Research on Biological Detection Based on Reflected Light Images of a Porous Silicon Bragg Mirror

Shuangshuang Zhang,Miao Sun,Zhenhong Jia,Jianfeng Yang,Xiaoyi Lv,Xiaohui Huang

doi:10.1109/jphot.2021.3059684

Abstract

In this paper, based on the gray value change of reflected light image of porous silicon (PSi) Bragg mirror, a fast and simple biological detection method is proposed. In this method, CdSe/ZnS quantum dots (QDs) are used as markers for refractive index amplification, and digital image method is used for detection. The detection light has the same wavelength as the lowest reflectivity of the edge of the Bragg mirror, and the reflected light radiated on the surface of the Bragg mirror is received by the detector. The theoretical simulation results show that the intensity of the reflected light increases with the increase of the refractive index caused by the biological reaction. According to the experimental results, the average gray value variation increases with the increase of the target DNA concentration and becomes a linear relationship in a certain range. Based on this method, the DNA detection limit is 20.74 pM. The method is low-cost, has a short detection time and can be used in the detection of biosensor microarray.

Highlights

As a nanostructured material, porous silicon has many advantages, such as large specific surface area, good biological activity and biocompatibility [1]–[3]
CdSe/ZnS quantum dots (QDs) are used as markers for refractive index amplification, and digital image method is used for detection
Since the porous silicon (PSi) Bragg mirror is functionalized, its reflection spectrum will redshift and the incident angle of the incident light will be adjusted so that the detection light of 633 nm will incident on the surface of the Bragg mirror at an angle of 108°, so that the reflected light intensity is the minimum and the reflected light is the darkest

Summary

Introduction

Porous silicon has many advantages, such as large specific surface area, good biological activity and biocompatibility [1]–[3]. Electrochemical corrosion and photolithography can be used to fabricate optical devices to enhance and amplify optical signals [4], [5]. These methods are widely used in optical biosensors [6]–[8]. Bomin Cho et al prepared distributed Bragg mirrors (DBR) via electrochemical corrosion and studied the optical properties and surface derivatization of DBR PSi and modified protein A within the DBR PSi. The biological reaction caused changes of the refractive index and detected human immunoglobulin (IgG) via the changes of the reflection spectrum [15]

Methods

Results

Conclusion