雷射光鉗是一項利用光壓特性的研究技術。在此文章中我們用Labview程式，模擬幾何光學的理論計算與環境條件，繪出幾何光學模型的曲線分布圖，用來與實驗比較。再利用852nm、50mW的雷射光對1μm及3μm聚苯乙稀微粒垂直捕捉與U937細胞水平捕捉的實驗，聚苯乙稀微粒的垂直捕捉力會因為聚苯乙稀微粒在樣本空間的位置不同而有所不同。當微粒在靠近樣本空間邊界時所需的捕捉力要比微粒在樣本的中央時所需的捕捉力來的大3-5倍。我們也將雷射光鉗應用在細胞上，當使用U937細胞，細胞的大小約為20μm。雷射光鉗能捕捉住細胞，並將其移動並固定到一定的地方。同時雷射光鉗也能應用在生命科學的研究上，例如利用雷射光鉗研究聚苯乙稀微粒與U937細胞之間的吸附力，或是不同細胞之間的作用力。

Using radiation pressure to manipulate micro-size particle, optical tweezers is a novel tool on studying cell molecular biology. In this thesis, a LabView program was constructed with ray optical model to calculate the radiation pressure difference inside a polystyrene sphere for comparison with the experimental data. A diode laser, 852nm and 50mW, was used to trap the polystyrene beads with 1 and 3 mm in diameter and the U937 living cells. Comparing the vertical trapping force on the polystyrene beads at different distance to the cover slit, we can study the boundary effects on the trapping conditions. The vertical trapping forces required near the glass boundary are 3 to 5 times larger than that they were in the center of the solvent. We also demonstrate the capabilities of trapping an U937 (about 20 mm in diameter) living cell with this tweezers. The trapping force on the cells is much smaller than the polystyrene beads due to their irregularity and the small index of refraction. Manipulation of living cells makes the measurement of single cell interaction and communication possible. Further studies may help us understand the mystery of life.

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