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3.4 Applications of Optical Tweezers 113
Table 3.8. Applications of optical tweezers
technology fields applications
basic research 1. Physics: Measurement of optical pressure (1964)[3.1]
2. Biology: Measurement of swimming velocity of
bacteria (1987)[3.23]
3. Biology: Measurement of compliance of bacterial
flagella (1989)[3.24]
4. Chemistry: Microchemical conversion system (1994)[3.6]
5. Optics: Microsphere laser oscillation (1993)[3.29]
6. Biology: Kinesin stepping with 8 nm (1993)[3.25]
7. Mechanics: Measurement of particle rotation rate (1995)[3.34]
8. Mechanics: Measurement of the drag force on a
bead (1995)[3.33]
9. Physics: Optically trapped gold particle near-field
probe (1997)[3.31]
10. Biology: Single molecule observation (1998)[3.26]
industry 1. Space engineering: Solar sail flight [http://planetary.org]
2. Applied optics: Particle transport (1986)[3.19, 3.35]
3. Biological engineering: Living cell fusion (1991)[3.20]
4. Mechanical engineering: 3-D microfabrication (1992)[3.9]
5. Mechanical engineering: Shuttlecock type optical
rotor (1994)[3.8, 1.62]
6. Applied optics: Optical fiber trapping (1995)[3.13],
(1999)[3.15]
7. Mechanical engineering: Optical rotor with slopes(2003)[1.63]
8. Applied optics: Optically induced angular alignment (1999)
[3.17]
9. Mechanical engineering: Gear type optical rotor (2001)[1.65]
10. Applied optics: Optical mixer (2002)[1.50], (2004)[1.66]
11. Applied chemistry: Patterning surfaces with nanoparticles
(2002)[3.40, 3.41]
12. Applied optics: Microstructure formation and control (2004)
[3.39]

manipulation of bacteria and the measurement of the swimmingspeed of
mitochondria are shown in Fig. 3.39. Furthermore, living cell fusion [3.20] by
violet light exposure in the contact area of two cells trapped independently is
shown in Fig. 3.40.
Another example is the compliance measurement of bacterial flagella. The
torque generated by the flagella motor of a bacterium tethered to a glass
surface by a flagella filament was measured by balancing that generated by
the optical pressure force. The balance was realized by calibratingoptical
power [3.24].
The direct observation of kinesin steppingwas performed by optical
trappinginterferometry with a special and temporal sensitivity for resolving
movement on the molecular scale, as shown in Fig. 3.41 [3.25]. Silica spheres
carryingsingle molecules of the motor protein kinesin were deposited on mi-
crotubules usingoptical tweezers and their motion was analyzed to determine
whether kinesin moves in 8 nm steps.