Uniform DNA Biosensors Based on Threshold Voltage of Carbon Nanotube Thin-Film Transistors

Uniformity is a key parameter to assure the accuracy of biosensor devices. In this work, highly uniform carbon nanotube thin-film transistors (CNT-TFTs) with a standard deviation of threshold voltage ([Formula: see text]) as small as 0.04 were achieved by accurately controlling the fabrication process, which is so far the most stable distribution to our knowledge. On-state current ([Formula: see text]), off-state current and on/off current ratio also exhibit high uniformity with low standard deviation of 0.50, 0.72 and 0.54, respectively. Given the high uniformity, high stability and high sensitivity, the CNT-TFTs are used as ultra-sensitive 5-hydroxymethyl cytosine (5-hmC) detecting devices for the first time, which is one of the important modified bases in DNA and plays an important role in epigenetics. After attachment of 5-hmC DNA, a reproducible and stable shift of 18.7–59% in [Formula: see text] as well as a 31–54% change in [Formula: see text] were observed in the transfer characteristics curves of CNT-TFTs. Thus, a detecting device of 5-hmC in DNA segments could be designed based on the highly uniform CNT-TFTs.