Study on the Physical Properties of a SiNW Biosensor to the Sensitivity of DNA Detection.

Siti Noorhaniah Yusoh,Khatijah Aisha Yaacob

doi:10.3390/ma14195716

Abstract

SiNW (silicon nanowire) arrays consisting of 5- and 10-wires were fabricated by using an atomic force microscope—the local anodic oxidation (AFM-LAO) technique followed by wet chemical etching. Tetramethylammonium hydroxide (TMAH) and isopropyl alcohol (IPA) at various concentrations were used to etch SiNWs. The SiNWs produced were differed in dimension and surface roughness. The SiNWs were functionalized and used for the detection of deoxyribonucleic acid (DNA) dengue (DEN-1). SiNW-based biosensors show sensitive detection of dengue DNA due to certain factors. The physical properties of SiNWs, such as the number of wires, the dimensions of wires, and surface roughness, were found to influence the sensitivity of the biosensor device. The SiNW biosensor device with 10 wires, a larger surface-to-volume ratio, and a rough surface is the most sensitive device, with a 1.93 fM limit of detection (LOD).

Highlights

Silicon nanowires (SiNWs) are categorized as one-dimensional (1D) nanomaterials with diameters in the range of 2 to 100 nm, exhibiting two types of conductivity—p-type and n-type conductivity [1,2,3]
The fabricated SiNW devices were characterized under AFM contact mode topography and the results shown in Figure 1b–d were obtained with respect to the etching parameters
The results show that the surface roughness decreases as the isopropyl alcohol (IPA) concentration increases

Summary

Introduction

Silicon nanowires (SiNWs) are categorized as one-dimensional (1D) nanomaterials with diameters in the range of 2 to 100 nm, exhibiting two types of conductivity—p-type and n-type conductivity [1,2,3]. Silicon nanowires can be fabricated by using two approaches— bottom-up or top-down—with controllable compositions, morphologies, structures, and dimensions [1,4,5]. SiNWs are attracting attention because of their exclusive properties, which can be integrated into biosensor device structures [12]. A biosensor is a device that has the ability to detect a biomolecule-related element with a suitable transducer and translate it to a measurable signal [13]. The nanostructure is a crucial element for future biosensor devices due to its small size. Innovations in transducers have conceivably produced useful approaches to new detection techniques, transforming the way in ‘sensing’

Methods

Results

Conclusion