Enhancing porous silicon biosensors performance: the interplay of nanostructure design and microfluidic integration

Abstract

Abstract In this article, we investigate mass transfer acceleration approaches aimed at enhancing the performance of porous silicon (PSi)-based biosensors. PSi biosensors tend to suffer from relatively poor sensitivity due to mass transfer limitations, which can be attributed to several factors including the bulk diffusion of the target in the solution toward the biosensor surface, the hindered diffusion within the porous layer, and simultaneous reaction with the immobilized capture probe molecules. This study considers the impact of different PSi structural characteristics (such as the pore diameter, porous layer thickness, and the capture probe density) on the overall performance of such sensors. Additionally, we look at the effect of incorporating convection on the performance of PSi biosensors, via their integration into sophisticated 3D-printed microfluidic platforms. The proposed 3D-printed microfluidic designs include micromixer components that can be deployed for both passive and active mixing to achieve superior sensitivity. We show that tuning the PSi biosensor characteristics improve performance significantly – achieving a calculated limit of detection (LOD) of 50 nM, which is > 1 order of magnitude lower than the achieved in similar previously developed biosensors. Furthermore, the integration of PSi with the different microfluidic systems can indeed improve the sensitivity of the aptasensor, and the LOD can be reduced by > 1 order of magnitude.