ANALYSIS METHOD AND ANALYSIS DEVICE
20220291210 · 2022-09-15
Inventors
Cpc classification
G01N2333/94
PHYSICS
G01N33/543
PHYSICS
C12Y302/01023
CHEMISTRY; METALLURGY
H01J49/4225
ELECTRICITY
International classification
G01N33/543
PHYSICS
Abstract
Provided is a high-accuracy analysis method utilizing an enzyme-lined immunoassay. The presence of an analyte 3 can be detected or the abundance of the analyte 3 can be analyzed by: bonding an antibody 5 that is capable of specifically bonding to the analyte 3 immobilized on a solid phase 1 and has an enzyme 7 bonded thereto; then decomposing an enzyme substrate 8, which can generate decomposition products capable of being detected easily with a mass spectrometry, with the enzyme 7 bonded to the antibody 5; and then analyzing the decomposition products 9 and 10 with a mass spectrometry.
Claims
1. An analysis method for measuring an analyte, wherein an analyte is immobilized on a solid phase, wherein an antibody to which a label to be specifically bonded to the analyte immobilized on the solid phase is bonded to the analyte, wherein a label bonded substance having galactosidase bonded thereto is bonded to the label, wherein enzyme reaction is caused to occur between the galactosidase bonded to the label bonded substance and an enzyme substrate, and wherein mass spectrometry is performed on an enzyme reaction product of the obtained enzyme substrate so as to measure the presence or absence and concentration of the analyte.
2. The analysis method according to claim 1, wherein as the label and the label bonded substance, biotin and avidin are used.
3. The analysis method according to claim 1, comprising: a step of immobilizing the analyte on the solid phase; a step of bonding the antibody to be specifically bonded to the analyte and having the galactosidase bonded thereto to the analyte; an enzyme reaction step of adding the enzyme substrate and causing the enzyme substrate to react with the galactosidase for a prescribed time; and an analysis step of causing a mass spectrometer to analyze the obtained enzyme reaction product.
4. The analysis method according to claim 1, wherein the enzyme reaction product serving as an analysis target is a compound in which log P serving as a hydrophobicity index is 1 to 5 and a molecular weight is 150 to 1,000.
5. The analysis method according to claim 4, wherein the enzyme reaction product has a structure in which a plurality of aromatic compounds are linked by a linker including single bonding of C—N or C—O, and is a compound having the molecular weight of 200 to 600.
Description
BRIEF DESCRIPTION OF DRAWINGS
[0014]
[0015]
[0016]
[0017]
DESCRIPTION OF EMBODIMENTS
[0018] Hereinafter, preferred embodiments of an analysis method and an analysis device which utilize a new method in an enzyme-lined immunoassay according to the present invention will be described. First, a principle of the analysis method according to the present invention will be described with reference to an example of the enzyme-lined immunoassay illustrated in
[0019] As illustrated in
[0020] Furthermore, if an enzyme substrate 8 to react with the enzyme 7 is added, the enzyme substrate 8 generates enzyme reaction products 9 and 10 through enzyme reaction. As an example, the label 4 and the label bonded substance 6 include a combination of biotin and avidin or streptavidin. However, the label bonded substance 6 may be an anti-labeled antibody by setting the label 4 to any optional compound. Without using the label 4, an anti-anti-analyte antibody for recognizing the anti-analyte antibody 5 or antibody bonding protein such as protein G or A may be used.
[0021] A specific example of the enzyme reaction caused by the enzyme substrate is as follows. In the reaction of β-galactosidase, p-nitrophenyl β-D-galactoside is decomposed, and p-nitrophenol is liberated. This p-nitrophenol is colored in weak alkaline, thereby enabling this p-nitrophenol to be measured by being absorbed as much as 420 nm.
[0022] In peroxidase, hydrogen peroxide is decomposed, 3,3′, 5,5′-tetramethylbenzidine is oxidized by active oxygen generated in response thereto, is colored in acid, and is measured by being absorbed as much as 450 nm. Alkaline phosphatase decomposes p-nitrophenyl phosphate, and p-nitrophenol is formed, thereby measuring the absorbance at 405 nm. Acetylcholinesterase decomposes acetylcholine into acetic acid and thiocholine. This thiocholine cleaves disulfide bonding of 5,5′-dithio-bis-(2-nitrobenzoic acid), and 5-thio-2-nitrobenzoic acid is formed, thereby measuring the absorbance at 412 nm.
[0023] In addition to this configuration, as a substrate of β-galactosidase, phenyl β-D-galactoside, p-aminophenyl β-D-galactoside, p-methoxyphenyl β-D-galactoside, o-nitrophenyl β-D-galactoside, p-methylumbelliferyl-β-galactoside, p-5-bromo-4-chloro-3-indolyl β-D-galactopyranoside, 5-bromo-6-chloro-3-indolyl β-D-galactopyranoside, 5-bromo-3-indolyl β-D-galactopyranoside, 6-chloro-3-indolyl β-D-galactopyranoside, and o-nitrophenyl β-D-galactopyranoside are known.
[0024] As a substrate of peroxidase, 4-aminoantipyrine, 2,2′-azinobis (3-ethylbenzothiazoline-6-ammonium sulfonate), 5-aminosalicylic acid, 3,5-dichloro-2-hydroxybenzenesulfonic acid, 2,4-dichlorophenol, N,N-dimethylaniline, 3-diethylaminotoluene, 3-methyl-2-benzothiazolinone hydrazone, 2,2′-azinodi (3-ethylbenzthiazolidine)-6′-sulfonate, 1,2-phenylenediamine, 3-(3,5-dimethoxyanilino)-2-hydroxypropanesulfonic acid, 2,4,6-tribromo-3-hydroxybenzoic acid, tyramine, and p-hydroxyphenylpropionic acid are known. As a substrate of alkaline phosphatase, 4-methylumbelliferyl phosphate is known.
[0025] However, the enzyme-lined immunoassay in the related art utilizes colorimetry or fluorescence as described above. The enzyme-lined immunoassay is likely to receive the influence of turbidity or bubbles of a sample solution, and in addition, a material of a usable container is restricted.
[0026] Therefore, in the analysis method and the analysis device which utilize the enzyme-lined immunoassay according to the present invention, as the enzyme substrate reacting with the enzyme, a compound whose enzyme reaction product is likely to be detected through mass spectrometry using the mass spectrometer (MS). Although MS has various types, it is more preferable to use an electrospray ionization-triple quadrupole MS. The electrospray ionization is a method in which a substance in a solution is stably ionized by a potential difference and spray gas. Three electrodes of the quadrupole MS are arranged in series, and ion of any optional m/z is selected by the first quadrupole. The ion is decomposed by the subsequent quadrupole, and any optional decomposed ion is detected by the last quadrupole. Due to a difference in m/z, most other substances are separated by the first quadrupole. A decomposition pattern is characterized by a compound in the subsequent quadrupole. Accordingly, even in a case of the compound accidentally mixed with the same m/z in the first quadrupole, a deposition product varies. It is possible to very selectively measure the amount of a specific substance in the last quadrupole.
[0027] The compound which is likely to be detected by MS having this configuration is likely to be ionized by the electrospray, and is likely to be quantified by the triple quadrupole. The enzyme reaction product 9 which serves as a major analyte illustrated in
[0028] A second characteristic to facilitate analysis using MS is that interference between compounds does not occur. In some cases, interference occurs in the presence of an isotope element or in the mass spectrometry using an adduct ion, a dehydration ion, or the like even though masses of compounds are different. In order to eliminate this case, it is desirable that difference between m/z values is by 40 or more. In addition, if compounds are simultaneously ionized even though the compounds have different masses, there is a high possibility of causing interference called ion suppression. In the enzyme reaction, a reaction rate is increased by increasing the concentration of a reaction substrate, and thus, it is expected that the concentration of the reaction substrate becomes higher than that of a detected compound and the ionization of the detected compound is inhibited.
[0029] In the enzyme reaction system of the analysis method using the enzyme-lined immunoassay according to the present invention, the enzyme is immobilized into the solid phase, and thus, the enzyme substrate and salts or organic solvents such as a reaction product or a buffer solution are present. In order to easily separate the detected compound from the enzyme substrate through chromatography, it is desired that chemical properties are significantly different. For example, in a case where β-galactosidase which is one of glycolytic enzymes is used as the enzyme and p-nitrophenyl-β-galactoside is used as the enzyme substrate, the reaction product is p-nitrophenol used in detection and galactose recognized by the enzyme. These components are easily separated through hydrophobic chromatography such as C18 having significantly different polarities. In addition, examples of impurities in MS include water or an organic solvent such as water or acetonitrile, used as a mobile phase, and a buffer solution component such as ammonia or formic acid or a cluster formed by gathering several molecules thereof, in addition to compounds derived from the sample. To avoid generation of the impurities, it is desired that m/z is 150 or greater. However, if the mass is increased, it cannot be interpreted that polyvalent ions are easily generated, and thus, it is preferable that the molecular weight of the compound is 1,000 or less.
[0030] In view of the above-described configuration, in the analysis method using the enzyme-lined immunoassay according to the present invention, it is desired that an enzyme reaction product which is a MS analysis object generated by the enzyme reaction has log P, which is an index of hydrophobicity, of 1 to 5, and is a compound having a molecular weight of 150 to 1,000. Furthermore, in the triple quadrupole MS, compound is decomposed in a second triple quadrupole, and analysis accuracy is improved using the fact decomposition patterns thereof are different for each compound. In some cases, it is less likely to be interpreted that decomposition does not easily occur in a small molecule and decomposition is too complicated in a large molecule. Stable decomposition easily occurs in a structure in which a plurality of aromatic compounds are connected via a linker including a single bond of C—N or C—O. In the light of this, in the analysis method and the analysis device according to the present invention, it is desired that the enzyme reaction product which is a MS analysis object has a structure in which a plurality of aromatic compounds are connected via a linker including a single bond of C—N or C—O, and is a compound having a molecular weight of 200 to 600. As an example of the enzyme reaction product, verapamil (C27H.sub.38O.sub.4, molecular weight of 454.61) is used.
Embodiment 1
[0031] Subsequently, a first embodiment of the analysis method and the analysis device according to the present invention will be described with reference to
[0032] The present embodiment is an embodiment of an analysis method in which an antibody to be specifically bonded to an analyte immobilized on a solid phase and having an enzyme bonded thereto is bonded to the analyte, enzyme reaction is caused to occur between the enzyme bonded to the antibody and an enzyme substrate, and mass spectrometry is performed on an enzyme reaction product of the obtained enzyme substrate so as to detect the presence or absence of the analyte and to measure concentration of the analyte. In addition, the present embodiment is an embodiment of the analysis device which includes an enzyme reaction unit that bonds an antibody to be specifically bonded to an analyte immobilized on a solid phase and having an enzyme bonded thereto to the analyte so as to cause enzyme reaction to occur between the enzyme bonded to the antibody and an enzyme substrate, and a mass spectrometry unit that performs mass spectrometry on an enzyme reaction product of the obtained enzyme substrate, and detects the presence or absence of the analyte and measures concentration of the analyte.
[0033] The automatic analysis device according to Embodiment 1 shown in
[0034] As illustrated in
[0035] The reaction container 31 on the reaction table 30 containing the specimen is transferred to an operation part of a suction nozzle 32 after a prescribed time (S2), and a supernatant after reaction is sucked and removed (S3). The suction nozzle 32 is cleaned using the nozzle cleaning mechanism 33. Next, the reaction container 31 is transferred to an operation part of a cleaning solution supply nozzle 34, and a cleaning solution is charged (S4). The cleaning solution supply nozzle 34 is cleaned using a nozzle cleaning mechanism 35. The reaction container 31 is cleaned several times by reciprocating between the suction nozzle operation part and the cleaning solution supply nozzle operation part (S4 and S5).
[0036] The cleaned reaction container 31 is transferred to an operation part of a reagent supply nozzle 50, and filled with a complex of a label 4 and the anti-analyte antibody 5 from a reagent container 51 (S6). The reagent supply nozzle 50 is cleaned using a nozzle cleaning mechanism 52. A reagent table 53 has a plurality of reagent containers 51 stored therein, and has an appropriate constant temperature function or stirring function. The reaction container 31 is transferred to the operation part of a suction nozzle 32 after a certain time (S7), and a supernatant after reaction is sucked and removed (S8). The reaction container 31 is cleaned several times by reciprocating between the suction nozzle operation part and the cleaning solution supply nozzle operation part (S9 and S10).
[0037] Next, the reaction container 31 is transferred to the operation part of a reagent supply nozzle 50, and is filled with a complex of a label bonded substance 6 and an enzyme 7 (S11). The reaction container 31 is transferred to the operation part of a suction nozzle 32 after a certain time (S12), and a supernatant after reaction is sucked and removed (S13). The reaction container 31 is cleaned several times by reciprocating between the suction nozzle operation part and the cleaning solution supply nozzle operation part (S14 and S15).
[0038] Then, the reaction container 31 is transferred to the operation part of a reagent supply nozzle 50, and is filled with an enzyme substrate 8 (S16). The reaction container 31 is transferred to an operation part of a sample injection nozzle mechanism 60 after a certain time (S17), a certain amount of a specimen passes through an LC/MS sample injection unit 70, and analysis is performed in LC/MS 71 which is a mass spectrometry unit (S18). The sample injection nozzle mechanism 60 is cleaned using a cleaning mechanism 61. In a case where analysis cannot be immediately performed after the lapse of a certain time from filling with enzyme substrate 8, the reaction container 31 is filled with an enzyme reaction stop solution by the reagent supply nozzle 50, temporarily held in an analysis sample container 63 on an analysis sample table by the sample injection nozzle mechanism 60, and sequentially analyzed in LC/MS 71 configuring a mass spectrometry unit. The reaction container 31 into which the sample is completed injected is transferred to a completed reaction container accommodation unit 42 by the reaction container transfer unit 40.
[0039] According to the automatic analysis device and the analysis method of Embodiment 1 described above, it is possible to very sensitively analyze an analysis target by the enzyme-lined immunoassay, and easily perform analysis of versatile substances such as protein using MS.
Embodiment 2
[0040] As described above, various methods are used for the enzyme-lined immunoassay, and as Embodiment 2, unlike the analysis method of Embodiment 1, an embodiment of using an anti-anti-analyte antibody for recognizing an anti-analyte antibody without using a label will be described.
[0041] As illustrated in the same drawing, the reaction container 31 subjecting to cleaning several times (S4 and S5) is transferred to the operation part of the reagent supply nozzle 50, and in the present embodiment, the reaction container 31 is filled with a complex of the anti-analyte antibody 5 and the enzyme 7 (S19). Next, similar to Embodiment 1, the reaction container 31 is transferred to the operation part of the suction nozzle 32 after a certain time (S12), and a supernatant after reaction is sucked and removed (S13). The reaction container 31 is cleaned several times by reciprocating between the suction nozzle operation part and the cleaning solution supply nozzle operation part (S14 and S15). Then, the reaction container 31 is transferred to the operation part of the reagent supply nozzle 50 and is filled with the enzyme substrate 8, and the enzyme reaction is performed (S16). The reaction container 31 is transferred to the operation part of the sample injection nozzle mechanism 60 after a certain time (S17), a certain amount of a specimen passes through the LC/MS sample injection unit 70, and analysis is performed in LC/MS 71 which is a mass spectrometry unit (S18).
[0042] According to the present embodiment, the label is not used, and thus, it is possible to simplify analysis procedures. In addition, similar to Embodiment 1, it is possible to very sensitively analyze an analysis target by the enzyme-lined immunoassay, and easily perform analysis of versatile substances such as protein using MS.
[0043] Subsequently, analysis examples in which analysis is performed by applying various embodiments described above will be sequentially described.
Analysis Example 1
[0044] Prior to Analysis Examples 2 to 5, as Analysis Example 1, galactosidase which is the enzyme 7 was caused to react respectively with p-nitrophenyl-β-galactoside, 4-methylumbelliferyl-β-galactoside, and a verapamil derivative of β-galactoside, as the enzyme substrate 8, and reaction products were analyzed respectively by LC/MS which is a the mass spectrometry unit and the spectrometric analysis device. 4-Nitrophenol (C.sub.6H.sub.5NO.sub.3, molecular weight of 139.11) which is one of the enzyme reaction products can be obtained with detection sensitivity similar to spectra in LC/MS. 4-Methylumbelliferone (C.sub.10H.sub.8O.sub.3, molecular weight of 176.171) which is one of the reaction products can be detected with higher sensitivity than spectra in LC/MS. Furthermore, verapamil (C27H.sub.38O.sub.4, molecular weight of 454.61) which is one of the reaction products can be detected with extremely high sensitivity in LC/MS.
Analysis Example 2
[0045] The present analysis example is an analysis example related to Embodiment 1 described with reference to
Analysis Example 3
[0046] The present analysis example is an analysis example related to Embodiment 1 described with reference to
Analysis Example 4
[0047] The present analysis example is an analysis example related to Embodiment 1 described with reference to
Analysis Example 5
[0048] The present analysis example is an analysis example related to Embodiment 2 described with reference to
[0049] According to the analysis method and the analysis device of the present invention which are described above, clinical test items are widely expanded and accuracy in analyzing the clinical test items is improved by very sensitively analyzing biological components.
[0050] Furthermore, the present invention is not limited to the embodiments described above, and includes various modification examples. For example, the embodiments described above have been described in detail for facilitating better understanding of the present invention. A configuration of a certain embodiment can be partially substituted with a configuration of the other embodiment. In addition, a configuration of the other embodiments can be added to the configuration of the certain embodiment. In addition, with regard to a part of a configuration of each embodiment, additions, omissions, and substitutions of other configurations can be made.
REFERENCE SIGNS LIST
[0051] 1: SOLID PHASE, [0052] 2: ANTI-ANALYTE ANTIBODY, [0053] 3: ANALYTE, [0054] 4: LABEL, [0055] 5: ANTI-ANALYTE ANTIBODY, [0056] 6: LABEL BONDED SUBSTANCE, [0057] 7: ENZYME, [0058] 8: ENZYME SUBSTRATE, [0059] 9: ENZYME REACTION PRODUCT WHICH SERVES AS MAJOR ANALYSIS TARGET, [0060] 10: ENZYME REACTION PRODUCT WHICH DOES NOT SERVE AS MAJOR ANALYSIS TARGET, [0061] 20: SPECIMEN SUPPLY UNIT, [0062] 21: SPECIMEN CONTAINER, [0063] 22: SPECIMEN DISPENSING DEVICE, [0064] 23: NOZZLE CLEANING MECHANISM, [0065] 30: REACTION TABLE, [0066] 31: REACTION CONTAINER, [0067] 32: SUCTION NOZZLE, [0068] 33: NOZZLE CLEANING MECHANISM, [0069] 34: CLEANING SOLUTION SUPPLY NOZZLE, [0070] 35: NOZZLE CLEANING MECHANISM, [0071] 40: REACTION CONTAINER TRANSFER UNIT, [0072] 41: REACTION CONTAINER STOCKER, [0073] 42: COMPLETED REACTION CONTAINER ACCOMMODATION UNIT, [0074] 50: REAGENT SUPPLY NOZZLE, [0075] 51: REAGENT CONTAINER, [0076] 52: NOZZLE CLEANING MECHANISM, [0077] 53: REAGENT TABLE, [0078] 60: SAMPLE INJECTION NOZZLE MECHANISM, [0079] 61: NOZZLE CLEANING MECHANISM, [0080] 62: ANALYSIS SAMPLE TABLE, [0081] 63: ANALYSIS SAMPLE CONTAINER, [0082] 70: LC/MS SAMPLE INJECTION UNIT, [0083] 71: LC/MS