Two different sensor geometries were compared to show which one minimizes the non specific signal

What is it about?

Porous materials offer a large surface to which molecules can bind. Thus, ideally, they can increase the sensitivity of detection schemes even by order of magnitudes. Yet a large surface constrained into a small volume implies that unwanted molecules might be trapped within the sensor during the analysis and give rise to a false positive signal. This signal is called unspecific signal and it is due to species that were not the target of the measurement but which still induec a sensor reponse. This article describes and quantifies how strong the effect is in nanoporous material optical sensors and demonstrate that the non specific signal might completely hidden the specific one, unless the surface is properly rinsed using a flow-through approach.

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Why is it important?

Ultra high sensitivity is often obtained only in laboratory using model samples (aka samples that contained dilutied solution of only the target molecule). In real applications several species are rpesent and interact with the sensor. One of the main factor that increase the minimum detectable concentration is the non specific signal. Thus it is of paramount importance to understand this interactions (which are specific for each type of sensors) in order to minimize them and reduce the limit of detection.

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