2015

Fabrication of High-Performance Ultrathin In2O3 Film Field-Effect Transistors and Biosensors Using Chemical Lift-Off Lithography

J. Kim; Y. S. Rim; H. Chen; H. Cao; N. Nakatsuka et al. 

We demonstrate straightforward fabrication of highly sensitive biosensor arrays based on field-effect transistors, using an efficient high-throughput, large-area patterning process. Chemical lift-off lithography is used to construct field-effect transistor arrays with high spatial precision suitable for the fabrication of both micrometer- and nanometer-scale devices. Sol–gel processing is used to deposit ultrathin (∼4 nm) In2O3 films as semiconducting channel layers. The aqueous sol–gel process produces uniform In2O3 coatings with thicknesses of a few nanometers over large areas through simple spin-coating, and only low-temperature thermal annealing of the coatings is required. The ultrathin In2O3 enables construction of highly sensitive and selective biosensors through immobilization of specific aptamers to the channel surface; the ability to detect subnanomolar concentrations of dopamine is demonstrated.

ACS Nano

2015-03-23

Vol. 9 , num. 4, p. 4572-4582.

DOI : 10.1021/acsnano.5b01211

Controlled DNA Patterning by Chemical Lift-Off Lithography: Matrix Matters

H. Cao; N. Nakatsuka; A. Serino; W-S. Liao; S. Cheunkar et al. 

Nucleotide arrays require controlled surface densities and minimal nucleotide–substrate interactions to enable highly specific and efficient recognition by corresponding targets. We investigated chemical lift-off lithography with hydroxyl- and oligo(ethylene glycol)-terminated alkanethiol self-assembled monolayers as a means to produce substrates optimized for tethered DNA insertion into post-lift-off regions. Residual alkanethiols in the patterned regions after lift-off lithography enabled the formation of patterned DNA monolayers that favored hybridization with target DNA. Nucleotide densities were tunable by altering surface chemistries and alkanethiol ratios prior to lift-off. Lithography-induced conformational changes in oligo(ethylene glycol)-terminated monolayers hindered nucleotide insertion but could be used to advantage via mixed monolayers or double-lift-off lithography. Compared to thiolated DNA self-assembly alone or with alkanethiol backfilling, preparation of functional nucleotide arrays by chemical lift-off lithography enables superior hybridization efficiency and tunability.

ACS Nano

2015-10-01

Vol. 9 , num. 11, p. 11439-11454.

DOI : 10.1021/acsnano.5b05546

Neurochips Enable Nanoscale Devices for High-Resolution In Vivo Neurotransmitter Sensing

N. Nakatsuka; A. M. Andrews 

Neuropsychopharmacology

2015-12-10

Vol. 41 , p. 378-379.

DOI : 10.1038/npp.2015.307