Abstract: An asymmetric sensor having asymmetric electrodes and/or being asymmetrically anchored provides enhanced sensitivity. In example embodiments, part of the electrode on a sensor is etched or removed resulting in enhanced mass-change sensitive resonant modes. In another example embodiment, a sensor is anchored asymmetrically, also resulting in enhanced mass-change sensitive resonant modes. By asymmetrically anchoring a piezoelectric portion of a sensor, resonant bending modes of the sensor can be measured electrically without external instrumentation. Modifying the electrode of a piezoelectric cantilever enables expression of mass-change sensitive resonant modes that normally do not lend themselves to electrical measurement.

Abstract: Detection of miniscule amounts of nucleic acid is accomplished via binding of target nucleic acid to probe material, composed of nucleic acid, which is bound to a sensor configured to sense mass. The sensor is prepared by immobilizing a probe material to a surface of the sensor, wherein the probe material is known to bind to the target nucleic acid. The prepared sensor is exposed to the target nucleic acid. The target nucleic acid binds to the probe material. The mass accumulated on the sensor reflects the amount of target nucleic acid bound to the probe material.

Abstract: A novel dual mode sensor may combine mass-sensing measurements of dynamic-mode cantilevers with electrochemical impedance spectroscopy employed for transduction in sensitive electrochemical biosensors. The integrated design of the sensor may provide simultaneous and continuous measurement of resonant frequency shift and charge transfer resistance of a target analyte bound to a surface of the sensor. Binding of a target analyte to the surface of the sensor may cause charge transfer resistance to increase and the resonant frequency of the sensor to decrease. These simultaneous dynamic modes of the sensor may be utilized to measure an amount of mass of the target analyte accumulated on the surface of the sensor and to reduce and/or eliminate false negative measurement results.

Abstract: Cantilever Sensors made of piezoelectric material may be structured with various configurations of asymmetric anchors as well as asymmetric electrodes. Such asymmetry enables measurement of resonant properties of the cantilever that are otherwise unmeasurable electrically, resulting in significant advantages for ease of measurement. In addition the asymmetry enables expression of torsional and/or lateral modes that are otherwise absent, and these modes also exhibit excellent mass-change sensitivity. The asymmetries may enable resonant mode impedance-coupling.

Abstract: A change in impedance of a electromechanical resonating sensor is utilized to detect and/or measure a change in mass accumulated on the sensor. The impedance is monitored at a fixed frequency. The fixed frequency may be at or near the resonance frequency of the sensor. In various configurations, the sensor comprises a quartz crystal microbalance sensor or a piezoelectric cantilever sensor.

Abstract: Flow cells configured for piezoelectric millimeter-sized cantilever sensors provide direct, sensitive detection of analytes in fluid media. The flow cells comprise a flow inlet and a flow outlet positioned to cause sample flow past a sensing surface of the cantilever sensor. The flow cell is configured for millimeter-sized cantilever sensors. The geometry of the flow cell influences the sample flow and thus the interaction of the flow with the cantilever sensor.

Abstract: Detection of miniscule amounts of nucleic acid is accomplished via binding of target nucleic acid to probe material, composed of nucleic acid, which is bound to a sensor configured to sense mass. The sensor is prepared by immobilizing a probe material to a surface of the sensor, wherein the probe material is known to bind to the target nucleic acid. The prepared sensor is exposed to the target nucleic acid. The target nucleic acid binds to the probe material. The mass accumulated on the sensor reflects the amount of target nucleic acid bound to the probe material.

Abstract: Detection of miniscule amounts of nucleic acid is accomplished via binding of target nucleic acid to probe material, composed of nucleic acid, which is bound to a sensor configured to sense mass. The sensor is prepared by immobilizing a probe material to a surface of the sensor, wherein the probe material is known to bind to the target nucleic acid. The prepared sensor is exposed to the target nucleic acid. The target nucleic acid binds to the probe material. The mass accumulated on the sensor reflects the amount of target nucleic acid bound to the probe material.

Abstract: A piezoelectric cantilever sensor includes a piezoelectric layer and a non-piezoelectric layer, a portion of which is attached to the piezoelectric layer. In one embodiment, one end of the non-piezoelectric layer extends beyond the end of piezoelectric layer to provide an overhang. The overhang piezoelectric cantilever sensor enables increased sensitivity allowing application of the device in more viscous environments, such as liquid media, as well as application in liquid media at higher flow rates than conventional piezoelectric cantilevers. In another embodiment, the sensor includes first and second bases and at least one of the piezoelectric layer and the non-piezoelectric layer is affixed to each of the first and second bases to form the piezoelectric cantilever sensor. In this embodiment, the sensor is robust and exhibits excellent sensing characteristics in both gaseous and liquid media, even when subjected to relatively high flow rates.

Abstract: An asymmetric sensor having asymmetric electrodes and/or being asymmetrically anchored provides enhanced sensitivity. In example embodiments, part of the electrode on a sensor is etched or removed resulting in enhanced mass-change sensitive resonant modes. In another example embodiment, a sensor is anchored asymmetrically, also resulting in enhanced mass-change sensitive resonant modes. By asymmetrically anchoring a piezoelectric portion of a sensor, resonant bending modes of the sensor can be measured electrically without external instrumentation. Modifying the electrode of a piezoelectric cantilever enables expression of mass-change sensitive resonant modes that normally do not lend themselves to electrical measurement.

Abstract: A piezoelectric cantilever sensor includes a piezoelectric layer and a non-piezoelectric layer, a portion of which is attached to the piezoelectric layer. In one embodiment, one end of the non-piezoelectric layer extends beyond the end of piezoelectric layer to provide an overhang. The overhang piezoelectric cantilever sensor enables increased sensitivity allowing application of the device in more viscous environments, such as liquid media, as well as application in liquid media at higher flow rates than conventional piezoelectric cantilevers. In another embodiment, the sensor includes first and second bases and at least one of the piezoelectric layer and the non-piezoelectric layer is affixed to each of the first and second bases to form the piezoelectric cantilever sensor. In this embodiment, the sensor is robust and exhibits excellent sensing characteristics in both gaseous and liquid media, even when subjected to relatively high flow rates.

Abstract: The concentration of a material covering a surface is controlled via an equilibrium process. Equilibrium parameters such as a concentration of the provided material, the exposure time of the material to the surface, and the surface area of an attractor applied to the surface are determined utilizing a millimeter sized piezoelectric cantilever sensor. In an example embodiment, the material is provided at a low concentration to the surface until equilibrium is attained. The amount of material accumulated on the surface is determined utilizing the cantilever sensor. The surface area of the attractor and the measured amount of material are utilized to determine the amount of the attractor surface area having the material bound thereto. Knowledge of the equilibrium parameters allows controlled surface coverage of the material on the attractor for any application. The concentration of the material adsorbed on the surface is precisely determinable and repeatable.

Abstract: Extremely minute amounts of live pathogens are rapidly detected using a piezoelectric cantilever sensor. A single pathogen is detectable in about 30 minutes. Pathogen-specific antibodies are immobilized on the sensor surface. The sensor is exposed to a medium that potentially contains the target pathogen. When target pathogens are contained in the medium, both dead and live pathogen cells bind to the immobilized antibody on the sensor surface. The attached target pathogen cells are exposed to a pathogen discriminator capable of discriminating between live cells and dead cells by increasing the mass of live cells. Example pathogens include Escherichia coli, Listeri monocytogene, and Salmonella enteritidis. Example antibodies include those that bind to the pathogenic bacteria designated as ATCC 43251, ATCC 700375, and ATCC 31194. Example pathogen discriminators include intracellular pH indicating molecules.

Abstract: A method for detection of airborne biological agent using a piezoelectric cantilever sensor that includes a piezoelectric layer and a non-piezoelectric layer. A recognition entity is placed on one or both of the two layers. The antibody that recognizes and binds to the airborne species may be chemically immobilized on the cantilever sensor surface. In one embodiment, the cantilever sensor is attached to a base at only one end. In another embodiment, the sensor includes first and second bases and at least one of the piezoelectric layer and the non-piezoelectric layer is affixed to each of the first and second bases to form a piezoelectric cantilever beam sensor. In this embodiment, resonance is measured via stress on the piezoelectric layer and it has been demonstrated that such sensors are robust and exhibit excellent sensing characteristics in gaseous media with sufficient sensitivity to detect airborne species at relatively low concentrations.

Abstract: A method for detection of airborne biological agent using a piezoelectric cantilever sensor that includes a piezoelectric layer and a non-piezoelectric layer. A recognition entity is placed on one or both of the two layers. The antibody that recognizes and binds to the airborne species may be chemically immobilized on the cantilever sensor surface. In one embodiment, the cantilever sensor is attached to a base at only one end. In another embodiment, the sensor includes first and second bases and at least one of the piezoelectric layer and the non-piezoelectric layer is affixed to each of the first and second bases to form a piezoelectric cantilever beam sensor. In this embodiment, resonance is measured via stress on the piezoelectric layer and it has been demonstrated that such sensors are robust and exhibit excellent sensing characteristics in gaseous media with sufficient sensitivity to detect airborne species at relatively low concentrations.

Abstract: Quantification of a target analyte is performed using a single sample to which amounts of the target analyte are added. Calibration is performed as part of quantification on the same sample. The target analyte is detectable and quantifiable using label free reagents and requiring no sample preparation. Target analytes include biomarkers such as cancer biomarkers, pathogenic Escherichia coli, single stranded DNA, and staphylococcal enterotoxin. The quantification process includes determining a sensor response of a sensor exposed to the sample and configured to detect the target analyte. Sensor responses are determined after sequential additions of the target analyte to the sample. The amount of target analyte detected by the sensor when first exposed to the sample is determined in accordance with the multiple sensor responses.

Abstract: A piezoelectric cantilever sensor includes a piezoelectric layer and a non-piezoelectric layer, a portion of which is attached to the piezoelectric layer. In one embodiment, one end of the non-piezoelectric layer extends beyond the end of piezoelectric layer to provide an overhang. The overhang piezoelectric cantilever sensor enables increased sensitivity allowing application of the device in more viscous environments, such as liquid media, as well as application in liquid media at higher flow rates than conventional piezoelectric cantilevers. In another embodiment, the sensor includes first and second bases and at least one of the piezoelectric layer and the non-piezoelectric layer is affixed to each of the first and second bases to form the piezoelectric cantilever sensor. In this embodiment, the sensor is robust and exhibits excellent sensing characteristics in both gaseous and liquid media, even when subjected to relatively high flow rates.

Abstract: A piezoelectric cantilever sensor includes a piezoelectric layer and a non-piezoelectric layer, a portion of which is attached to the piezoelectric layer. In one embodiment, one end of the non-piezoelectric layer extends beyond the end of piezoelectric layer to provide an overhang. The overhang piezoelectric cantilever sensor enables increased sensitivity allowing application of the device in more viscous environments, such as liquid media, as well as application in liquid media at higher flow rates than conventional piezoelectric cantilevers. In another embodiment, the sensor includes first and second bases and at least one of the piezoelectric layer and the non-piezoelectric layer is affixed to each of the first and second bases to form the piezoelectric cantilever sensor. In this embodiment, the sensor is robust and exhibits excellent sensing characteristics in both gaseous and liquid media, even when subjected to relatively high flow rates.

Abstract: A piezoelectric cantilever sensor includes a piezoelectric layer and a non-piezoelectric layer, a portion of which is attached to the piezoelectric layer. In one embodiment, one end of the non-piezoelectric layer extends beyond the end of piezoelectric layer to provide an overhang. The overhang piezoelectric cantilever sensor enables increased sensitivity allowing application of the device in more viscous environments, such as liquid media, as well as application in liquid media at higher flow rates than conventional piezoelectric cantilevers. In another embodiment, the sensor includes first and second bases and at least one of the piezoelectric layer and the non-piezoelectric layer is affixed to each of the first and second bases to form the piezoelectric cantilever sensor. In this embodiment, the sensor is robust and exhibits excellent sensing characteristics in both gaseous and liquid media, even when subjected to relatively high flow rates.

Abstract: The techniques described herein are directed to removing material that has attached to or preventing material from attaching to the surface of a piezoelectric cantilever. The material can be a target material, other, non-target, material that may be weakly bound or attached to the cantilever sensor, or the material may be a combination thereof. Accordingly, the cantilever sensor can be reused, in situ, without degraded detection performance of the cantilever sensor. The techniques may also be utilized to remove all material that has attached to a surface of the cantilever sensor which provides means for reusing the cantilever sensor.