Dual-beam optical traps, used in conjunction with microfluidic channels, are used for manipulating µm-scale dielectric objects such as biological cells or polystyrene beads. This type of manipulation is helpful for studying the mechanical properties of soft particles and the dynamics of particles suspended in microfluidic flows, and for holding and observing living cells over extended periods of time. However, optical traps/microfluidic systems suitable for practical applications have been quite complicated and expensive to make, primarily due to the difficulties of holding optical fibers in place mechanically on the chip or of using in situ optical wave guides or lasers as substitutes for optical fibers. Of particular concern is the need to incorporate complex microfabricated components into a system’s design to make it compact enough for use with microscopes.
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