A food item freshness notification system may include a remote device and a gas sensor configured to sense gas adjacent the food item and generate food item freshness data related thereto. The food item freshness notification system may also include a food item freshness server configured to obtain the food item freshness data from the gas sensor and determine a freshness level for the food item based upon the food item freshness data. The food item freshness server may also be configured to communicate a notification to the remote device based upon the freshness level.

A gas sensor includes a gas detecting element that includes a first electrode, a metal oxide layer, and a second electrode; and a first insulating film that has an opening allowing the second electrode to be partially exposed therethrough and covers the first electrode, the metal oxide layer, and another part of the second electrode. The metal oxide layer has a characteristic where its resistance value changes as the second electrode makes contact with gas molecules including hydrogen atoms. A first step is provided at a portion lying on an interface between the metal oxide layer and the second electrode and located within the opening as viewed in plan view. A local region is provided in the metal oxide layer and near the first step. A degree of oxygen deficiency of the local region is greater than a degree of oxygen deficiency of other regions in the metal oxide layer.

A microsensor and its method of manufacture are disclosed based on templated metal or metal oxide nanostructures. The microsensor includes an electrode that in one embodiment may be configured as a first sawtooth patterned electrode having a series of first peaks and first valleys and a second electrode that by be configured as a second sawtooth patterned electrode having a series of second peaks and second valleys where the second peaks generally align with the first peaks of the first electrode. A plurality of templated metal or metal oxide nanostructures connect on one side to the first electrode and on another side to the second electrode, where an electrical property of the microsensor changes in response to exposure to an environment to be monitored.

A sensor for sensing a gaseous analyte comprising semiconductor phononic nanowire structure and a micro-platform. The sensor comprises a thermal element sensitive to temperature and involving variously chemi-resistive, absorptive and phase change effects. Sensor readout includes monitoring the temperature of the micro-platform.

A detection system includes a power generation element; a first outer cover body enveloping the power generation element; a second outer cover body located between the power generation element and the first outer cover body, and enveloping the power generation element; a first space section enclosed by the first outer cover body and the second outer cover body; a second space section enclosed by the second outer cover body; and a detector that detects a gas in the first space section.

In one embodiment, a chemical sensor is described. The chemical sensor includes a chemically-sensitive field effect transistor including a floating gate conductor having an upper surface, a first opening extending through a first material and through a portion of a second material located on the first material and a second opening extending from the bottom of the first opening to the top of a liner layer located on the upper surface of the floating gate conductor.

The present teachings are generally directed to sensors that employ antibody- and/or aptamer-functionalized graphene layer (or graphene flakes and/or graphdiyne layer) for detecting a prostate-specific biomarker in a sample. A graphene layer can be deposited on a underlying substrate and functionalized with an antibody and/or aptamer that specifically binds with an analyte of interest (e.g., a prostate-specific biomarker). A sample under investigation can be introduced onto the functionalized graphene layer. The interaction of the analyte of interest, if present in the sample, with the functionalized graphene layer can mediate a change in at least one electrical property of the graphene layer, e.g., their DC electrical resistance. An analyzer can detect such a change and analyze it to determine whether the analyte is present in the sample. In some embodiments, calibration methods can be employed to quantify the analyte present in the sample.

A gas sensor that selectively detects and/or measures acetylene and/or ethylene includes a substrate; at least one electrode pair; at least one gas-sensitive layer consisting of at least one metal oxide from the group ReFeO.sub.3 and in contact with the at least one electrode pair; a heating element; and at least one control device, wherein the heating element is adapted to be heated alternately to at least two different temperatures of 150° C.-250° C., 200° C.-300° C. and 250° C.350° C., respectively, by the control device.

A hydrogen sulfide sensor includes a substrate, a par of interdigitated electrodes disposed on the substrate, and a homogeneous polyaniline sensing film disposed on the pair of interdigitated electrodes and having electrical conductivity that depends upon a concentration of hydrogen sulfide. A method for detecting hydrogen sulfide includes for each sensor of a plurality of sensors: generating a signal if said sensor is exposed to a sample of hydrogen sulfide having density greater than or equal to a hydrogen sulfide detection threshold of said sensor, wherein the plurality of sensors has a respective plurality of hydrogen sulfide detection limits that span a detection range. A method for forming a hydrogen sulfide sensor includes dissolving a polyaniline polymer and a metal-chloride salt in an organic solvent to form a solution, and spin-coating the solution to form a homogeneous sensing film disposed on a pair of interdigitated electrodes disposed on a substrate.

Systems and methods for removing ions from a sample (i.e., desalting) are generally described. In some embodiments, “desalting” comprises removing ions from a sample, the sample also comprising an analyte, such as a protein, a hormone, or an antigen. Unwanted ions can increase the noise when detecting or sensing a signal from an analyte within the sample.