Hitachi Electronics Engineering Co., Ltd.

Hitachi, Ltd.

Hitachi Software Engineering Company, Ltd.

Hiroaki Machida

Hideki Kambara

Keiichi Nagai

Takashi Anazawa

Mitsuyoshi Koizumi

Hisanori Nasu

Yuusuke Miyazaki

Yusuke Miyazaki

Yoshinori Mishina

Shinichi Takagi

A DNA base sequencer including a gel electrophoretic means having tracks for electrophoresing fluorophore-labelled DNA fragments, a laser diode as a light source for illuminating said tracks with exciting laser light and a CCD sensor for detecting the fluorescence emitted from the illuminated DNA fragments, the laser diode has a control unit including a Peltier device for controlling the temperature of the laser diode, a Peltier device temperature setting generating means having a processor and a memory, and a temperature control circuit that generates a drive current to the Peltier device for controlling its temperature. The CCD sensor receives part of the exciting light from the laser diode as stray light and detects its wavelength. The Peltier device temperature setting generating means is such that, in accordance with the wavelength of stray light as detected periodically with said CCD sensor according to the program stored in said memory, it calculates a corrective value that adjusts the detected wavelength of stray light to the desired wavelength of exciting light that corresponds to the desired temperature setting and that an appropriate temperature setting signal is generated on the basis of said corrective value and the desired temperature setting and sent to the Peltier device temperature control circuit.

DNA base sequencer

An electrophoresis separation and detection apparatus for separating and detecting fluorophore-labeled samples by electrophoresis, which comprises a migrating and separating means for electrophoresis separation of the samples labeled with two or more kinds of fluorophore labels, respectively; an irradiating means which casts two or more kinds of exciting lights having different wavelengths on a plurality of positions in all the electrophoresis lanes or on the extensions of all the electrophoresis lanes substantially at the same time; and a detecting means which detects the samples separated by the electrophoresis, at the positions on which the exciting lights are casted, wherein each fluorophore label is composed of a substance for excitation which is excited by the exciting light and a substance for emission which emits light owing to energy transfer from the substance for excitation; two or more kinds of substances are used as each of the substance for excitation and the substance for emission; and the detecting means detects the samples by distinguishing the two or more kinds of the fluorophore labels from one another on the basis of the difference of combination of the two or more kinds of the substances used as the substance for excitation and those used as the substance for emission.

Method and apparatus for electrophoresis separation and detection

The improved DNA base sequencer comprising an electrophoresis plate having a gel electrolyte layer held between two glass plates, one of which is partially cut away on the top edge in the direction of width, an assay compartment for accommodating said electrophoresis plate in a vertically erect position, a lower reservoir of a buffer solution in which the lower part of the gel electrolyte layer in the electrophoresis plate is to be immersed, an upper reservoir of a buffer solution in which the upper part of said electrolyte layer is to be immersed, photoexciting laser light applying means by which laser light is emitted from a lateral side of the electrophoresis plate in such a way that it crosses the lanes in said plate at right angles, and fluorescence detecting means by which the fluorescence emitted from a DNA fragment illuminated with the laser light is picked up and converted to an electric signal, and the apparatus is characterized in that a sharkstoothcomb made of a water-swellable material is inserted from the top edge of said electrophoresis plate into the space between the two glass plates, either the top or bottom edge of said sharkstoothcomb being provided with a plurality of teeth which are each tapered from the root toward the tip. Using this apparatus, samples can be easily and yet positively injected at specified lane positions on the gel electrolyte layer.

In the multi-color fluorescence detection type electrophoresis apparatus provided with the electrophoresis gel plate, excitation laser source, means to separate the fluorescence images according to each emission wavelength, and the detector of the fluorescence subjected to wavelength selection, two or more laser sources are provided, each of laser lights is irradiated on the sample on a time-sharing basis, and the filter which cuts off the scattered light of each the laser synchronous with the laser beam is installed in front of the wavelength separation means thereby providing simultaneous, quick and real-time analysis of a great number of samples such as DNA and RNA labeled by many types of fluorophores, without overlapping the wavelengths of the excitation light and the fluorescence.

Fluorescence detection type electrophoresis apparatus

Growing community of inventors

Saitama-ken, Japan

Hiroaki Machida