Abstract: A method of separating components having a given negative or positive charge and contained in a sample is disclosed. The method involves, in one embodiment, loading a microchannel with a sample, placed between a trailing-edge electrolyte having a selected concentration of a titratable species, and a leading-edge electrolyte.

Abstract: Devices are provided comprising reflecting channels for directing horizontally a vertical light beam through a multiplicity of streams. The devices provide particular applications in microfluidics, where streams of narrow cross-sectional dimensions are involved. Desirably, channels having 45° walls are provided for directing the beams and where the streams are divided by walls, the walls are at substantially 90°. Methods of fabrication of the devices are provided.

Abstract: A method and device for injecting a liquid sample into an electrolyte channel in a microfluidics device is disclosed. The device has a channel network that includes an electrolyte channel having upstream and downstream channel portions and first, second, and third side channels that intersect the electrolyte channel between the two channel portions at first, second, and third ports, respectively. In the method, a sample is moved electrokinetically into the electrolyte channel, to form a defined sample volume therein. By simultaneously controlling the voltage applied to the three side channels, and at least one of the upstream and downstream channel end portions, the sample volume element can be shaped to have a desired leading- and trailing-edge shape and/or distribution of sample components within the volume elements.

Abstract: A microfabricated device for electrokinetically moving biological and chemical samples includes a detection chamber for receiving a plurality of adjacent sample streams to be detected. The device includes a plurality of adjacent input channels fluidly connected to the detection chamber and each of the input channels is fluidly connected to the detection chamber via an enlarged end section. The enlarged end section may be an expanding taper having its widest end at the detection chamber. The taper may further be linear or parabolic shaped, or the taper may have other shapes. The novel enlarged end section provides for the plurality of adjacent sample streams to enter the detection chamber and remain substantially discrete for at least a threshold distance through the detection chamber. Accordingly, lateral diffusion of the samples is minimized. The microfabricated device may also feature a plurality of tapered junctions each of which is interposed between adjacent input channels.

Abstract: A method of separating components having a given negative or positive charge and contained in a sample is disclosed. The method involves, in one embodiment, loading a microchannel with a sample, placed between a trailing-edge electrolyte having a selected concentration of a titratable species, and a leading-edge electrolyte.

Abstract: A method of separating components having a given negative or positive charge and contained in a sample is disclosed. The method involves, in one embodiment, loading a microchannel with a sample, placed between a trailing-edge electrolyte having a selected concentration of a titratable species, and a leading-edge electrolyte.

Abstract: A method of separating components having a given negative or positive charge and contained in a sample is disclosed. The method involves, in one embodiment, loading a microchannel with a sample, placed between a trailing-edge electrolyte having a selected concentration of a titratable species, and a leading-edge electrolyte.

Abstract: A method and device for injecting a liquid sample into an electrolyte channel in a microfluidics device is disclosed. The device has a channel network that includes an electrolyte channel having upstream and downstream channel portions and first, second, and third side channels that intersect the electrolyte channel between the two channel portions at first, second, and third ports, respectively. In the method, a sample is moved electrokinetically into the electrolyte channel, to form a defined sample volume therein. By simultaneously controlling the voltage applied to the three side channels, and at least one of the upstream and downstream channel end portions, the sample volume element can be shaped to have a desired leading- and trailing-edge shape and/or distribution of sample components within the volume elements.

Abstract: A technique for increasing the excitation and collection of evanescent fluorescence radiation emanating from a fiber optic sensor having a high refractive index (nr), dielectric thin film coating has been disclosed and described. The invention comprises a clad optical fiber core whose cladding is removed on a distal end, the distal end coated with a thin, non-porous, titanium dioxide sol-gel coating. It has been shown that such a fiber will exhibit increased fluorescence coupling due in part by 1) increasing the intensity of the evanescent field at the fiber core surface by a constructive interference effect on the propagating light, and 2) increasing the depth of penetration of the field in the sample. The interference effect created by the thin film imposes a wavelength dependence on the collection of the fluorescence and also suggests a novel application of thin films for color filtering as well as increasing collected fluorescence in fiber sensors.