近年來光學系統被廣泛的應用在不同層級上的研究，藉由光學的散射與吸收特性廣泛的應用於描述生物組織的光學特性，如將大腦切片或細胞放置於不同實驗環境下觀察其變化，其中光的散射特性被應用來量測細胞快速的細胞膜電位變化以及緩慢的細胞收縮和膨脹變化。因此在本研究中架設一套調頻的光學系統，選用近紅外光波段，觀察細胞體積在不同滲透壓下的變化，藉由比較原訊號與反向散射光訊號，可以得到調變訊號的振幅與相位角的改變。為了達到小區域量測細胞，藉由微操作器控制傳輸調變光源的探針，而其中包含了幾個重要的因素需要仔細考慮如：探針的設計、光波段的選擇、合適的量測深度等….。當系統架設完成後，本研究中藉由不同的滲透壓(±20, ±40 and ±60 mOsm)變化，觀察光散射特性變化與細胞形態變化的相關性。由實驗中我們可以明顯的觀察到當細胞受到不同滲透壓的刺激時光強度與相位角度的變化，反射回的散射光強度與滲透壓改變量呈現為線性負相關、相位角呈現為非線性的相關，且在高張環境中呈現上升穩定的現象。目前由結果顯示我們以反向式高靈敏度的方式，可以獲得光訊號隨著細胞改變的變化。

Among intrinsic optical properties, light scattering properties have been
commonly applied to describe the optical properties of target biological tissues, such
as brain slices and cells under different experimental conditions. In cellular level, light
scattering is employed to measure fast changes in membrane potential and slow
changes in cells swelling or shrinking. This study was to establish a
frequency-modulated optical system of near infrared range with the capability to
measure the amplitude and phase changes of the backward scattering light for
observing the changes of cell volume under different osmotic solutions. The
modulated light was guided via probe which was controlled by micromanipulator to
aim at minimum cluster of cells. Several factors including the probe design,
wavelength selection, optimal measuring distance between optical probe and cells
were considered. Our experimental setup was tested in cultured cells, whose
scattering property and surface morphology varied in different osmotic solutions (±20,
±40 and ±60 mOsm), to compare the relationship between changed scattered light and
varied cell morphology. We can observe evident changes in amplitude and phase in
the osmotic challenge conditions. The intensity of backscattering was inversely
proportional to osmotic changes. The phase change did not exhibit a linear
relationship but reached a plateau at hyperosmotic solution. Our study indicated that
the high sensitivity of backward scattering intensity makes it a potential alternative
approaches for observing cellular morphological changes.

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