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病毒有多重?
Posted on Wednesday, March 24 @ 01:53:00 CST by TerryYeh

編輯:NanoForensics

Purdue大學生醫工程系Birck Nanotechnology Center Dr.Rashid Bashir的研究小組發表首次以微機電系統(microelectromechanical systems),來測量單一病毒重量的方法。根據該小組的結果,一個天花疫苗裡的牛痘病毒(vaccinia)約重9.5fg (femtogram, 10-15g),那約是一粒米的萬億分之一的重量。

這個毫微秤(microscale)測重的原理,是觀察物體重量增減時的共振頻率(resonant frequency)變化。首先,矽絕緣晶片(silicon-on-insulator wafer)經由四個步驟的蝕刻,而成型為與泳池邊的跳水跳板(springboard)類似的懸臂樑(cantilever beam)。而懸臂的共振變化,由雷射都卜勒振動儀(Laser Doppler Vibrometer)來作動態測量。本研究中彈簧–質量力學系統(spring-mass system) 的共振頻率變化和重量的增減,有極高的相關性(R2 = 0.9 )。當長5μm 、寬1.5μm、厚度30nm的懸臂樑上空無一物時,其共振頻率約為1.2MHz。懸臂樑上有vacinnia,共振頻率因為物體重量增加而減少約60kHz。此方法可測量微小到160 ag (attogram, 10-18g),共振頻率變化大約1KHz的物體。

參與此研究的Amit Gupta表示測量微小物體的重量,並非此微共振器(microresonator) 的唯一功能。如在懸臂樑塗上antibody,可成為高靈敏度的病毒檢測器,進一步以「微縮晶片實驗室」(labs-on-a-chip) 來預防及警示生物恐怖活動(Bioterrorism)和即時監測空氣中病毒含量。

目前有關病毒的生物檢測需從樣品中取得DNA來分析,如此耗時又屬破壞性分析方法。此研究成果提供了一個迅速且非破壞性的病毒初步檢測方式。

原始論文:
A. Gupta, D. Akin, and R. Bashir; Single virus particle mass detection using microresonators with nanoscale thickness.APPLIED PHYSICS LETTERS VOLUME 84, NUMBER 11, 15 MARCH 2004,1976-1978.

轉載自 Sciscape 網站


 

 

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