Sarcosine Prostate Cancer Biomarker Detection by Controlling Oxygen in NiO_x Membrane on Vertical Silicon Nanowires in Electrolyte–Insulator–Nanowire Structure

Abstract

Sarcosine prostate cancer biomarker with the low concentration of 1 pM has been detected by controlling oxygen from 1 to 15 sccm in a NiO x membrane on chemically etched vertical Si nanowires (SiNWs) in an electrolyte–insulator–nanowire (EIN) structure. The vertical Si nanowires with approximately 17 μm length and polycrystalline NiO x membrane are observed by both field-emission scanning electron microscope (FE-SEM) and high-resolution transmission electron microscope (HRTEM) images, respectively. The optimized NiO x membrane with oxygen content of 4 sccm on planar SiO x /Si substrate shows good pH sensitivity of approximately 50 mV/pH, low hysteresis of 3.4 mV, and low drift rate of 2.4 mV/h as compared to other oxygen content membranes of 1, 10, and 15 sccm. Further, uric acid with the concentration of 0.1 μM is detected directly by using the optimized NiO x membrane. In addition, repeatable H2O2 sensing with the low concentration of 10 pM as well as prostate cancer biomarker is detected, which is owing to the reduction–oxidation phenomena of the NiO x membranes. The sensing mechanism is owing to the Ni2+/Ni3+ oxidation states of the NiO x membrane, which is confirmed by X-ray photoelectron spectroscopy. The optimized NiO x membrane on vertical Si nanowire in the EIN structure shows a good drift rate of 3.84 mV/h and sarcosine detection with improvement of approximately 1000 times as compared to the planar Si in an electrolyte–insulator–semiconductor (EIS) structure. This sensor paves a way to detect early-stage diagnosis of prostate cancer rapidly in the near future.

Development of micropillar array electrodes for highly sensitive detection of biomarkers

“…47 The concentration of sarcosine higher than 2.67 mM maybe a clear indication of prostate cancer. 48 The LOD (1.28 mM) of mAE500 for sarcosine detection is much smaller than the cutoff value of mM. Therefore, the mAE500 in this paper demonstrates its potential in detecting sarcosine from either serum or urine for clinical applications with high sensitivity and reliability.…”

Aqueous-Based Silica Nanoparticles as Carriers for Catalytically Active Biomacromolecules

“…Figure shows the schematic of the one-pot synthesis of sarcosine oxidase encapsulated in silica nanoparticles. Sarcosine oxidase is an inducible bacterial flavoenzyme that catalyzes the oxidative demethylation of sarcosine and contains covalently bound flavin adenine dinucleotide, which has been extensively employed to develop biosensors for sarcosine detection. − …”

Recent advances in nanomaterials for prostate cancer detection and diagnosis

“…143 Roy et al grew vertical NiO x membrane-coated silicon nanowires on an n-type Si electrolyte to sense the concentration of uric acid, H 2 O 2 , and sarcosine based on the mechanism of Ni 2+ /Ni 3+ oxidation states of the NiO x membrane. 144 The vertical silicon nanowire-based substrate improved the catalytic activity of the NiO x membrane, therefore improving the LOD of sarcosine by 1000 times than that of the planar substrate. In addition, Cui et al fabricated a chip by in situ growth of silica nanowires on a commercial frosted slide and subsequent modification of anti-EpCAM, which could achieve a more effective capture of PCa cell line (PC-3).…”