title: Highly Disordered Array of Silicon Nanowires: an Effective and Scalable Approach for Performing and Flexible Electrochemical Biosensors.
abstract: The direct integration of disordered arranged and randomly oriented silicon nanowires (SiNWs) into ultraflexible and transferable electronic circuits for electrochemical biosensing applications is proposed. The working electrode (WE) of a three-electrode impedance device, fabricated on a polyimide (PI) film, is modified with SiNWs covered by a thin Au layer and functionalized to bind the sensing element. The biosensing behavior is investigated through the ligand-receptor binding of biotin-avidin system. Impedance measurements show a very efficient detection of the avidin over a broad range of concentrations from hundreds of micromolar down to the picomolar values. The impedance response is modeled through a simple equivalent circuit, which takes into account the unique WE morphology and its modification with successive layers of biomolecules. This approach of exploiting highly disordered SiNW ensemble in biosensing proves to be very promising for the following three main reasons: first, the system morphology allows high sensing performance; second, these nanostructures can be built via scalable and transferable fabrication methodology allowing an easy integration on non-conventional substrates; third, reliable modeling of the sensing response can be developed by considering the morphological and surface characteristics over an ensemble of disordered NWs rather than over individual NWs.
authors.affiliation: Institute for Microelectronics and Microsystems, National Research Council, via del Fosso del Cavaliere 100, 00133, Rome, Italy.
authors.forename: Luca
authors.initials: L
authors.lastname: Maiolo
authors.affiliation: Institute for Microelectronics and Microsystems, National Research Council, via del Fosso del Cavaliere 100, 00133, Rome, Italy.
authors.forename: Davide
authors.initials: D
authors.lastname: Polese
authors.affiliation: Institute for Microelectronics and Microsystems, National Research Council, via del Fosso del Cavaliere 100, 00133, Rome, Italy.
authors.forename: Alessandro
authors.initials: A
authors.lastname: Pecora
authors.affiliation: Institute for Microelectronics and Microsystems, National Research Council, via del Fosso del Cavaliere 100, 00133, Rome, Italy.
authors.forename: Guglielmo
authors.initials: G
authors.lastname: Fortunato
authors.affiliation: Department of Physical Electronics, School of EE, Tel-Aviv University, Ramat-Aviv, 69978, Israel.
authors.forename: Yosi
authors.initials: Y
authors.lastname: Shacham-Diamand
authors.affiliation: Institute for Microelectronics and Microsystems, National Research Council, via del Fosso del Cavaliere 100, 00133, Rome, Italy.
authors.forename: Annalisa
authors.initials: A
authors.lastname: Convertino
mesh_terms: D015374:Biosensing Techniques / Q000295:instrumentation*; D017097:Electric Impedance; D004563:Electrochemistry / Q000295:instrumentation*; D004566:Electrodes; D006046:Gold / Q000737:chemistry; D053770:Nanowires / Q000737:chemistry* / Q000648:ultrastructure; D012825:Silicon / Q000737:chemistry*
chemical_list: D006046:Gold; D012825:Silicon
keywords: disordered silicon nanowires; flexible electronics; impedance biosensors; modeling