Liu Y, Cheng D K, Sonek G J, Berns M W, Chapman C F, Tromberg B J
Department of Electrical and Computer Engineering, University of California, Irvine 92717, USA.
Biophys J. 1995 May;68(5):2137-44. doi: 10.1016/S0006-3495(95)80396-6.
The confinement of liposomes and Chinese hamster ovary (CHO) cells by infrared (IR) optical tweezers is shown to result in sample heating and temperature increases by several degrees centigrade, as measured by a noninvasive, spatially resolved fluorescence detection technique. For micron-sized spherical liposome vesicles having bilayer membranes composed of the phospholipid 1,2-diacyl-pentadecanoyl-glycero-phosphocholine (15-OPC), a temperature rise of approximately 1.45 +/- 0.15 degrees C/100 mW is observed when the vesicles are held stationary with a 1.064 microns optical tweezers having a power density of approximately 10(7) W/cm2 and a focused spot size of approximately 0.8 micron. The increase in sample temperature is found to scale linearly with applied optical power in the 40 to 250 mW range. Under the same trapping conditions, CHO cells exhibit an average temperature rise of nearly 1.15 +/- 0.25 degrees C/100 mW. The extent of cell heating induced by infrared tweezers confinement can be described by a heat conduction model that accounts for the absorption of infrared (IR) laser radiation in the aqueous cell core and membrane regions, respectively. The observed results are relevant to the assessment of the noninvasive nature of infrared trapping beams in micromanipulation applications and cell physiological studies.
通过红外（IR）光镊对脂质体和中国仓鼠卵巢（CHO）细胞进行捕获，结果显示会导致样品发热，温度升高可达数摄氏度，这是通过一种非侵入性的、空间分辨荧光检测技术测量得出的。对于由磷脂1,2 - 二酰基 - 十五烷酰 - 甘油 - 磷酸胆碱（15 - OPC）构成双层膜的微米级球形脂质体囊泡，当使用功率密度约为10(7) W/cm2、聚焦光斑尺寸约为0.8微米的1.064微米光镊将囊泡固定时，观察到温度升高约为1.45±0.15℃/100 mW。发现样品温度的升高在40至250 mW范围内与施加的光功率呈线性关系。在相同的捕获条件下，CHO细胞的平均温度升高近1.15±0.25℃/100 mW。红外镊捕获导致的细胞加热程度可以用一个热传导模型来描述，该模型分别考虑了红外（IR）激光辐射在细胞水性核心区域和膜区域的吸收情况。观察结果与评估微操纵应用和细胞生理学研究中红外捕获光束的非侵入性有关。
