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