修飾之氮化銦離子感測場效電晶體對DNA雜合反應偵測

Functionalized InN Ion Sensitive Field Effect Transistor for DNA Hybridization Detection

林政毅(Cheng-Yi Lin)

指導教授 ： 葉哲良

國立清華大學/電機資訊學院/電子工程研究所/碩士(2009年)

https://doi.org/10.6843/NTHU.2009.00695

摘要

超薄膜 (~10 nm) 氮化銦 (InN) 離子感測場效應電晶體 (ISFET)，經分子氣相沉積(Molecular vapor deposition, MVD)技術，將 3-硫醇基矽丙烷 (3-Mercaptopropyltrimethoxysilane, MPTMS)以氣相法修飾在其閘極表面，以進行DNA雜和反應的偵測。超薄膜氮化銦離子感測場效應電晶體對於溶液中的陰離子，具有相當高的靈敏度與快速的反應時間，在化學與生物分子感測上展現出極大的應用可能。本研究以氣相沉積技術來矽烷化 (Silanization) 3-硫醇基矽丙烷，比起傳統的液相自組裝膜 (Self-assembled monolayer, SAM)，此技術能大大地縮短表面修飾的時間。藉水的接觸角驗證，首先在氧離子的電漿清潔後，氮化銦表面呈現0o角，而經1.5個小時的氣相 3-硫醇基矽丙烷修飾後，氮化銦表面可達68o。3-硫醇基矽丙烷的分子尾端具有硫醇 (-SH) 官能基，能用來固化在5端經丙烯酰胺 (Acrylic phosphoramidite) 修飾的DNA探針 (Probe DNA)。將表面覆有3-硫醇基矽丙烷的氮化銦離子感測場效應電晶體浸置到10 uM 的DNA探針溶液中持續12個小時後，修飾完成的氮化銦離子感測場效應電晶體便能與互補的單股DNA (5'-ATTGTTATTAGG-3') 進行雜合反應。我們觀察到當互補對DNA溶液滴入閘極表面時，氮化銦離子感測場效應電晶體的源汲極電流有明顯約6 uA的電流下降。此電流下降的原因可歸因為溶液中帶負電的互補DNA雜合黏附到閘極表面所引起。對於12個鹼基的寡聚核苷酸探針 (Oligonucleotide probe)，本研究已成功地偵測到 1 nM 的互補段目標 (Target) DNA，然而對帶有一個鹼基不匹配的非互補DNA，則偵測不到任何明顯的電流變化。

關鍵字

氮化銦離子感測場效應電晶體 ； DNA 雜合反應 ； 分子氣相沉積 ； 3-硫醇基矽丙烷 ； 生物分子感測器

並列摘要

Ultrathin (~10 nm) InN ion sensitive field effect transistors (ISFETs) with gate region modified with 3-mercaptopropyltrimethoxysilane (MPTMS) by molecular vapor deposition (MVD) are used to detect hybridization of deoxyribonucleic acid (DNA). The ultrathin InN ISFETs have a high sensitivity and short response time for anion detection, showing a great potential for chemical and biological sensing applications. Vapor-phase silanization of MPTMS using MVD substantially shortens the response time for surface modification compared to the conventional self-assembled monolayer (SAM) techniques. The change of contact angle of water on InN surface was observed from 0o, indicating the O2 plasma cleaning, to 68o after 1.5 h vapor deposition. MPTMS with -SH terminal functional groups was used to immobilize probe DNA with acrylic phosphoramidite modification at 5'-end. After immersed in 10 uM DNA probes solution for 12 h, the functionalized InN ISFET was used to perform the hybridization with complementary single stranded (ss) DNA 5'-ATTGTTATTAGG-3'. A drain-source current decrease (~6 uA) was observed when a complementary DNA was introduced to the gate region of ISFETs. The current decrease is attributed to the attachment of negatively charged DNA. For a 12-mer oligonucleotide probe, the detection of 1 nM target DNA was accomplished, while the noncomplementary DNA with one base mismatch did not show any obvious current variation.

並列關鍵字

InN ISFET ； DNA Hybridization ； Molecular Vapor Deposition (MVD) ； 3-mercaptopropyltrimethoxysilane (MPTMS) ； Biosensors

參考文獻

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