DNA adsorption measured with ultra-thin film organic field effect transistors.
Organic ultra-thin film field effect transistors (FET) are operated as label-free sensors of deoxyribonucleic acid (DNA) adsorption. Linearized plasmid DNA molecules (4361 base pairs) are deposited from a solution on two monolayers thick pentacene FET. The amount of adsorbed DNA is measured by AFM and correlated to the concentration of the solution. Electrical characteristics on the dried DNA/pentacene FETs were studied as a function of DNA concentration in the solution. Shift of the pinch-off voltage across a wide range of DNA concentration, from very diluted to highly concentrated, is observed. It can be ascribed to additional positive charges in the semiconductor induced by DNA at a rate of one charge for every 200 base pairs. The sensitivity 74 ng/cm(2), corresponding to 650 ng/ml, is limited by the distribution of FET parameters upon repeated cycles, and is subjected to substantial improvement upon standardization. Our work demonstrates the possibility to develop label-free transducers suitable to operate in regimes of high molecular entanglement.
Stoliar
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P
CNR-Istituto per lo Studio dei Materiali Nanostrutturati, Via P. Gobetti 101, I-40129 Bologna, Italy.
Bystrenova
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E
Quiroga
S D
SD
Annibale
P
P
Facchini
M
M
Spijkman
M
M
Setayesh
S
S
de Leeuw
D
D
Biscarini
F
F
D000327:Adsorption; D015374:Biosensing Techniques / Q000295:instrumentation* / Q000379:methods; D004247:DNA / Q000032:analysis* / Q000737:chemistry; D004563:Electrochemistry; D018625:Microscopy, Atomic Force; D049329:Nanostructures / Q000737:chemistry* / Q000648:ultrastructure; D009279:Naphthacenes / Q000737:chemistry*; D012680:Sensitivity and Specificity; D014173:Transistors, Electronic
D009279:Naphthacenes; D004247:DNA; C523499:pentacene