Liquid purification or separation – Magnetic
Reexamination Certificate
2002-01-11
2004-04-20
Reifsnyder, David A. (Department: 1723)
Liquid purification or separation
Magnetic
C210S695000, C436S177000, C436S526000, C423S100000, C423S101000
Reexamination Certificate
active
06723237
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a concentration device using magnetic particles and a method therefor. More particularly, the present invention relates to a concentration device using magnetic particles and a concentration method using magnetic particles applied to medical treatment, examination, diagnosis, treatment, research, quantitative, qualitative, measurement or the like, in which concentration is automatically and reliably increased so that a target substance such as a microscopic amount of bacteria to be suspended in a large volume of liquid, is concentrated to thereby be suspended in a small volume of liquid, in order to perform processing such as separation, extraction or recovery of, for example, immunity substances such as antibodies or antigens, genetic substances (DNA, RNA, mRNA, oligonucleotide or the like), biopolymers such as proteins or hormone substances, organisms such as bacteria, viruses, cells, or other useful compounds such as medical drugs, in various fields such as the engineering field, medical field, agricultural field, scientific field and pharmaceutical science field.
BACKGROUND ART
Recently, the need for performing various processing such as separation, extraction, inspection or measurement of target substances such as organisms or biopolymers of bacteria or the like (for example, aqueous dissolved bacteria such as 0-157, cryptolipolysium, salmonella or the like, genetic materials such as DNA) is increasing.
For the purpose thereof, it is necessary to perform various processing after having cultured the bacteria, or in the case of genetic materials or the like, after having increased the concentration of the target substance by performing amplification.
The target substance such as bacteria or genetic materials is naturally obtained with a small amount thereof suspended in a large volume (for example, several liters) of liquid. In order to perform culture or amplification for this target substance, it is necessary to extract or separate the target substance from the suspension.
Therefore, separation and extraction has been heretofore performed by passing a large volume of suspension containing the target substance suspended therein through a filter. Normally, however, many impurities are contained other than the target substance in the suspension. In the case of a membrane filter or the like, these are likely to cause clogging due to the impurity and fouling. Hence this has the problem in that it is difficult or it requires time and labor to separate the target substance from a large volume of suspension.
Moreover, considering a case where a substance such as bacteria that affect organisms such as humans is handled, there is a demand for an apparatus which can automatically perform processing without requiring human intervention, which makes it possible to replace a part coming in contact with the suspension, and which does not require cleaning and can be used efficiently and reliably.
It is therefore a first object of the present invention to provide a concentration device using magnetic particles and a concentration method using magnetic particles, which can perform concentration of a large volume of liquid efficiently, quickly and reliably.
It is a second object of the present invention to provide a concentration device using magnetic particles and a concentration method using magnetic particles, wherein concentration, separation or extraction processing is not affected by the existence of impurities.
It is a third object of the present invention to provide a concentration device using magnetic particles and a concentration method using magnetic particles, wherein the part coming in contact with the suspension can have a construction such that a container or a disposable tip can be replaced, and a simple mechanism is used to thereby make it low-priced and easy to handle, without requiring cleaning.
It is a fourth object of the present invention to provide a concentration device using magnetic particles and a concentration method using magnetic particles, which are suitable for automated processing and consistent processing without requiring human intervention.
It is a fifth object of the present invention to provide a concentration device using magnetic particles and a concentration method using magnetic particles, suitable for handling microorganisms such as bacteria and biopolymers such as DNA substances. More particularly, it is an object of the present invention to provide a concentration device using magnetic particles and a concentration method using magnetic particles, suitable for amplification by a PCR method for genetic materials such as DNA.
DISCLOSURE OF THE INVENTION
In order to solve the above technical problems, a first aspect of the present invention is characterized by comprising: a liquid suction passage in which liquid can pass through only in a suction direction; a liquid discharge passage in which liquid can pass through only in a discharge direction; a magnetic force device which can exert a magnetic field from outside of the liquid passage on at least one liquid passage thereof or remove the magnetic field, and which can separate magnetic particles having directly or indirectly captured a target substance suspended in the liquid by having the magnetic particles adhere to the inner wall of the liquid passage; a storage section communicated with each liquid passage, for storing the sucked liquid; and a pressure adjustment device for sucking and discharging the liquid by adjusting the pressure in the storage section.
The term “directly capturing the target substance” herein stands for capturing the target substance by bonding the target substance such as bacteria with the magnetic particles. In order to do that, it is necessary that the magnetic particles have a substance for bonding with the target substance by means of a coating or the like. For example, there can be mentioned a case where glass is coated on the magnetic particles, and genetic materials such as DNA are adsorbed on the glass and captured.
The term “indirectly capturing the target substance” herein stands for a case where magnetic particles, target substance and a carrier originally existing separately and independently are suspended in liquid, and the carrier bonds with the magnetic particles and the target substance, so that magnetic particles capture the target substance. As the carrier, for example, there are gel substances such as hydroxyapatite and a cellulose carrier. When a gel substance such as hydroxyapatite is used as a carrier, the gel substance takes both the magnetic particles and the target substance into the inside thereof to thereby capture the target substance. When the cellulose carrier is used as a carrier, magnetic particles and the target substance are adhered to holes and gaps in the cellulose carrier to thereby capture the target substance. Capture can be effected by putting the magnetic particles or magnetic particles and the carrier into the liquid containing the target substance, and mixing or stirring these. The target substance captured by the magnetic particles can be dissolved by physical processing such as stirring or heating, or can be eluted or alienated from the magnetic particles by chemical processing such as by adjusting the pH to dissolve the target substance as with the hydroxyapatite, or by mixing with a reagent. The liquid suction passage and the liquid discharge passage are capable of passing the liquid only in the suction direction or in the discharge direction of the liquid by, for example, a check valve. The check valve may be provided in a part of the liquid suction passage and the liquid discharge passage, or may be provided outside the liquid suction passage and the liquid discharge passage, for example, attached to the storage section. When the suction port and the discharge port of the liquid passage are inserted into different containers, the suspension before separating the magnetic particles and the residual liquid after the separation thereof can be separated, thereby enabling efficie
Haynes and Boone LLP
Precision Systems Science Co., Ltd.
Reifsnyder David A.
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