Flow-Through Porous Silicon Membranes for Real-Time Label-Free Biosensing

TL;DR

This paper introduces flow-through porous silicon membranes for biosensing, significantly improving response times and enabling rapid, multiplexed label-free detection of biomolecules in integrated sensor arrays.

Contribution

It presents a novel flow-through PSi membrane design that enhances molecule transport and response speed compared to traditional flow-over methods.

Findings

Six-fold faster response time for high molecular weight analytes

Successful integration of multiple sensors in microarrays

Demonstrated potential for rapid, multiplexed biosensing

Abstract

A flow-through sensing platform based on open-ended porous silicon (PSi) microcavity membranes that are compatible with integration in on-chip sensor arrays is demonstrated. Due to the high aspect ratio of PSi nanopores, the performance of closed-ended PSi sensors is limited by infiltration challenges and slow sensor responses when detecting large molecules such as proteins and nucleic acids. In order to improve molecule transport efficiency and reduce sensor response time, open-ended PSi nanopore membranes were used in a flow-through sensing scheme, allowing analyte solutions to pass through the nanopores. The molecular binding kinetics in these PSi membranes were compared through experiments and simulation with those from closed-ended PSi films of comparable thickness in a conventional flow-over sensing scheme. The flow-through PSi membrane resulted in a six-fold improvement in sensor response time when detecting a high molecular weight analyte (streptavidin) versus in the flow-over PSi approach. This work demonstrates the possibility of integrating multiple flow-through PSi sensor membranes within parallel microarrays for rapid and multiplexed label-free biosensing.