超音波是一項非常成熟穩定及容易作用的技術，不論是在治療、影像、清洗、刺激…等，其中低強度超音波刺激技術已廣泛應用於各領域，強化欲達成的效果，過去研究顯示低強度超音波的機械振盪能促使細胞產生特性的變化。因此本實驗使用超音波刺激的聲波振盪，觀察低強度超音波對纖維母細胞在回補膽固醇的速度及回補量的影響，並利用光學顯微鏡觀察纖維母細胞受到去除膽固醇及回補時的細胞大小、形態。此外奈米壓痕技術具備簡諧震盪的壓痕探針及精密的荷重與位移感測器，此量測技術能獲得待測物連續接觸剛性與壓痕深度之變化，將用以觀察細胞機械性質的變化。
將細胞加入MβCD去除膽固醇，取30分鐘、1小時、4小時、6小時時間點的細胞，準備進行奈米壓痕的機械性質檢測；回補膽固醇，取同樣時間點的細胞；另一組回補膽固醇的同時，給予強度ISATA50mW/cm2，頻率1MHz，工作週期20%的超音波刺激10分鐘，準備進行奈米壓痕機械性質的檢測。
利用奈米壓痕儀器量測去膽固醇後細胞的機械性質與未去膽固醇前的區別比較：由細胞表面對簡諧接觸剛性與深度關係曲線斜率，代表著細胞膜對簡諧震盪探針在最初20奈米的接觸時的力學反應，進行奈米力學性質的分析，同時以光學顯微鏡觀察細胞形態的改變，兩者結果都與細胞反應相互對應。

The mechanical properties of cells have been verified to correlate to human diseases and aging as well as to various cellular physiological processes, including proliferation, migration, and differentiation. It thus is essential to investigate responses of cells corresponding to chemical and physical stimulations for cellular mechanics studies and other applications. Moreover, measurement of the stiffness of an interested cell is of great importance to comprehend the cellular response with respect to a specific biophysical or biochemical alteration. Hence, current study aims to investigate the effect of low-intensity pulsed ultrasound (LIPUS) on nano-mechanical properties of cholesterol-manipulated cells. The NIH-3T3 fibroblasts were firstly incubated in cholesterol depletion solution. The cells were then insonified by a 1 MHz LIPUS for ten minutes during the process of cholesterol restoration. In situ observation on the variations of living cells adhered on the glass substrate was monitored continuously. The cellular morphological changes were recorded for 8 hours. The nano-mechanical properties of cells were detected with nano-indentation by measuring the cellular membrane of a single cell. The cell properties seemed to be unchanged when adding with serum. On the other hand, the cholesterol depletion tended to lead a majority of cells to retract and become rounding corresponding to the increase of incubation time. The complications may be alleviated with the insonification of LIPUS. The elastic properties of those cholesterol-manipulated cells following LIPUS insonification tended to be improved. This study demonstrates that the variations of nano-mechanical property of cell membrane during cholesterol restoration and LIPUS insonification may be sensitively detected using the depth-sensing nano-indentation technique. The LIPUS insonification may be beneficial to the restoration of elastic properties of cholesterol-manipulated cells.

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