Chemistry: molecular biology and microbiology – Micro-organism – tissue cell culture or enzyme using process... – Preparing compound containing saccharide radical
Reexamination Certificate
2000-10-23
2002-04-02
Horlick, Kenneth R. (Department: 1656)
Chemistry: molecular biology and microbiology
Micro-organism, tissue cell culture or enzyme using process...
Preparing compound containing saccharide radical
C435S283100, C435S006120, C422S105000, C422S068100
Reexamination Certificate
active
06365378
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a method for producing a DNA chip (DNA microarray) in which several thousand to not less than ten thousand different types of DNA fragments are aligned and fixed as minute spots at a high density on a base plate such as a glass microscope slide.
2. Description of the Related Art
Methods for analyzing genetic structure have been remarkably progressed in recent years. A large number of genetic structures represented by those of human genes have been clarified. The analysis of genetic structures as described above uses a DNA chip (DNA microarray) in which several thousand to not less than ten thousand different types of DNA fragments are aligned and fixed as minute spots on a base plate such as a glass microscope slide.
In general, the DNA chip is produced by arranging a plurality of minute spots of a sample solution containing DNA fragments on a base plate such as glass. Those widely used as a method for forming the minute spots are based on a system such as the QUILL system, the pin & ring system, and the solid pin system in which a sample solution containing DNA fragments is supplied (stamped) onto the base plate by using a so-called pin. Even when any one of the foregoing methods is adopted, it is necessary to suppress the dispersion of the volume and the shape of each of the minute spots to be low so that the distance between the respective minute spots is maintained to be constant.
The PCR amplification step is used to prepare the sample solution containing the DNA fragments. The sample solution is often used while performing the amplification up to an amount of liquid required for the spot starting from a slight amount of original DNA. The amount of liquid obtained by the amplification is about several tens of microliters, and the reagents required for the amplification are expensive. Therefore, it is desirable to conserve reagents, which yields a more efficient use of the obtained liquid.
On the other hand, it is also desirable to realize a higher spot density. In this regard, it is necessary to develop a new method in which the shape control performance is satisfactory for the minute spot, and excellent productivity is realized as well.
When the minute spots are formed on the base plate by supplying the sample solution, the sample solution is prepared by PCR-amplifying a DNA fragment in a preparation vessel such as a cartridge beforehand to prepare a PCR product, drying the obtained PCR product to give DNA powder, and dissolving the obtained DNA powder in a buffer solution.
The sample solution is charged in a supply apparatus. The sample solution is supplied onto the base plate by using the supply apparatus to form the minute spots on the base plate.
In this procedure, the step of preparing the sample solution and the step of supplying the sample solution are separate from each other. Therefore, it is necessary to additionally perform management between the steps, and it is required to provide an equipment for preserving the sample solution. Further, the sample solution more probably contacts with the atmospheric air, and hence it is feared that the quality of the sample solution is deteriorated.
Further, the following problem arises because the sample solution is prepared in the preparation vessel such as the cartridge. That is, when the sample solution after the preparation is transferred to a pipette, a part of the sample solution remains in the cartridge. Further, when the sample solution is supplied to the supply apparatus by the aid of a pipette, a part of the sample solution also remains in the pipette. This procedure is also disadvantageous in the efficiency of utilization of the sample solution.
SUMMARY OF THE INVENTION
The present invention has been made taking the foregoing problems into consideration, an object of which is to provide a method for producing a DNA chip, which makes it possible to perform a series of steps of the preparation of a sample solution to the supply process without deteriorating the quality of the sample solution, improve the efficiency of utilization of the sample solution, realize the simplification of the preservation equipment for the sample solution, realize inexpensive cost, and improve the quality of the DNA chip.
According to the present invention, there is provided a method for producing a DNA chip by supplying a large number of sample solutions onto a base plate, comprising the steps of PCR-amplifying a DNA fragment to prepare a PCR product; drying the PCR product to prepare DNA powder; supplying the DNA powder into a solution supply apparatus; and supplying a buffer solution into the supply apparatus to prepare a sample solution; wherein the sample solution in the supply apparatus is supplied onto the base plate by using the supply apparatus to produce the DNA chip.
That is, in the present invention, the process for mixing the DNA powder and the buffer solution to prepare the sample solution, and the step of supplying the sample solution onto the base plate are performed in the identical supply apparatus. By doing so, the sample solution in the preparation vessel is moved in a powder state into the supply apparatus. Accordingly, it is possible to reduce any sample residue adhered, for example, to the vessel wall in the preparation vessel. Further, for example, it is unnecessary to use any pipette to move or transfer the sample. Thus, it is possible to avoid the occurrence of any residue of the sample remained and discarded in the pipette.
According to another aspect of the present invention, there is provided a method for producing a DNA chip, comprising the steps of PCR-amplifying a DNA fragment to prepare a PCR product; supplying the prepared PCR product into a solution supply apparatus; drying the PCR product in the supply apparatus to prepare DNA powder; and supplying a buffer solution into the supply apparatus to prepare a sample solution; wherein the sample solution in the supply apparatus is supplied onto the base plate by using the supply apparatus to produce the DNA chip.
That is, in the present invention, the process for drying the PCR product to prepare the DNA powder, and the process for mixing the DNA powder and the buffer solution to prepare the sample solution are performed in the identical supply apparatus.
Accordingly, it is possible to reduce the loss which would be otherwise caused, for example, by any scattering of the sample in the drying step. Thus, it is possible to improve the efficiency of utilization of the sample solution. Further, the series of operations, i.e., from the preparation of the DNA powder to the supply process, are performed in one supply apparatus. Therefore, the sample solution scarcely contacts with the atmospheric air. Thus, it is possible to avoid any deterioration of the quality of the sample solution.
According to still another aspect of the present invention, there is provided a method for producing a DNA chip, comprising the steps of PCR-amplifying a DNA fragment to prepare a PCR product in a solution supply apparatus; drying the PCR product in the supply apparatus to prepare DNA powder; and supplying a buffer solution into the supply apparatus to prepare a sample solution; wherein the sample solution in the supply apparatus is supplied onto the base plate by using the supply apparatus to produce the DNA chip.
That is, in the present invention, the series of steps ranging from the PCR amplification to the supply process are performed in the identical supply apparatus. Accordingly, the steps from the preparation of the sample solution to the supply process can be performed in accordance with the series of steps without deteriorating the quality of the sample solution. Further, it is possible to realize the simplification of the preservation equipment for the sample solution. It is possible to reduce the cost and improve the quality of the DNA chip.
It is unnecessary to perform any step of transferring the sample solution to another vessel. Therefore, it is possible to further improve the eff
Hirota Toshikazu
Noritake Motoo
Burr & Brown
Horlick Kenneth R.
NGK Insulators Ltd.
Strzelecka Teresa
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