快速鑑定念珠菌種類之微流體晶片

Rapid Discrimination of the Candida Species Using an Electrokinetics-based Microfluidic Chip

張洛齊 ； 鄭宜肪 ； 張憲彰

《國家奈米元件實驗室奈米通訊》 19卷2期 (2012/06) Pp. 24-30

https://doi.org/10.29913/NDLC.201206.0005

摘要

本研究提出了一個由兩層玻片上下各設計有兩種不同的電極組之三維介電泳（DEP）微流體晶片，此晶片若輔以功能性微粒即可快速檢測微小分子。微管道中在連續流體注入下對表面修飾有寡核酸探針的次微米顆粒產生剪切應力，此時搭配適當的交流電電場之施加，會對該微粒誘發負DEP力進而沿斜型電極方向被導引，繼而匯諸於管道的末端V型電極組之前。藉該聚集的微粒之間會自然形成極高電場之便，再擇以恰當頻率（如900 kHz），會將經非對稱性PCR放大且具有螢光的受測單股DNA（ssDNA）片段，以正DEP力方式吸引入微粒間，進而驅使在流體沖刷之際也能有效的行雜合反應，且發現均能在少於2分鐘之內即可極明顯提高該ssDNA雜交選擇性，且靈敏度可達到10-12 pM（Picomolar），目前我們藉此晶片已成功完成念珠菌種類（Candida Species）的快速鑑別。

關鍵字

介電泳 ； DNA雜合 ； 流體剪應力 ； 多目標菌種檢測

並列摘要

We present a dielectrophoresis (DEP)-based 3D microfluidic chip that are capable of enhancing the sensitivity and selectivity of DNA hybridization by utilizing nucleotide immobilized beads, an AC electric field, and hydrodynamic shear in a continuous through-flow. After fluorescently labelling ssDNA molecules by asymmetric PCR, these molecules in a flowing solution were rapidly trapped using molecular DEP to a cusp-shaped nanocolloid assembly on a microfluidic chip with a locally amplified AC electric field gradient. The detection time can be reduced to sub-minute periods and the sensitivity can reach the pico-molar level due to the use of AC DEP that can effectively concentrate (at an optimal AC frequency of 900 kHz) molecules in a small region (~100 μm^2) instead of in the broad area as used in a conventional reactor (~10^6 μm^2). Continuous flow in a micro-channel provides a constant and high shear rate that can shear off most non-specific target-probe binding to enhance the discriminating selectivity. On-chip multi-target discrimination of the Candida species can be achieved within a few minutes under optimal conditions.

並列關鍵字

Dielectrophoresis ； DNA Hybridization ； Hydrodynamic Shear ； Multi-target Discrimination