原子力顯微鏡系統操作的奈米壓痕試驗(AFM nanoindentation)為生物表面力學量測的主要方法之一，AFM nanoindentation除了能改善傳統壓痕試驗的尺度問題及應用侷限性之外，相較於生物體在化學分析上的過程，此方法大幅降低了樣品製備的時間與複雜性，並能搭配適合之接觸模型，獲得生物表面在機械性質與生理結構的關聯性，然而因尺度過小的探針在接觸樣品表面後的面積難以定義，故相關壓痕探針的開發成為許多研究團隊努力的方向。
有鑑於球形壓痕探針在製程上的困難及高成本，吾人使用了雙束型聚焦離子束顯微鏡 ( Dual-Beam Focused Ion Beam System, DB-FIB )，於探針尖端進行離子束誘導沉積 ( Ion Beam Induced Deposition, IBID )，以製作出圓柱形、橢圓形等針尖形狀的探針，並加入商業及本實驗室自製之膠體探針，透過原子力顯微鏡針對高分子樣品量測其力與壓深深度之曲線，以探討不同針形最合適之接觸模型，進而計算出彈性模數的結果。除此之外，吾人利用高分子樣品的分析結果，接續在變異鏈球菌、老鼠及人類皮膚癌細胞上進行實驗，觀察真實生物表面帶來的力學性質變化。
本實驗主要能分成三大部分，第一部份為使用不同探針對高分子均質材料進行 AFM nanoindentation，並先行以Hertz模型擬和聚二甲基矽氧烷 ( Polydimethylsiloxane, PDMS )的實驗結果，發現各探針整體彈性模數的數值明顯與壓深距離的變化呈現正相關，無法清楚決定真正的彈性模數，故從力曲線斜率變化判斷出Flat punch模型才能高度符合真實接觸情形，且以消除針尖尺度因子為目的，吾人修正出不同探針的計算模型，應用於 PMMA及PVA材料中，亦同樣能從實驗結果觀察出差異。第二部份，在生物體的量測中，可發現利用修正模型計算出變異鏈球菌的彈性模數會隨著壓深距離的加大而下降，推測是由於菌體表面的細胞壁組織緊密程度與針尖形狀的交互作用所導致，而在小鼠及人類黑色素瘤細胞上，則發現彈性模數在一定壓深距離後，彈性模數趨於穩定，推論是細胞外間質( Extracellular matrix , ECM )的含量將會影響到細胞受力的變形量，並說明了ECM在細胞表面的密度高低是有可能影響到兩種細胞在彈性模數上的差異。最後，為了從不同針形得出的結果中，決定出真正的彈性模數，吾人以針尖角度的差別對彈性模數作圖並嘗試建立出不同探針適用之應用流程，發現角度越低的針形在接觸當下，樣品所受應力只能集中於針尖最前端，若樣品有強烈的黏彈性造成Sink-in effect，更容易導致彈性模數值過度預估，故須衡量黏彈性的現象並搭配適合角度的探針所得之彈性模數才較合理。
本實驗成功以AFM nanoindentation 量測出生物表面的力學性質，並以適當的模型計算出合理的彈性模數，而在未來的研究方向，也希望能以微機電系統(MEMS) 方向進行導電奈米壓痕探針的大量製備，探討生物表面在電性質方面的現象，以期建立出更完整的生物資料庫，應用於臨床醫療的發展。

In view of the problematic process and high cost of the spherical nanoindentation probes , we used a Dual-Beam Focused Ion Beam System (DB-FIB) to make a cylindrical probe, oval probe, and other probe with different shapes, and measured the surface mechanical properties of the polymer homogeneous material and the real biological sample through AFM nanoindentation compared with the commercial and self-made colloidal probes . From the results, we inferred that the lower the tip angle was, the stress could only be concentrated on the end of the tip. At this time, if the sample had strong viscoelasticity which would cause the Sink-in effect easily, it was easy to result in the miscalculation of the elastic modulus. Therefore, in order to obtain a more reasonable elastic modulus, it was necessary to evaluate the degree of viscoelasticity effect and matched the suitable tip angle.

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