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.

Disordered array of Au covered Silicon nanowires for SERS biosensing combined with electrochemical detection

“…6a and discussed in more details in ref. 29 . This device is simply obtained by adding to the Au/SiNWs, the Au counter electrode (CE) and the Ag reference electrode (RE).…”

“…We have recently showed as a highly disordered array of SiNWs covered by a film of Au (Au/SiNWs) can act as performing electrochemical biosensor via electrochemical impedance spectroscopy (EIS) 29 . The key benefit is that disordered SiNWs can be easily obtained through high yield and large-area fabrication techniques as well as relative low temperature (350 °C) procedures compatible with polymeric films, i.e.…”

The rise of flexible electronics in neuroscience, from materials selection to in vitro and in vivo applications

“…Among these nanomaterials, the semiconductor NWs (generally covered with a conductive Au film) are very promising interfaces for interrogating the neurons both in intracellular and extracellular configuration. They allow (i) a significant reduction of the impedance over the a wide frequency range investigated frequency range [83,84] and (ii) the engulfing of neuron membrane [85,86], thus providing an increment in SNR. Lastly, Si-NW FETs have been successfully integrated in electronic systems within freestanding-engineered tissues and have been shown to have a great potential as neuron-nanoelectronics interfaces deliverable into biological materials by syringe injection [87].…”

Nanosilicon-Based Composites for (Bio)sensing Applications: Current Status, Advantages, and Perspectives

“…Therefore, different nano-Si/metal nanocomposites (MNps) have been widely employed for rationally designing and fabricating high-performance (bio)sensors for the detection of various chemical and biological species [144]. The deposition of metal nanoparticles/nanofilms over all types of nano-Si can be implemented by the following techniques: (i) magnetron sputtering [31,51,145,146,147,148,149]; (ii) immersion, chemical, and electrochemical depositions [13,20,27,150,151,152,153,154,155,156,157,158,159,160,161,162,163,164,165,166,167,168,169,170]; (iii) thermal evaporation [32,44,171,172,173,174,175,176,177,178,179]; and (vi) laser ablation technique/pulsed laser deposition [180,181].…”

“…Nowadays, nano-Si/MNps nanocomposites have been utilized for (bio)sensors based on SERS [12,20,31,32,51,145,149,150,151,152,153,154,155,165,168,173,175,176,177,178,182,183,184], optical [13,44,158,164,167,171,180], and electrical [27,146,148,156,159,160,161,162,166,169,170,172,173,179,181,185,186] responses. Among all of these approaches, SERS of MNps decorated nano-Si is extensively exploited as the most efficient spectroscopic phenomenon for high-sensitive sensing.…”