DNA Hybridization Measured with Graphene Transistor Arrays.
Adv Healthc Mater
; 9(16): e2000260, 2020 08.
Article
em En
| MEDLINE
| ID: mdl-32602657
ABSTRACT
Arrays of field-effect transistors are fabricated from chemical vapor deposition grown graphene (GFETs) and label-free detection of DNA hybridization performed down to femtomolar concentrations. A process is developed for large-area graphene sheets, which includes a thin Al2 O3 layer, protecting the graphene from contamination during photolithographic patterning and a SiOx capping for biocompatibility. It enables fabrication of high-quality transistor arrays, exhibiting stable close-to-zero Dirac point voltages under ambient conditions. Passivation of the as-fabricated chip with a layer composed of two different oxides avoids direct electrochemical contact between the DNA solutions and the graphene layer during hybridization detection. DNA probe molecules are electrostatically immobilized via poly-l-lysine coating of the chip surface. Adsorption of this positively charged polymer induces a positive shift of the Dirac point and subsequent immobilization of negatively charged DNA probes induces a negative shift. Spatially resolved hybridization of DNA sequences is performed on the GFET arrays. End-point as well as real-time in situ measurements of hybridization are achieved. A detection limit of 10 fm is observed for hybridization of 20-nucleotide DNA targets. Typical voltage signals are around 100 mV and spurious drifts below 1 mV per hour.
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01-internacional
Base de dados:
MEDLINE
Assunto principal:
Técnicas Biossensoriais
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Idioma:
En
Ano de publicação:
2020
Tipo de documento:
Article