Fabrication of Silicon Nanowire Sensors for Highly Sensitive pH and DNA Hybridization Detection

Abstract

A highly sensitive silicon nanowire (SiNW)-based sensor device was developed using electron beam lithography integrated with complementary metal oxide semiconductor (CMOS) technology. The top-down fabrication approach enables the rapid fabrication of device miniaturization with uniform and strictly controlled geometric and surface properties. This study demonstrates that SiNW devices are well-aligned with different widths and numbers for pH sensing. The device consists of a single nanowire with 60 nm width, exhibiting an ideal pH responsivity (18.26 × 106 Ω/pH), with a good linear relation between the electrical response and a pH level range of 4–10. The optimized SiNW device is employed to detect specific single-stranded deoxyribonucleic acid (ssDNA) molecules. To use the sensing area, the sensor surface was chemically modified using (3-aminopropyl) triethoxysilane and glutaraldehyde, yielding covalently linked nanowire ssDNA adducts. Detection of hybridized DNA works by detecting the changes in the electrical current of the ssDNA-functionalized SiNW sensor, interacting with the targeted ssDNA in a label-free way. The developed biosensor shows selectivity for the complementary target ssDNA with linear detection ranging from 1.0 × 10−12 M to 1.0 × 10−7 M and an attained detection limit of 4.131 × 10−13 M. This indicates that the use of SiNW devices is a promising approach for the applications of ion detection and biomolecules sensing and could serve as a novel biosensor for future biomedical diagnosis.

Point‐of‐Care Testing (POCT) Devices for DNA Detection: A Comprehensive Review

“…Moreover, the application of cross-linker such as glutaraldehyde, where the carboxyl terminated on their structure has been used for immobilizing the NH 2 -terminated DNA probes. [96][97][98] In Srisomwat's work, [99] the iTO substrate was deposited with the chitosan to allow covalent the NH 2 -terminated acpcPNA probe on the chitosan layer via glutaraldehyde linker. Another work of using Schiff-base reaction on electrochemical sensors was introduced by Avelino.…”

Recent Advances in Silicon Quantum Dot-Based Fluorescent Biosensors

“…[ 31 ]. Currently, several types of photoluminescent biosensors have been developed for detecting environmental and physiological markers such as Cu 2+ /F − [ 32 ], Cd 2+ [ 33 ], Fe 3+ [ 34 , 35 ] and DNA [ 36 ]. In this review, we summarize the recent advances in the direct preparation of SiQDs with good water solubility and their applications in biosensors.…”

Investigation on the non-linear behaviour of silicon nanowires and assessment of the biosensing potential

“…Some of these potential and continuously evolving applications include nanowire electronics [4,5], nanowire photovoltaics [6,7], nanowire thermoelectric [8,9] and interdisciplinary applications with promising value/ propositions like interfacing nanowires with living cells [10,11], bio detection (i.e. biosensors) etc [12][13][14][15][16][17][18]. Biosensors have enabled an excellent promise for the routine application of predictive, preventive, and personalized healthcare, with biochemical tests at a much larger scale, at much lower cost, and preferably at point-of-care locations.…”

“…But because of the multiple antibody association steps and the cost aspect of equipment for optical read-out, protein analysis by ELISA is not practical outside a clinical laboratory. SiNW devices, characterized by an exceptionally large surface to volume ratio, present new opportunities for marker detection because their physical and/or electrical properties are strongly modulated by surface functionalization [12][13][14][15][16][17][18]. SiNW surface is readily functionalized by wellestablished silane chemistry, enabling routine coupling of DNA and antibodies thereby eliminating the need for fluorophore attachment and costly optics for detection [12][13][14][15][16][17][18].…”

“…SiNW devices, characterized by an exceptionally large surface to volume ratio, present new opportunities for marker detection because their physical and/or electrical properties are strongly modulated by surface functionalization [12][13][14][15][16][17][18]. SiNW surface is readily functionalized by wellestablished silane chemistry, enabling routine coupling of DNA and antibodies thereby eliminating the need for fluorophore attachment and costly optics for detection [12][13][14][15][16][17][18]. Usually, a functionalized SiNW biosensor platform may comprise liquid-gating (figure 1) where a fixed drain voltage (V DS ) is applied across the NW and the Au or AgCl electrode is used to provide the liquid-gate voltage (V GS ) in the buffer of required ionic strength.…”