Visible Genetics Inc.

John A Renfrew

Paul Waterhouse

John K Stevens

Henryk Zaleski

James W Cassidy

Eric Steinbach

Alexandre M Izmailov

Stuart MacMillan

James M Dunn

James Leushner

Electrophoresis gels are formed using a gel-forming insert having a beveled edge which results in loading sites having a beveled bottom surface. The gel forming insert can have a continuous beveled edge across the entire width of the gel, in which case a special loading insert is used which matches the bevel of the gel. Alternatively, the gel forming insert may be formed with a plurality of fingers with beveled ends, each finger defining a well in the gel. In one form of the gel-forming insert, the fingers are formed from a soft, flexible polymer such as silicone applied on a rigid support.

Gel-forming insert for electrophoresis gels

A high dynamic range apparatus for separation and detection of polynucleotide fragments has a housing adapted to receive an electrophoresis gel holder containing an electrophoresis gel loaded with fluorophore-labeled samples; one or more laser diodes for providing radiation of a frequency suitable for excitation of the fluorophore which irradiates a an array of excitation/detection sites on the electrophoresis gel; an array of detectors aligned with the excitation/detection sites for collecting fluorescent emissions; and one or more components for increasing the dynamic range of the instrument by at least an order of magnitude. These components, which can be used individually or in combination include detectors that are connected to a signal processing system that modulates the period of signal integration employed so that large signals are totaled at short time intervals and smaller signals are totaled at longer time intervals; the use of a beam splitter to produces a high intensity beam of emitted light and a low intensity beam of emitted light from each excitation/detection site; and a device for modulating the intensity of the excitation beam can be used to improve the dynamic range of the instrument.

High dynamic range apparatus for separation and detection of

Apparatus for preparing gels for use in electrophoretic separations and

Automated electrophoresis and fluorescence detection apparatus and method

An apparatus and method for thermally cycling a reaction mixture in a reaction vessel to expose the mixture to the varying temperatures necessary to, for example, achieve PCR amplification or the preparation of sequencing fragments using a cycle sequencing operation makes use of flow-through reaction vessels, such as capillary tubes, for the preparation and thermal cycling of reaction mixtures. In order to prevent loss of the reaction mixture from the vessels during heating, the thermal cycling apparatus of the invention provides means for sealing the proximal and distal end of each reaction vessel. The proximal ends can be sealed by coupling to a pump which permits movement of the samples within the reaction vessels. As to the distal ends, the reaction vessels can be sealed by pressing the distal end of each vessel against a sealing element with a conformable surface, or by immersing the distal end of each vessel in the reservoir of liquid, preferably of an oil, that is not miscible with the reaction mixture.

Method and apparatus for thermal cycling and for automated sample

Microgels for use in medical diagnosis and methods of making and using

An improved electrophoresis and fluorescence detection method for nucleotide sequences comprises a fluorescence sensing region along the path of nucleotide detection, coupled with amplification and integration in an integrator of output signals in the form of activity peaks. The output signal, which is converted to a voltage signal, is summed with a programmable offset generated by an inexpensive eight-bit D/A converter. The offset signal is selected to establish a lower starting point for the dynamic range of analog-digital conversion, and is selected to null some or all of the background fluorescence level. The integrator is switchable under program control. The integrator is switched on for long and short integration intervals. The short intervals permit sensing over a dynamic range accommodating very high levels of fluorescence; very high peaks may be measured and features of the peaks distinguished. The long intervals permit sensing over a dynamic range that is optimized for the peaks associated with the smaller peaks of individual nucleotides. In this way, the dynamic range of the analog-digital conversion permits the highest possible resolution over the range of interest during the time in which the sequencing of the nucleotides takes place. The method of nucleotide sequencing and analysis is fast, economical, and yields data with high resolution.

Electrophoresis and fluorescence detection method

An improved electrophoresis and fluorescence detection apparatus has an electromagnetic radiation sensor juxtaposed with a sensing region. The output signal from the electromagnetic radiation sensor is a current signal, and the current signal is converted to a voltage signal. The voltage signal is summed with a programmable offset generated by an inexpensive eight-bit D/A converter. The offset signal is selected to establish a lower starting point for the dynamic range of the A/D conversion, and is selected to null some or all of the background electromagnetic radiation level. The summed signal is amplified and integrated in an integrator. The integrator is switchable under program control. The integrator is switched on for long and short intervals. The short intervals permit sensing over a dynamic range accommodating very high levels of fluorescence; very high peaks may be measured and features of the peaks distinguished. The long intervals permit sensing over a dynamic range that is optimized for the peaks associated with the smaller peaks of individual nucleotides. In this way, the dynamic range of the A/D convertor is set to permit the highest possible resolution over the range of interest during the time in which the sequencing of the nucleotides takes place. The sequencer is fast and economical and yields data with high resolution.

Electrophoresis and fluorescence detection apparatus

Improved detection methods and apparatus which may be used individually or in various combinations enhance the ability of the electrophoresis apparatus to detect fluorophore-labeled materials in short periods of time. One such apparatus comprises a housing adapted to receive an electrophoresis gel holder; an excitation source of electromagnetic radiation having a frequency effective to induce emission of electromagnetic radiation from the fluorophore; a plurality of optical fibers for delivering electromagnetic radiation from the excitation source to a linear array of excitation/detection sites on the gel holder, optical switching means for sequentially directing electromagnetic radiation into one of several pre-defined groups of the optical fibers; detection means such as a photomultiplier tube, or an array of photomultiplier tubes for detecting emission from the fluorophore induced by a radiation from the excitation source; and means for correlating a detected emission with the switching of the excitation electromagnetic radiation such that a given emission may be linked with the excitation/detection site being irradiated.

An electrophoresis microgel is formed in a gel holder. The gel holder comprises a top substrate, a bottom substrate and a spacer disposed between the top substrate and the bottom substrate. The spacer establishes a separation of from 25 to 250 microns between the top substrate and the bottom substrate. A gel compartment is formed by partially sealing the top substrate to the bottom substrate, while leaving an opening for the introduction of unpolymerized gel. The gel compartment is then filled with an unpolymerized gel, which is polymerized in the gel compartment. Electrodes may be printed on the substrates, may be contacts to an exposed edge of gel, or may be applied through windows cut into one of the substrates. One type of gel holder makes use of graded beads having a diameter of 25 to 250 microns slurried in an adhesive such as an acrylate adhesive as the spacer. The slurry is printed onto the surface of one or both substrates to form a spacer of the desired shape, and then hardened using heat or light. If desired, the spacer can establish lanes within the gel.

Microgels for use in medical diagnosis and holders useful in fabricating

An apparatus for the rapid filling and polymerization of electrophoresis gels comprises:

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Burlington, Canada

John A Renfrew