This disclosure relates generally to immunomagnetic separation and, in particular, to systems and methods for separation of a target analyte of a suspension from the other component materials of the suspension with a magnetic field or magnetic gradient.
Suspensions often include materials of interest that are difficult to detect, extract and isolate for analysis. For instance, whole blood is a suspension of materials in a fluid. The materials include billions of red and white blood cells and platelets in a proteinaceous fluid called plasma. Whole blood is routinely examined for the presence of abnormal organisms or cells, such as fetal cells, endothelial cells, epithelial cells, parasites, bacteria, and inflammatory cells, and viruses, including HIV, cytomegalovirus, hepatitis C virus, and Epstein-Barr virus and nucleic acids. Currently, practitioners, researchers, and those working with blood samples try to separate, isolate, and extract certain components of a peripheral blood sample for examination. Typical techniques used to analyze a blood sample include the steps of smearing a film of blood on a slide and staining the film in a way that enables certain components to be examined by bright field microscopy.
On the other hand, materials of interest composed of particles that occur in very low numbers are especially difficult if not impossible to detect and analyze using many existing techniques. Consider, for instance, circulating tumor cells (“CTCs”), which are cancer cells that have detached from a tumor, circulate in the bloodstream, and may be regarded as seeds for subsequent growth of additional tumors (i.e., metastasis) in different tissues. The ability to accurately detect and analyze CTCs is of particular interest to oncologists and cancer researchers, but CTCs occur in very low numbers in peripheral whole blood samples. For instance, a 7.5 ml sample of peripheral whole blood that contains as few as 3 CTCs is considered clinically relevant in the diagnosis and treatment of a cancer patient. However, detecting even 1 CTC in a 7.5 ml blood sample may be clinically relevant and is equivalent to detecting 1 CTC in a background of about 40-50 billion red and white blood cells. Using existing techniques to find, isolate and extract as few as 3 CTCs of a whole blood sample is extremely time consuming, costly and is extremely difficult to accomplish.
As a result, practitioners, researchers, and those working with suspensions continue to seek systems and methods to more efficiently and accurately detect, isolate and extract target materials of a suspension.
This disclosure is directed to systems and methods for immunomagnetic separation of a target analyte of a suspension from the other component materials of the suspension. The system may be composed of a tube, a float, and a magnet. The magnet introduces a magnetic field or a magnetic gradient to the system. The system may also include a solution containing a particle to conjugate with the target analyte to form a target analyte-particle complex. The particle is capable of being attracted by the magnetic field or magnetic gradient introduced by the magnet. The target analyte-particle complex may be attracted to the sidewall of the tube after the suspension undergoes density-based separation, such as by centrifugation.
Methods and systems for separating component materials of a suspension are disclosed. The detailed description is organized into two subsections: (1) A general description of various tube and float systems is provided in a first subsection. (2) Examples of methods and systems for separating component materials of suspensions using tube and float systems in which a magnetic field is introduced to attract and hold the target analyte to the tube are provided in a second subsection.
Embodiments include other types of geometric shapes for float end caps.
In other embodiments, the main body of the float 104 can include a variety of different support structures for separating target materials, supporting the tube wall, or directing the suspension fluid around the float during centrifugation.
The float can be composed of a variety of different materials including, but not limited to, metals, including, but not limited to, aluminum, brass, gold, silver, tin, copper, bronze, chromium, cobalt, nickel, lead, iron, steel, manganese, zinc, neodymium, and combinations thereof; rigid organic or inorganic materials; ferrous plastics; sintered metal; machined metal; and rigid plastic materials, such as polyoxymethylene (“Delrin®”), polystyrene, acrylonitrile butadiene styrene (“ABS”) copolymers, aromatic polycarbonates, aromatic polyesters, carboxymethylcellulose, ethyl cellulose, ethylene vinyl acetate copolymers, nylon, polyacetals, polyacetates, polyacrylonitrile and other nitrile resins, polyacrylonitrile-vinyl chloride copolymer, polyamides, aromatic polyamides (“aramids”), polyamide-imide, polyarylates, polyarylene oxides, polyarylene sulfides, polyarylsulfones, polybenzimidazole, polybutylene terephthalate, polycarbonates, polyester, polyester imides, polyether sulfones, polyetherimides, polyetherketones, polyetheretherketones, polyethylene terephthalate, polyimides, polymethacrylate, polyolefins (e.g., polyethylene, polypropylene), polyallomers, polyoxadiazole, polyparaxylene, polyphenylene oxides (PPO), modified PPOs, polystyrene, polysulfone, fluorine containing polymer such as polytetrafluoroethylene, polyurethane, polyvinyl acetate, polyvinyl alcohol, polyvinyl halides such as polyvinyl chloride, polyvinyl chloride-vinyl acetate copolymer, polyvinyl pyrrolidone, polyvinylidene chloride, specialty polymers, polystyrene, polycarbonate, polypropylene, acrylonitrite butadiene-styrene copolymer, butyl rubber, ethylene propylene diene monomer, others, and combinations thereof.
The tube can be composed of a variety of different materials. The tube can be composed of glass; a rigid organic or inorganic materials; and rigid plastic materials, such as polyoxymethylene (“Delrin®”), polystyrene, acrylonitrile butadiene styrene (“ABS”) copolymers, aromatic polycarbonates, aromatic polyesters, carboxymethylcellulose, ethyl cellulose, ethylene vinyl acetate copolymers, nylon, polyacetals, polyacetates, polyacrylonitrile and other nitrile resins, polyacrylonitrile-vinyl chloride copolymer, polyamides, aromatic polyamides (“aramids”), polyamide-imide, polyarylates, polyarylene oxides, polyarylene sulfides, polyarylsulfones, polybenzimidazole, polybutylene terephthalate, polycarbonates, polyester, polyester imides, polyether sulfones, polyetherimides, polyetherketones, polyetheretherketones, polyethylene terephthalate, polyimides, polymethacrylate, polyolefins (e.g., polyethylene, polypropylene), polyallomers, polyoxadiazole, polyparaxylene, polyphenylene oxides (PPO), modified PPOs, polystyrene, polysulfone, fluorine containing polymer such as polytetrafluoroethylene, polyurethane, polyvinyl acetate, polyvinyl alcohol, polyvinyl halides such as polyvinyl chloride, polyvinyl chloride-vinyl acetate copolymer, polyvinyl pyrrolidone, polyvinylidene chloride, specialty polymers, polystyrene, polycarbonate, polypropylene, acrylonitrite butadiene-styrene copolymer, butyl rubber, ethylene propylene diene monomer, others, and combinations thereof.
The tube may have a sidewall and a first diameter. The float can be captured within the tube by an interference fit. To remove the float from the tube after the float has been captured, the sidewall, being elastically radially expandable to a second diameter, may be expanded in response to an axial load, pressure due to centrifugation, external vacuum, or internally-introduced pressure, the second diameter being sufficiently large to permit axial movement of the float in the tube during centrifugation. Alternatively, the support members may not engage the inner wall of the tube. Alternatively, the float may not include any support members.
A doubly-conjugated ligand is a ligand which has been conjugated with two distinct molecules, such that the two molecules are not of the same composition or structure. The doubly-conjugated ligand provides a wide range of applications, such as a fluorescent linker between two articles, such that it is conjugated with a fluorescent marker and a distinct molecule so that the fluorescent marker emits a light signal upon excitation. The doubly-conjugated ligand provides a more functional way of linking two or more articles. The doubly-conjugated ligand may also amplify the detectable signal of the labeled article. To doubly conjugate the ligand, an unlabeled ligand may first be added to a reactive solution containing both a reactive first molecule and a reactive second molecule, such that the reactive first and second molecules are not of the same composition or structure. Next, the solution is incubated. The reactive second and third molecules compete for attachment to the unfilled conjugation sites of the ligand, thereby conjugating the ligand with some of the reactive second molecule and some of the reactive third molecule. In order to do this, however, a portion of the molar concentrations of each of the second and third molecules will be used, such that the total molar amount will be the same as when a single labeling reaction was done. Alternatively, the second and third molecules may be reactive with different conjugation chemistries.
Alternatively, to doubly conjugate a ligand, the ligand may be pre-labeled with the third molecule and then added to a solution comprising the reactive second molecule, such that the third molecule and the reactive second molecule are not of the same composition or structure. Next, the solution is incubated. The reactive second molecule will attach to at least one of the unfilled conjugation sites on the ligand pre-labeled with the third molecule.
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Alternatively, the particle may be bound to the first intermediary, such that the first intermediary is an anti-fluorophore antibody. The second intermediary includes one or more fluorophores, such that the first intermediary, being the anti-fluorophore antibody, binds to a fluorophore of the second intermediary. The second intermediary binds to the target analyte.
The particle may come in any form, including, but not limited to, a bead, a nanoparticle (such as a quantum dot), a shaving, a filing, or the like, such that the particle is capable of being attracted by a magnetic field or magnetic gradient introduced by a magnet. The particle may itself be magnetic, diamagnetic, ferromagnetic, paramagnetic, or superparamagnetic. The particle 1014 may be composed of a variety of different materials including, but not limited to, metals, including, but not limited to, aluminum, brass, gold, silver, tin, copper, bronze, chromium, cobalt, nickel, lead, iron, steel, manganese, zinc, neodymium, and combinations thereof at least one organic material, at least one inorganic material, at least one mineral, at least one ferrofluid, at least one plastic, at least one polymer and combinations thereof.
Returning to
In block 710, the tube and float system may be imaged.
The excitation light is focused by an objective 1104 onto the analysis area, which is a space between the float and tube in which a target analyte may be retained or trapped. The different wavelengths excite different fluorescent markers, causing the fluorescent markers to emit light at lower energy wavelengths. A portion of the light emitted by the fluorescent markers is captured by the objective 1104 and transmitted to a detector 1106 that generates images that are processed and analyzed by a computer or associated software or programs. The images formed from each of the channels can be overlaid when a plurality of fluorescent markers, having bound themselves to the target analyte, are excited and emit light. The light source 1102 and the objective 1104 may be separate pieces or may be one piece. The light source 1102 and the objective 1104 may be coaxial or may be located on different planes. The target analyte 804 can then be characterized, and its location identified, based on the light emission(s) from the fluorescent marker(s) 810 attached to the target analyte 804.
Returning to
The magnet includes, but is not limited to, a ring magnet, a bar magnet, a horseshoe magnet, an electromagnet, a switchable magnet, a spherical magnet, a polygon-shaped magnet, a polyhedral shape, a wand magnet, a kidney-shaped magnet, a trapezoidal magnet, a disk magnet, a cow magnet, or a block or brick magnet. When more than one magnet is used, the magnets may be different or the same in both size and shape.
Returning to
Referring now to
The target analyte may be analyzed using any appropriate analysis method or technique, though more specifically extracellular and intracellular analysis including intracellular protein labeling; nucleic acid analysis, including, but not limited to, DNA arrays, expression arrays, protein arrays, and DNA hybridization arrays; in situ hybridization (“ISH”—a tool for analyzing DNA and/or RNA, such as gene copy number changes); polymer chain reaction (“PCR”); reverse transcription PCR; or branched DNA (“bDNA”—a tool for analyzing DNA and/or RNA, such as mRNA expression levels) analysis. These techniques require fixation, permeabilization, and isolation of the target analyte prior to analysis. Some of the intracellular proteins which may be labeled include, but are not limited to, cytokeratin (“CK”), actin, Arp2/3, coronin, dystrophin, FtsZ, myosin, spectrin, tubulin, collagen, cathepsin D, ALDH, PBGD, Akt1, Akt2, c-myc, caspases, survivin, p27kip, FOXC2, BRAF, Phospho-Akt1 and 2, Phospho-Erk1/2, Erk1/2, P38 MAPK, Vimentin, ER, PgR, PI3K, pFAK, KRAS, ALKH1, Twist1, Snail1, ZEB1, Fibronectin, Slug, Ki-67, M30, MAGEA3, phosphorylated receptor kinases, modified histones, chromatin-associated proteins, and MAGE. To fix, permeabilize, or label, fixing agents (such as formaldehyde, formalin, methanol, acetone, paraformaldehyde, or glutaraldehyde), detergents (such as saponin, polyoxyethylene, digitonin, octyl β-glucoside, octyl β-thioglucoside, 1-S-octyl-β-D-thioglucopyranoside, polysorbate-20, CHAPS, CHAPSO, (1,1,3,3-Tetramethylbutyl)phenyl-polyethylene glycol or octylphenol ethylene oxide), or labeling agents (such as fluorescently-labeled antibodies, enzyme-conjugated antibodies, Pap stain, Giemsa stain, or hematoxylin and eosin stain) may be used.
In direct conjugation, the first molecule of the particle bonds directly with the CTC. In first-degree indirect conjugation, the particle having a first molecule is conjugated to the CTC via a doubly-conjugated ligand. The doubly-conjugated ligand is bound to a second molecule and a third molecule. The second molecule is a complementary molecular conjugate to that of the first molecule such that the first molecule and the second molecule bond to each other. In second-degree indirect conjugation, the CTC is conjugated to the particle via the first intermediary particle bound to a second molecule and the fluorescent marker-conjugated second intermediary particle while in the tube or prior to introduction into the tube.
The first molecule of the particle, whether introduced to the particle through binding, coating, or attaching, may include, but is not limited to, an avidin, such as streptavidin or neutravidin; Protein A, Protein G, Protein L; biotin; an aptamer; a primary antibody that binds to biomarkers, including but not limited to, EpCAM, AMACR, Androgen receptor, CD146, CD227, CD235, CD24, CD30, CD44, CD45, CD56, CD71, CD105, CD324, CD325, CD133, CAIX, MUC1, CEA, cMET, EGFR, Folate receptor, HER2, Mammaglobin, or PSMA; a ligand, such as EGF, HGF, TGFα, TGFβ superfamily of ligands, IGF1, IGF2, Wnt signaling proteins, FGF signaling ligands, amphiregulin, HB-EGF, neuregulin signaling ligands, MSP, VEGF family of ligands, betacellulin, epiregulin, epigen, hedgehog signaling ligands; IgG, IgM; scFv, Fab, sdAb; an antibody-like molecule that binds to a biomarker; or a second antibody.
The first and second molecules are complementary molecular conjugates that will indirectly bind and attach any particle to which they are already attached by binding and attaching to each other. The second molecule may include, but is not limited to, an avidin, such as streptavidin or neutravidin; Protein A, Protein G, Protein L; biotin; an aptamer; a primary antibody that binds to biomarkers, including but not limited to, EpCAM, AMACR, Androgen receptor, CD146, CD227, CD235, CD24, CD30, CD44, CD45, CD56, CD71, CD133, CD324, CD325, CAIX, MUC1, CEA, cMET, EGFR, Folate receptor, HER2, Mammaglobin, or PSMA; a ligand, such as EGF, HGF, TGFα, TGFβ superfamily of ligands, IGF1, IGF2, Wnt signaling proteins, FGF signaling ligands, amphiregulin, HB-EGF, neuregulin signaling ligands, MSP, VEGF family of ligands, betacellulin, epiregulin, epigen, hedgehog signaling ligands; IgG, IgM; scFv, Fab, sdAb; an antibody-like molecule that binds to a biomarker; or a second antibody.
On a doubly-conjugated ligand, the third molecule may include, but is not limited to, a fluorescent marker; alkaline phosphatase; an avidin, such as streptavidin or neutravidin; Protein A, Protein G, Protein L; biotin; an aptamer; a primary antibody that binds to biomarkers, including but not limited to, EpCAM, AMACR, Androgen receptor, CD146, CD227, CD235, CD24, CD30, CD44, CD45, CD56, CD71, CD105, CD324, CD325, MUC1, CEA, cMET, EGFR, Folate receptor, HER2, Mammaglobin, or PSMA; a ligand, such as EGF, HGF, TGFα, TGFβ superfamily of ligands, IGF1, IGF2, Wnt signaling proteins, FGF signaling ligands, amphiregulin, HB-EGF, neuregulin signaling ligands, MSP, VEGF family of ligands, betacellulin, epiregulin, epigen, hedgehog signaling ligands; IgG, IgM; scFv, Fab, sdAb; an antibody-like molecule that binds to a biomarker; or a second antibody.
The first and second intermediaries may include, but are not limited to an avidin, such streptavidin or neutravidin; biotin; a protein; an antibody, including but not limited to, EpCAM, AMACR, Androgen receptor, CD146, CD227, CD235, CD24, CD30, CD44, CD45, CD56, CD71, CD105, CD324, CD325, MUC1, CEA, cMET, EGFR, Folate receptor, HER2, Mammaglobin, or PSMA; a ligand, such as EGF, HGF, TGFα, TGFβ superfamily of ligands, IGF1, IGF2, Wnt signaling proteins, FGF signaling ligands, amphiregulin, HB-EGF, neuregulin signaling ligands, MSP, VEGF family of ligands, betacellulin, epiregulin, epigen, hedgehog signaling ligands; or an aptamer.
The foregoing description, for purposes of explanation, used specific nomenclature to provide a thorough understanding of the invention. However, it will be apparent to one skilled in the art that the specific details are not required in order to practice the invention. The foregoing descriptions of specific embodiments of the present invention are presented for purpose of illustration and description. They are not intended to be exhaustive or to limit the invention to the precise forms disclosed. Many modifications and variations are possible in view of the above teachings. The embodiments are shown and described in order to best explain the principles of the invention and its practical applications, to thereby enable others skilled in the art to best utilize the invention and various embodiments with various modifications as are suited to the particular use contemplated. It is intended that the scope of the invention be defined by the following claims and their equivalents:
This application claims the benefit of Provisional Application No. 61/641,169, filed May 1, 2012, which is hereby incorporated by reference in its entirety.
Number | Date | Country | |
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61641169 | May 2012 | US |