Abstract: A sample cell apparatus for use in spectroscopic determination of an analyte in a body fluid sample includes a first plate member and a second plate member made from an optically clear material. A channel extending into a surface of the first plate member and an opposing surface of the second plate member houses a floating seal, which surrounds a fluid sample chamber. The fluid chamber is closed to define a repeatable optical path-length therethrough by urging the first plate member against the second plate member without compressing the floating seal between the first plate member and the second plate member. The seal channel is vented to prevent fluid pressure from flexing the first plate member or the second plate member. An actuator having an extended foot portion extends over the fluid chamber to help prevent flexing of the first plate member or the second plate member.

Abstract: Analyte content in a cell free portion of a body fluid, such as blood, is optically determined without centrifugation or other preliminary steps for separating the cell free portion from the body fluid. A channel is configured for containing a flowing sample of the body fluid along an optical boundary. The channel is configured so that a cell free layer of the fluid naturally forms along the boundary of the channel which coincides with the optical boundary. A light source is directed onto the optical boundary at an angle selected to generate total reflection from the boundary and to generate an evanescent field across the boundary in the cell free layer of fluid. A light detector is configured to detect absorption of the light in the evanescent field. The light source and light detector are matched to the wavelength range of an absorption peak of the analyte being detected.

Abstract: A sample cell apparatus for use in spectroscopic determination of an analyte in a body fluid sample includes a first plate member made from an optically clear material and a second plate member made from an optically clear material and opposing the first plate member. A channel extending into a surface of the first plate member and an opposing surface of the second plate member houses a floating seal. The floating seal surrounds a fluid chamber that retains a sample of body fluid for optical measurement. The fluid chamber may be opened for flushing by separating the first plate member from the second plate member. During measurements the fluid chamber is closed to define a repeatable optical path-length therethrough by urging the first plate member against the second plate member without compressing the floating seal between the first plate member and the second plate member.

Abstract: This invention relates to an optical system and method for performing turbidity assay, e.g. coagulation of blood or plasma, comprising a standard optical reference, a sample handling structure, a light source and an optical detection unit. The standard optical reference, such as a fluorophore-doped glass, provides constant optical signal under controlled optical conditions. The sample handling structure, such as a microfluidic system with reaction chamber, can be placed beneath or above the standard optical reference. During operation, the coagulating plasma/blood changes its optical absorbance and reflection properties, which results in changes in optical signal that reaches the optical reading unit. The variation of the optical signal, such as fluorescence signal indicates the kinetics of the turbidity varying process, such as plasma/blood coagulation process.

Abstract: A bioserisor platform is configured with upconverting nanoparticles on the surface of a resonant grating structure with enhanced sensitivity. The grating structure is illuminated with a light beam at one of its resonance modes to form a strong evanescent field at the surface and used for high sensitivity assays. The strong evanescent field triggers the upconverting nanoparticles to generate enhanced and localized emission on the grating surface, with lower background and lower auto-fluorescence from the grating substrate. This leads to improved performance in detecting analytes in bioassays.