Kinetics of photo-stimulated adsorption of enzyme molecules onto n- and p-type silicon

A V Kozlowski,S V Stetsyura

doi:10.1088/1757-899x/699/1/012022

Abstract

We report on a change in the surface density of glucose oxidase (GOx) molecules on surface of Si/SiO2/polyethyleneimine structures depending on type of Si conductivity, adsorption time and white-light illumination of a substrate during GOx adsorption. It is clearly shown by AFM images that the dependence of GOx adsorption on adsorption time and illumination is different for n-Si and p-Si substrates. The results can be explained by the electrostatic interaction between GOx molecules and the surface charge of Si, which depends on illumination.

Highlights

Atomic force microscopy (AFM) was used to study the kinetics of photo-stimulated adsorption (PSA) of GOx molecules onto the surface of both p- and n-type silicon
GOx molecules from Aspergillus niger was used as enzyme molecules
The PEI molecules were adsorbed on silicon substrates from the 1 mg/ml aqueous solution during 10 min followed by rinsing in water during 10 min and drying

Summary

Introduction

AFM was used to study the kinetics of photo-stimulated adsorption (PSA) of GOx molecules onto the surface of both p- and n-type silicon. The experiments were performed with single-crystal silicon wafers of n-type (ρ = 4 Ω cm) and p-type (ρ = 8 Ω·cm). The substrates were boiled in a peroxide–ammonia solution and rinsed in deionized water (resistivity 18.2 MΩ·cm). This treatment leads to “reconstruction” of a native oxide layer while the silicon surface acquires negative charge in deionized water due to activation of OH-groups.

Results

Conclusion