Abstract: A sensor for detecting an analyte of interest in a fluid sample includes (i) a structure having a plurality of surficial walls that define a plurality of air gaps in the structure and (ii) a binding material. The structure is configured such that both a fluid sample lacking the analyte of interest and a fluid sample containing the analyte of interest are able to penetrate the plurality of air gaps. The binding material, which is present on the plurality of surficial walls, is able to bind the analyte of interest. The sensor is configured such that, when the analyte of interest binds to the binding material, a change in surface energy results within the plurality of surficial walls.

Abstract: A colorimetric sensor for detecting an analyte of interest in a fluid sample includes a photonic structure comprising a first receptor, wherein the photonic structure may be configured such that, when an analyte contacts the first receptor within the photonic structure, a refractive property of the photonic structure changes thereby to cause a detectable color change in the photonic structure. The first receptor may comprise an optical absorber indicator, wherein a second receptor is part of a structure of the optical absorber indicator, such that, when the analyte contacts the second receptor, the analyte causes a photo-induced electron transfer to induce a color change of the optical absorber indicator.