Probe carrier, probe fixing carrier and method of manufacturing the same

Abstract

A carrier having indexes in a probe non-fixing region is used and solutions containing probes are applied to respective specific positions on the carrier by referring to said indexes and fixed. The position of a target compound that is specifically bonded to a probe fixed to a probe carrier manufactured by a method according to the invention can be accurately and quickly detected by referring to the indexes.

Description

BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] This invention relates to a method of manufacturing a probe carrier by applying a probe solution to a specific position on a carrier, utilizing one or more than one indexes and an ink-jet method in particular. It also relates to a probe carrier manufactured by such a manufacturing method and a method of identifying the position of the target substance bonded to the probe on such a probe carrier by utilizing such indexes. [0003] 2. Related Background Art [0004] When analyzing the base sequence of a gene DNA or conducting a gene diagnosis for a number of items simultaneously, probes of different types are needed to single out a DNA having a target base sequence in order to raise the reliability of operation. DNA microchips have been attracting attention as means for providing probes of a number of different types to be used for such sorting operations. A large number of solution specimens (e.g., 96, 384 or 1,536 speci...

AI Technical Summary

Benefits of technology

[0020] In view of the above identified recent technological problems, it is therefore an object of the present invention to provide a probe fixing carrier that allows the operation of aligning the ejection head and the carrier to be conducted accurately and quickly when ejecting probe solutions onto the probe fixing carrier by means of an ink-jet system and also the operation of locating a target substance accurately and quickly when detecting and quantifying the latter.

[0021] Another object of the present invention is to provide a probe carrier that can effectively prevent the probe solutions being applied to respective probe fixing regions that are located adjacently and enclosed by a division wall from being mixed with each other and allows the probe solutions to sufficiently spread in the respective regions so as to prevent blank areas from being produced therein so that reliable probe carriers may be manufactured at a high yield.

Problems solved by technology

One of the problems to be solved for probe arrays formed by a group of a plurality of probe species is how to mount as many probes of different species, DNA probes having different base sequences for example, as possible on a single carrier.

Differently stated, it is a problem of how to mount probes in array as densely as possible.

Then, the cost and the time required for preparing such a probe array rise as the DNA chain length increases.

Furthermore, since the efficiency of nucleotide synthesis is not 100%, the ratio of DNAs that are defective in terms of the designed base sequence is not negligible.

Additionally, when photodecomposable protective groups are used for the synthesis process, the efficiency of synthesis is rather poor if compared with the use of ordinary acid-decomposable protective groups.

Besides, with the above identified known technique, since the products formed synthetically and directly on a carrier have to be used without any modification, it is not possible to sort out the DNAs having a defective base sequence from the DNAs having the designed respective base sequences and eliminate the former for the purpose of refining.

There is also a problem that it is not possible to confirm the base sequences of the DNAs synthetically formed on the carrier and ultimately obtained as an array.

This means that, if a base has not been subjected to predetermined elongation in a given elongation step probably because of an error or another in the step and hence the obtained probe array is not good, any screening operation using such a defective probe array gives rise to false results but there is no way of preventing such a problem from taking place.

In short, absence of confirmation of base sequences is the largest and most intrinsic problem of the above identified known technique.

While no problem may arise when each probe is applied with a dedicated capillary-shaped dispensing device, a mutual contamination problem will occur if a small number of capillary-shaped dispensing devices are used repeatedly for the operation, so that the capillary-shaped dispensing devices have to be cleaned sufficiently each time a new probe species is brought in to avoid such a mutual contamination problem.

Therefore, this technique is not suited for preparing a probe array comprising a wide variety of probes that are arranged densely.

Still additionally, the operation of applying a probe solution to the carrier is conducted by tapping the capillary tip to the carrier and hence not satisfactory in terms of both reproducibility and reliability.

However, this technique is basically an application of a stepwise elongation reaction on a carrier and hence is not free from certain problems including that of being unable to confirm the base sequences of the DNAs synthetically formed on the carrier as pointed out earlier to be the largest problem or the technique according to U.S. Pat. No. 5,424,186.

While the problem of conducting a cumbersome photolithography operation, using a dedicated mask in each elongation step, is dissolved with this technique, this technique is still accompanied to a certain extent by problems in terms of fixing predefined probes at respective positions, which is the requirement to be indispensably met for forming a probe array.

The use of a small number of such nozzles is not suited for preparing high density probe arrays like the above described method of using capillary-shaped dispensing devices.

However, with known probe fixing methods that utilize a conventional ink-jet process, it is often impossible to apply liquid accurately to a desired position as the liquid ejecting operation is conducted by regulating the relative positions of the carrier and the ink-jet head, visually confirming the posture of the entire carrier.

However, if the probe solution applied to the carrier by the last liquid-ejecting operation dries, it will no longer be possible to visually ascertain that the probe solution has been applied to the right position on the carrier.

Therefore, the next liquid-ejecting operation has to be conducted before the probe solution applied to the carrier in the last liquid-ejecting operation dries and after visually confirming that the probe solution has been applied to the right position to make the manufacture of such a probe carrier disadvantageous.

Furthermore, this technique is accompanied by additional problems including that the operation of visually aligning the carrier and the ink-jet head is time consuming and the number of points to be used for observing the alignment of the carrier and the ink-jet head is limited to make the alignment inaccurate.

Moreover, if the probe carrier is turned upside down relative to the ink-jet head during the operation of manufacturing the probe carrier, it cannot be checked, if the carrier is transparent, simply by observing the carrier.

However, as a result of intensive research efforts, the inventors of the present invention found that, unless the ink-jet head is not accurately aligned relative to the probe carrier, the probe solutions of adjacently located apertures (wells) with a division wall interposed therebetween can become mixed with each other (to produce a mixed solution) so that it may no longer be possible to apply the proper probes to the intended position on the probe carrier.

Then, the probe carrier will not function properly.

Additionally, if the positions of ejection points are displaced, the probe solution in each well can be spread unevenly to expose the surface of the probe carrier over a large area.

Then, there arise problems such as unreliable detection, difficulty of quantification, appearance of bright blank areas (also referred to simply as “blank areas”) and an increase of unspecified bonds.

Then, probes will not be formed uniformly on the probe carrier as a result of applying probe solutions to the latter.

While the phenomenon of appearance of blank areas may be reduced when probe solutions are applied at an enhanced rate, it will not be totally eliminated.

Furthermore, it is a problem to be solved urgently that the time required for aligning the ink-jet head and the probe carrier needs to be reduced because the operation of adjusting their relative positions and the use of a detector for detecting the overall profile of the black matrix for the purpose of alignment are time consuming and hence raise the manufacturing cost per chip.

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