• 沒有找到結果。

本論文研究兩個系統毛細管系統與微流道系統在不同照射時間、

不同脈衝數和不同光通量情況下的殺菌效果。並根據結果設計出較高 效率的流道。實驗結果可以歸納為以下三點結論:

第一,由圖 4.1~4.11 可知隨著照射時間增加,單位光通量所能消 滅細菌數的實驗結果、平均一隻細菌所接收能量的實驗結果以及平均 一隻細菌所接收脈衝數的實驗結果在兩個系統中皆呈現線性的負相 關(由於是雙對數圖故可知為非線性關係),以 LD90 時的數據來看,

毛細管系統中一開始效率較低,推測是因為處理的菌液量是微流道系 統的十倍,總細菌數較多,但兩個系統的利用率都比前人的實驗來的 高,達成提高效率的目標。

第二,由圖 4.13 可知在固定光通量實驗中,若雷射能量低於臨 界能量(Power:25mW),殺菌效率會顯著下降,而 Power 等於 25mW 時尖峰能量密度為 0.66GW/cm2與 2007 年 Shaw-Wei D. Tsen 與 K.T.

Tsen 用可見光飛短脈衝雷射對大腸桿菌做殺菌實驗[20]結果相符。

第三,在討論脈衝數與殺菌效果的關係時,可肯定即便單位脈衝 能量再大,細菌也絕非一個脈衝所能殺死的,推測是因為一個細菌有 許多 DNA,一個脈衝能量再大也只能打斷一條 DNA,故須累積一定

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數量的脈衝才能破壞多數 DNA,造成細菌死亡。

根據這三點結論我們設計出效率增加超過 30 倍的流道。

以下以血液製品-新鮮冷凍血漿做範例討論

新鮮冷凍血漿內含有效成份: 血漿 120ml;所有凝血因子 100ml;

無血小板。一單位為 135ml。解凍後不能退回血庫,應於六小時之內 輸用。

現有的血液製品消毒技術 MirasolTMa InterceptTMa [29] 可達到細 菌衰減量對數下降約為 2.5 也就是生存率為 0.3%,我們以此為標準,

對照圖 4.15 可知在舊流道時流速 0.02 ml/Hour 時生存率為 1%,流速 0.25 ml/Hour 時生存率為 30%,用 0.02 ml/Hour 流完再用 0.25 ml/Hour 流過,即可達到細菌衰減量對數下降 2.5 的菌液。改用截面積較大的 新流道時先用流速 3.2 ml/Hour 流一遍,再用 40ml/Hour 的流速消毒 一次,即可達到生存率下降為 0.3%的殺菌效果,消毒一單位所需的 時間為 45.5 小時。

若病人情況緊急,只能進行 4.5 小時手術,則需準備 3W 聚焦光 點半徑 100μm 的脈衝雷射,如此一來流道設計也擴大為寬度 200μm 深度 2.8mm,由於截面積又增加了 10 倍,故流速可再提高,先用 32ml/Hour 流一遍,再用 400ml/Hour 的流速消毒一次,即可達到生存 率下降為 0.3%的殺菌效果,消毒一單位所需的時間為 4.5 小時。

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未來可以使用 Mode-Locked Femtosecond Titanium : Sapphire Laser ( 型號為 Model Trestles –LH6)所輸出的波長 830nm,能量 800mW 的雷射進行實驗,因為能量較大,可以加大流道尺寸設計,

預期可以有更高的效率,只是可見光殺菌機制主要由色素吸收雷射光,

產生單態氧進而破壞脂肪分子造成細菌死亡,其中色素對 830nm 的 光吸收率不高,故選擇提高能量而降低吸收率造成的效率是否比較高 仍須研究。

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