Department of Physics, Simon Fraser University, 8888 University Drive, Burnaby, British Columbia, Canada.
J Biophotonics. 2010 Apr;3(4):224-33. doi: 10.1002/jbio.200900107.
The well calibrated force-extension behaviour of single double-stranded DNA molecules was used as a standard to investigate the performance of phase-only holographic optical tweezers at high forces. Specifically, the characteristic overstretch transition at 65 pN was found to appear where expected, demonstrating (1) that holographic optical trap calibration using thermal fluctuation methods is valid to high forces; (2) that the holographic optical traps are harmonic out to >250 nm of 2.1 mum particle displacement; and (3) that temporal modulations in traps induced by the spatial light modulator (SLM) do not affect the ability of optical traps to hold and steer particles against high forces. These studies demonstrate a new high-force capability for holographic optical traps achievable by SLM technologies.
单链 DNA 分子的力-延伸特性经过精密校准，可以作为标准来研究纯相位型全息光镊在高力条件下的性能。具体来说，在 65pN 处观察到特征性的超拉伸转变，这表明（1）使用热波动方法校准全息光阱在高力条件下是有效的；（2）全息光阱在 2.1 微米颗粒位移超过 250nm 时仍然是谐和的；（3）空间光调制器（SLM）引起的阱中时间调制不会影响光学阱在高力条件下保持和引导颗粒的能力。这些研究表明，通过 SLM 技术，全息光阱实现了新的高力能力。
