Abstract: This specification discloses various improvements in the field of SPR sensing systems. One improvement relates to a portable SPR sensing system, e.g., a system contained within a suitcase that can be hand-carried to a monitoring site. Another improvement relates to a portable, cartridge-based SPR sensing system. In this system, selected portions of the system's electrical and fluidics systems are allocated between a base unit and a removable/disposable cartridge. Other improvements relate to methods or protocols for operating an SPR sensing system. Such methods provide for the elimination of false positives and increased sensitivity, e.g., by using secondary antibodies with specificity for different target epitopes and by sensor element redundancy. In addition, protocols are provided for the detection of small molecules.

Abstract: This specification discloses various improvements in the field of SPR sensing systems. One improvement relates to a portable SPR sensing system, e.g., a system contained within a suitcase that can be hand-carried to a monitoring site. Another improvement relates to a portable, cartridge-based SPR sensing system. In this system, selected portions of the system's electrical and fluidics systems are allocated between a base unit and a removable/disposable cartridge. Other improvements relate to methods or protocols for operating an SPR sensing system. Such methods provide for the elimination of false positives and increased sensitivity, e.g., by using secondary antibodies with specificity for different target epitopes and by sensor element redundancy. In addition, protocols are provided for the detection of small molecules.

Abstract: This specification discloses various improvements in the field of SPR sensing systems. One improvement relates to a portable SPR sensing system, e.g., a system contained within a suitcase that can be hand-carried to a monitoring site. Another improvement relates to a portable, cartridge-based SPR sensing system. In this system, selected portions of the system's electrical and fluidics systems are allocated between a base unit and a removable/disposable cartridge. Other improvements relate to methods or protocols for operating an SPR sensing system. Such methods provide for the elimination of false positives and increased sensitivity, e.g., by using secondary antibodies with specificity for different target epitopes and by sensor element redundancy. In addition, protocols are provided for the detection of small molecules.

Abstract: This specification discloses various improvements in the field of SPR sensing systems. One improvement relates to a portable SPR sensing system, e.g., a system contained within a suitcase that can be hand-carried to a monitoring site. Another improvement relates to a portable, cartridge-based SPR sensing system. In this system, selected portions of the system's electrical and fluidics systems are allocated between a base unit and a removable/disposable cartridge. Other improvements relate to methods or protocols for operating an SPR sensing system. Such methods provide for the elimination of false positives and increased sensitivity, e.g., by using secondary antibodies with specificity for different target epitopes and by sensor element redundancy. In addition, protocols are provided for the detection of small molecules.

Abstract: SPR sensors and multisensors having capillary geometry. Sensors have a capillary substrate in which at least a portion of the inside surface of the capillary is provided with an SPR-sensing area. Samples for analysis are introduced into the capillary cavity. SPR is measured by radially illuminated the capillary SPR-sensing area with light having a TM-polarized component. Light reflected from the SPR-sensing area exiting radially from the capillary is detected at selected angles to obtain reflectivity as a function of incidence angle to determine RI of the sample in the vicinity of the SPR-sensing area. The capillary geometry is readily adaptable to simultaneous measurement of several optical properties of a given sample in addition to SPR by radial and/or axial illumination of the sample. Multisensors with capillary geometry which simultaneously measure SPR and bulk RI are provided.

Abstract: The present invention provides SPR sensors in which the sensing element is a planar lightpipe. The sensors of this invention include configurations which employ multiwavelength light incident on the SPR sensing area at a single angle or at a range of angles. Sensors of this invention also include configurations that employ monochromatic light at a range of angles. Many of the configurations of the SPR lightpipe sensors of this invention involve imaging of input light through the lightpipe. In one embodiment, the invention provides a first order SPR sensor system in which the sensing element is a planar lightpipe. Light coupled into the lightpipe reflects off an SPR sensing area positioned on an external surface planar surface of the lightpipe.

Abstract: This disclosure describes new methods and devices for sensing redox-active analytes in solution. The invention combines a surface plasmon resonance (SPR) sensor and a chemical electrode sensor. A conducting layer which supports SPR is attached to a voltage source. The voltage source is also connected to a reference electrode, which is in the aqueous solution with the SPR sensor. As the voltage is varied, the analytes undergo oxidation and reduction at the surface of the conducting film. The current is measured, just as it would be in a standard chemical electrode, with current peaks appearing at different potentials indicating different ions in the solution. Unlike a standard chemical electrode, the surface of the conducting film is also used to excite a surface plasmon wave (SPW). The SPW provides new information which is not available from any standard chemical electrode, such as the effective index of refraction at the surface of the conducting film as the analytes are being oxidized and/or reduced.

Abstract: There is disclosed fiber optic sensor which detects a sample in contact with the sensor by surface plasmon resonance (SPR) measurements, as well as methods and apparatus relating thereto. The fiber optic SPR sensor of this invention employs a limited range of incident angles and uses incident light having multiple wavelengths. In preferred embodiments, both an in-line transmission-based fiber optic SPR sensor and a terminated reflection-based fiber optic SPR sensor are disclosed. The fiber optic SPR sensor includes a surface plasmon supporting metal layer in contact with an exposed portion of the optical fiber core, and may optionally contain one or more additional layers deposited on the surface plasmon supporting metal layer.

Abstract: The present invention relates in general to SPR sensors in which the sensing element is a planar lightpipe. More specifically, a planar lightpipe sensor configuration for measurement of SPR at a single angle operation is provided. The lightpipe of this sensor is beveled to facilitate coupling of substantially collimated white light, preferably TM polarized white light, at a selected single angle that excites SPR at the sensing area. Angle of incidence on the SPR sensing area is determined by bevel angle used. This embodiment is a zero order sensor in the sense that it allows measurement for a given analyte at only a single angle of incidence. In this embodiment, however, the lightpipe can have a plurality of SPR sensing area across its width to provide for multichannel sensing. Refractive index sensitivity of this configuration is estimated as 4.times.10.sup.-5 RI units.

Abstract: The present invention provides SPR sensors in which the sensing element is a planar lightpipe. The sensors of this invention include configurations that employ multi-wavelength light (including broad band and white light) incident on the SPR sensing area at a single angle or at a range of angles. Sensors and probes of this invention also include configurations that employ monochromatic light at a range of angles. Many of the configurations of the SPR lightpipes of this invention involve imaging of input light through the folded lightpipe. In one general embodiment, the invention provides a SPR sensor system in which the sensing element is a folded planar lightpipe.

Abstract: There is disclosed fiber optic sensor which detects a sample in contact with the sensor by surface plasmon resonance (SPR) measurements, as well as methods and apparatus relating thereto. The fiber optic SPR sensor of this invention employs a limited range of incident angles and uses incident light having multiple wavelengths. In preferred embodiments, both an in-line transmission-based fiber optic SPR sensor and a terminated reflection-based fiber optic SPR sensor are disclosed. The fiber optic SPR sensor includes a surface plasmon supporting metal layer in contact with an exposed portion of the optical fiber core, and may optionally contain one or more additional layers deposited on the surface plasmon supporting metal layer.

Abstract: A power diode having substantially no reverse-recovery time and relatively high conductance. The power diode is a majority carrier semiconductor having a structure that is similar to that of a metal oxide semiconductor field effect transistor (MOSFET), in that it includes a source, a drain, a gate, and a body. In one embodiment, to increase conductance of the power diode, a linked-cell configuration that reverses the geometry of a conventional cell-type MOSFET is employed, thereby increasing the width of a conductance channel over that of a conventional MOSFET, and compensating for a relatively low level of inversion in the channel region. Negative and positive feedback circuits are used to further improve the conductance of the power diode by dynamically setting a bias voltage applied between the gate and the source to a level just below a threshold voltage.

Abstract: There is disclosed fiber optic sensor which detects a sample in contact with the sensor by surface plasmon resonance (SPR) measurements, as well as methods and apparatus relating thereto. The fiber optic SPR sensor of this invention employs a limited range of incident angles and uses incident light having multiple wavelengths. In preferred embodiments, both an in-line transmission-based fiber optic SPR sensor and a terminated reflection-based fiber optic SPR sensor are disclosed. The fiber optic SPR sensor includes a surface plasmon supporting metal layer in contact with an exposed portion of the optical fiber core, and may optionally contain one or more additional layers deposited on the surface plasmon supporting metal layer.

Abstract: A liquid junction electrode 10 formed from a silicon body 14 and having a glass membrane 22 attached thereto. A reference electrode is constructed by forming the glass membrane 22 from porous glass having a preferable pore size in the range of 40 angstroms to 75 angstroms. The porous glass membrane 22 has a coating 24 of glass containing mobile ions that is electrostatically bonded to the silicon body 14. Alternatively, a glass plug 92 is formed from a paste of ground glass and organic binder that is heated to cause formation of pores and bonding of the glass plug 92 to a silicon body 94. An ion-sensitive electrode is constructed by forming the membrane 52 from an ion-sensitive glass or by filling the pores of the porous glass membrane 22 with an ion-sensitive material.

Abstract: An improved ion-sensitive electrode is described, particularly in terms of the structure of a pH electrode and first and second processes for making the same. The pH electrode includes a substrate, preferably of forsterite, which is configured as a wafer having a substantially planar wafer surface. A continuous conducting layer, formed by either thin-film vapor deposition or thick-film screening processes, is formed on the substantially planar wafer surface in a desired configuration. A first region of the continuous conducting layer, and contiguous portions of the substantially planar wafer surface, are covered by a continuous membrane layer preferably composed of a pH-sensitive glass such as Corning Code 0150 glass.