1. Field of the Invention
The present invention relates to a nucleic acid purification instrument for purifying nucleic acids from a sample containing nucleic acids.
2. Background Art
Analysis of nucleic acids, which are substances that carry genetic information, is being carried out in a wide variety of fields, such as academic research and medicine. Nucleic acid analysis methods often involve nucleic acid amplification techniques, typically polymerase chain reaction (PCR).
Herein, “PCR” refers to a method for amplifying nucleic acids in a nucleotide-sequence-specific manner, whereby a gene of interest can be detected or quantified in minute amounts. Upon nucleic acid analysis involving PCR or the like, nucleic acids isolated from a biological sample or the like are used. Upon nucleic acid purification, it is necessary to remove the influence of contaminants, including inhibitors of an analysis reaction, such as nucleic acids derived from the external environment that cause false-positive analytical results.
In one conventional method for nucleic acid purification from a biological sample, an operation such as ethanol precipitation or the like is carried out using poisonous material such as phenol or chloroform. In recent years, it has been common to use a method utilizing a property of nucleic acids whereby nucleic acids adsorb to a silica-containing solid phase or the like in the presence of a chaotropic agent as described in J. Clin. Microbiol., 28(3), 495-503 (1990) or a method utilizing a property of nucleic acids whereby nucleic acids adsorb to organic macromolecules such as acetylcellulose in the presence of a chaotropic agent and an aqueous organic solvent as described in JP Patent Publication (Kokai) No. 2005-204578 A.
The method described in JP Patent Publication (Kokai) No. 2005-204578 A is a method wherein a solution containing nucleic acids is introduced into a purification cartridge comprising, as nucleic-acid-adsorptive members, organic macromolecules such as acetylcellulose and the solution is discharged through the nucleic-acid-adsorptive members by pressurization, such that nucleic acids are allowed to adsorb to the nucleic-acid-adsorptive members. In such case, a pressure change in a nucleic acid purification column immediately after the discharge of the entire volume of a solution is analyzed, a pressure release valve is operated, and then the pressurized air in the nucleic acid purification column is released. Accordingly, dispersion of the discharged solution in a mist form caused by the remaining pressurized air is prevented such that the risk of causing contamination is reduced.
In addition, in the case of JP Patent Publication (Kokai) No. 2006-197851 A, a solution is discharged from a nucleic acid capturing column into a partitioned space such that the contamination caused by solutions discharged from a plurality of provided nucleic acid capturing columns is prevented.