Detection of DNA hybridization using functionalized InN ISFETs
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1202-I09-09
Detection of DNA hybridization using functionalized InN ISFETs Cheng-Yi Lin1, Yen-Sheng Lu1, Shih-Kang Peng2, Shangjr Gwo3 and J. Andrew Yeh4 Institute of Electronics Engineering, National Tsing-Hua University, Hsinchu 30013, Taiwan 2 Department of Power Mechanical Engineering, National Tsing-Hua University, Hsinchu 30013, Taiwan 3 Department of Physics, National Tsing-Hua University, Hsinchu 30013, Taiwan 4 Institute of Nanoengineering and Microsystems, National Tsing-Hua University, Hsinchu 30013, Taiwan 1
ABSTRACT Ultrathin (~10 nm) InN ion sensitive field effect transistors (ISFETs) are functionalized by immobilized label-free oligonucleotide probes with 3-mercaptopropyltrimethoxysilane (MPTMS) through molecular vapor deposition (MVD) technique. This layer on the InN surface serves the function of selectively detecting the hybridization of complementary deoxyribonucleic acid (DNA). Using MVD technique to perform the gas-phase silanization of MPTMS provided a time-saving and simple method to reach 68° water contact angle after 1.5 h treatment. High resolution X-ray photoelectron spectroscopy (HRXPS) was employed to analyze the surface characteristics after functionalization. Modified probes DNA were covalently bonded to MPTMS-covered gate surface of InN ISFETs. And further hybridized with complementary DNA For a 12-mer oligonucleotide probe, a significant drain-source current decrease (~ 6 µA) was observed for the hybridization with complementary DNA solution of 100 nM. In contrast, the noncomplementary DNA with single-base mismatch did not show obvious current changes. Functionalized ultrathin InN ISFETs for DNA sequence detection demonstrate the promise of biological sensing and genetic diagnosis applications. INTRODUCTION Deoxyribonucleic acid (DNA) sequence can naturally hybridize with its complementary sequence due to the specific base-pairing rule. This useful property renders DNA probes can be used to detect genetic disease. There have been a variety of methods adopted to detect the DNA hybridization [1-4]. However, these approaches, normally, require prelabeling steps, timeconsuming optical measurements, or expensive instrumentation. To pursue label-free, rapid and accurate electrical detection, sensors based on semiconductor materials employing field effect transistor structure have been widely studied [5-7]. In particular, ultrathin InN ion sensitive field effect transistors (ISFETs) have attracted a lot of attention to be biosensors due to high sensitivity, biocompatibility and robust surface stabilities [8]. This purpose, however, requires a proper functionalization for obtaining the desired molecular recognition ability. To date, gas phase preparations have shown can provide better surface modification quality [9]. Molecular vapor deposition (MVD) is one kind of novel and effective coating technology to modify the surface due to a superior capacity of precisely controlling the process conditions [10]. In this work, we functionalize ultrathin InN ISFETs using label-free single strand DNA
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