DNA-Hybridization Detection on Si(100) Surfaces Using Light-Activated Electrochemistry: A Comparative Study between Bovine Serum Albumin and Hexaethylene Glycol as Antifouling Layers

Abstract

Light can be used to spatially resolve electrochemical measurements on a semiconductor electrode. This phenomenon has been explored to detect DNA hybridization with light-addressable potentiometric sensors and, more recently, with light-addressable amperometric sensors based on organic-monolayer-protected Si(100). Here, a contribution to the field is presented by comparing sensing performances when bovine serum albumin (BSA) and hexaethylene glycol (OEG) are employed as antifouling layers that resist nonspecific adsorption to the DNA-modified interface on Si(100) devices. What is observed is that both sensors based on BSA or OEG initially allow electrochemical distinction among complementary, noncomplementary, and mismatched DNA targets. However, only surfaces based on OEG can sustain electroactivity over time. Our results suggest that this relates to accelerated SiO formation occasioned by BSA proteins adsorbing on monolayer-protected Si(100) surfaces. Therefore, DNA biosensors were analytically explored on low-doped Si(100) electrodes modified on the molecular level with OEG as an antifouling layer. First, light-activated electrochemical responses were recorded over a range of complementary DNA target concentrations. A linear semilog relation was obtained from 1.0 × 10 to 1.0 × 10 mol L with a correlation coefficient of 0.942. Then, measurements with three independent surfaces indicated a relative standard deviation of 4.5%. Finally, selectivity tests were successfully performed in complex samples consisting of a cocktail mixture of four different DNA sequences. Together, these results indicate that reliable and stable light-activated amperometric DNA sensors can be achieved on Si(100) by employing OEG as an antifouling layer.

Functionalization of Oxide‐Free Silicon Surfaces for Biosensing Applications

“…CMOS based amperometric [89] SiNWFET PNA/DNA N/A 10 fm Zhang et al [126] SiNW DNA/DNA 2.5 × 10 13 molecules cm −2 10 pm Bunimovich. [127] Impedimetric DNA/DNA N/A 500 pm Wei et al [128] Amperometric COOH/LPS N/A 1.8 ng mL −1 Reta et al [129] LAE DNA/DNA N/A 500 pm Zarei et al [130] LAPS N/A N/A N/A Zhou et al [131] Figure 8. a) Illustration of a Si Nanowires on SiO 2 chip and b) Schematic Illustration of PNA functionalization that selectively bind to Si over enclosed SiO 2 .…”

“…This new approach was successfully implemented by Choudhury et al. [ 130,139,141 ] and allowed amperometric validation of DNA hybridization.…”

“…The small bandgap of silicon (1.1 eV) is such that visible light can be used, which becomes important for biological applications. This new approach was successfully implemented by Choudhury et al [130,139,141] and allowed amperometric validation of DNA hybridization.…”

Heterojunctions Based on Amorphous Silicon: A Versatile Surface Engineering Strategy To Tune Peak Position of Redox Monolayers on Photoelectrodes

“…Energetic aspects of charge-transfer across semiconductoraqueous electrolyte interfaces are of great importance to applications in energy conversion, 1-2 chemical sensors, [3][4][5] bioactive surfaces 6 and photocatalysis. [7][8][9][10][11] Among semiconductors, industrially relevant silicon has proven a valuable material with the development of self-assembled monolayers based on α,ω-dialkynes, 12 which are capable of avoiding anodic corrosion of silicon in aqueous electrolytes.…”

“…Energetic aspects of charge transfer across semiconductor–aqueous electrolyte interfaces are of great importance to applications in energy conversion, , chemical sensors, − bioactive surfaces, and photocatalysis. − Among semiconductors, industrially relevant silicon has proven a valuable material with the development of self-assembled monolayers based on α,ω-dialkynes, which are capable of avoiding anodic corrosion of silicon in aqueous electrolytes. , Further derivatization of the alkyne-terminated monolayer via click-chemistry allows the design of applications according to the redox potential of the clicked electroactive molecules. , …”