Top-down nanofabrication of silicon nanoribbon field effect transistor (Si-NR FET) for carcinoembryonic antigen detection

Abstract

Sensitive and quantitative detection of tumor markers is highly required in the clinic for cancer diagnosis and consequent treatment. A field-effect transistor-based (FET-based) nanobiosensor emerges with characteristics of being label-free, real-time, having high sensitivity, and providing direct electrical readout for detection of biomarkers. In this paper, a top–down approach is proposed and implemented to fulfill a novel silicon nano-ribbon FET, which acts as biomarker sensor for future clinical application. Compared with the bottom–up approach, a top–down fabrication approach can confine width and length of the silicon FET precisely to control its electrical properties. The silicon nanoribbon (Si-NR) transistor is fabricated on a Silicon-on-Insulator (SOI) substrate by a top–down approach with complementary metal oxide semiconductor (CMOS)-compatible technology. After the preparation, the surface of Si-NR is functionalized with 3-aminopropyltriethoxysilane (APTES). Glutaraldehyde is utilized to bind the amino terminals of APTES and antibody on the surface. Finally, a microfluidic channel is integrated on the top of the device, acting as a flowing channel for the carcinoembryonic antigen (CEA) solution. The Si-NR FET is 120 nm in width and 25 nm in height, with ambipolar electrical characteristics. A logarithmic relationship between the changing ratio of the current and the CEA concentration is measured in the range of 0.1–100 ng/mL. The sensitivity of detection is measured as 10 pg/mL. The top–down fabricated biochip shows feasibility in direct detecting of CEA with the benefits of real-time, low cost, and high sensitivity as a promising biosensor for tumor early diagnosis.

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“…The p-type double gate nanodevices, which have been improved from the early single gate devices, were fabricated with a “top-down” approach, shown in Figure 3. The original material used for silicon nanowire devices was a 6-inch SOI wafer, which consisted of a 195 nm thick silicon layer, a 120 nm SiO 2 insulating layer, and a 600 μm thick silicon substrate 18. First, the 195 nm thick silicon layer was oxidized for 7 hrs to form a layer of SiO 2 via dry-oxygen oxidation combined with a wet-oxygen oxidation mode.…”

“…This method is based on signal conversion, and the detection in biological and electrical signals was mark-free, immediately responsive, highly sensitive, and specific 17. Studies have demonstrated successful tumor marker detection in low-salt solutions (including CEA, AFP, and PSA) 14,18,19. However, detection sensitivity in a high-salt concentration (such as whole blood and serum) was reduced or nonexistent due to interference from a high-salt concentration 20–22.…”

Biosensing based on field-effect transistors (FET): Recent progress and challenges

“…The surface of the device was modified with APTES, GA, and anti-CEA, and a microfluidic channel was added on top of it. This approach was successful enough to detect down to 10 pg/mL of the analyte [ 89 ]. Or Gao and colleagues designed a microfluidic sensing platform based on CMOS-compatible SiNW-FET for the identification of lung cancer biomarkers ((miRNA)−126 and CEA).…”

“… Application Target RE Linker Surface Sensor Readout LOD Sample Ref. Disease antigen detection CEACAM5 CEACAM1 Antibody GTA SiO 2 /SiNW Potentiometric Off-chip 18 ng/mL and 21.6 ng/mL Buffer solution [ 92 ] Prostate cancer diagnosis PSA PSA antibodies APTES GA AuNPs SiO 2 /SiNW Potentiometric Off-chip 90 pg/mL Serum [ 93 ] Oncological diseases diagnosis oDNA Complementary oDNA probe molecule APTES DTSSP cross-linker a stack of h-k PEALD dielectrics, HfO 2 and Al 2 O 3 Amperometric Off-chip 10 -16 M Buffer solution (potassium phosphate buffer) [ 94 ] CEA detection CEA Antibody APTES GA SiNx/SiNRs CMOS-compatible FET Off-chip 10 pg/mL Buffer solution (PBS) [ 95 ] Lung cancer diagnosis miRNA−126 and CEA probe DNA and anti-CEA antibody APTES GA SiNW CMOS-compatible FET Off-chip 0.1 fM and 1 fg/ml Buffer solution (PBS) [ 96 ] PSA detection PSA DNA aptamers PYCOOH EDC/NHS PEG ETA SiO 2 /graphene FET channel/Si 3 N 4 FET Off-chip 1 nM Buf...…”

Optical Properties of GaAs Nanowires with an Electric Potential That Varies Inversely with the Square of the Radial Distance

“…In medicine, they have been utilized in a broad spectrum of branches like osteology, for example, using a combination of nanowires and nanoparticles to repair bones with defects [4]. Silicon nanoribons have also been used as biosensors to detect carcinoembryonic antigen [5]. The potential of titanate nanowires to remove Uranium (VI) from the environment has been investigated [6].…”