagation constants are simultaneously excited. The phenomenon is used to achieve stable trapping of a large number of dielectric particles or bacteria along a single waveguide. By controlling the light coupling conditions and the laser wavelength, we investigate several techniques for manipulating the trapped particles. Especially, we demonstrate that the period of the optical lattice can be finely tuned by adjusting the laser wavelength. This effect can be used to control the trap positions, and thus transport the trapped particles in both directions along the waveguide.
Design Of An Optofluidic Device For The Measurement Of The Elastic Modulus Of Deformable Particles
Massimiliano Maria Villone1, Janine K Nunes2, Howard A Stone2, Pier Luca Maffettone1
1University of Naples Federico II, Italy; 2Princeton University, USA
Suspensions carrying deformable inclusions are ubiquitous in nature and applications. Hence, high-throughput characterization of the mechanical properties of soft particles is of great interest.
Recently, a non-invasive optofluidic technique has been developed for the measurement of the interfacial tension between two immiscible liquids . We have adapted such technique to the case of soft solid beads, thus designing a non-invasive optofluidic device for the measurement of the mechanical properties of deformable particles from real-time optical imaging of their deformation.
The device consists of a cylindrical microfluidic channel with a cross-section reduction in which we make initially spherical soft beads flow suspended in a Newtonian carrier. By imaging the deformation of a particle in real time while it goes through the constriction, it is possible to get a measure of its elastic modulus through a theoretically derived-correlation. We provide both experimental and numerical validation of our device.
 S. D. Hudson et al., Appl. Phys. Lett., 2005, 87, 081905
Real-time Measurement of the Single Nanoparticle Electrophoretic Mobility
Bohdan Yeroshenko, Wouter Wassing, Allard P. Mosk, Sanli Faez
Utrecht University, Debye Institute for Nanomaterials Science, Utrecht, Netherlands
The electrophoretic mobility of a single nanoparticle depends on its surface charge and its environment. Thus the change of the mobility can reflect the change in its chemical and physical properties. We present a high-bandwidth method to measure the electrophoretic mobility, based on optical tweezers and electrophoresis. We envision studying of nanoscale chemical processes as a possible application of this method.