title: DNA adsorption measured with ultra-thin film organic field effect transistors.
abstract: 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.
authors.affiliation: CNR-Istituto per lo Studio dei Materiali Nanostrutturati, Via P. Gobetti 101, I-40129 Bologna, Italy.
authors.forename: P
authors.initials: P
authors.lastname: Stoliar
authors.forename: E
authors.initials: E
authors.lastname: Bystrenova
authors.forename: S D
authors.initials: SD
authors.lastname: Quiroga
authors.forename: P
authors.initials: P
authors.lastname: Annibale
authors.forename: M
authors.initials: M
authors.lastname: Facchini
authors.forename: M
authors.initials: M
authors.lastname: Spijkman
authors.forename: S
authors.initials: S
authors.lastname: Setayesh
authors.forename: D
authors.initials: D
authors.lastname: de Leeuw
authors.forename: F
authors.initials: F
authors.lastname: Biscarini
mesh_terms: 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
chemical_list: D009279:Naphthacenes; D004247:DNA; C523499:pentacene