CRP and TNF-α Detection using Porous Silicon Substrate Based on Reflectometric Interference Fourier Transform Spectroscopy

Sepsis is one of the leading causes of death in intensive care units (ICU) and is becoming more prevalent globally. As a result, an accurate and timely diagnosis of sepsis is critical for selecting the best treatment to prevent disease progression and mortality. In this study, CRP and TNF-α as common biomarkers of sepsis were detected using a label-free optical biosensor based on interferometric Fourier transform spectroscopy from a porous silicon substrate. The porous silicon layer was chemically modified with APTES and glutaraldehyde to immobilize the aptamer covalently in order to capture the analyte. The refractive index of the porous layer was determined by analyzing the reflection spectrum from the porous layer, which was associated with different biomarker concentrations. The results demonstrated linear responses in concentrations ranging from 10-10000 ng/ml for CRP and 100-10000 ng/ml for TNF-α and the biosensor's high discrimination. Thus, it has a high potential for advancement in clinical sepsis diagnosis.