Cell separation medias are used in biomedical research, diagnostic, and pharmaceutical applications for the isolation and purification of specific cell populations. These media facilitate the separation of target cells from a complex mixture, such as whole blood or tissue samples, based on specific characteristics or markers. The method of density gradient centrifugation separates specific cell populations of biological particles based on the density range of the gradient media and sample particles. The process of cell separation is crucial in various areas of pharmaceutical research and development, including drug discovery, immunotherapy, regenerative medicine, and stem cell research.
We offer a broad portfolio of density gradient media for the separation or extraction of leukocytes, viruses, DNA, RNA, organelles and many other applications. Our product line includes Histopaque® iodinated gradient media for the separation of leukocytes, polysaccharides for mammalian cell isolation, colloidal silica media for mammalian cell and organelle isolation, and inorganic salts for the isolation of DNA, viruses and proteins.
The popular ACCUSPIN™ System with Histopaque®-1077 uses radiation sterilized centrifuge tubes designed to create two separate chambers with a porous high-density polyethylene barrier ("frit"). This system allows the addition of anticoagulated whole blood to the upper chamber without risk of mixing with the Histopaque® separation media in the lower chamber. Histopaque® density grade media allows a clear separation of lymphocytes and mononuclear cells (i.e., monocytes). Erythrocytes aggregate and granulocytes become slightly hypertonic, increasing their sedimentation rate which results in pelleting at the bottom of the ACCUSPIN™ tube. Once the separation process is complete, the isolated cells can be further characterized, cultured, analyzed, or used in downstream applications such as flow cytometry, cell-based assays, molecular analysis, pharmaceutical or cell therapy development.
Histopaque® media is designed to separate different cell types based on their density and is commonly used in pharmaceutical and biomedical research for the isolation and purification of specific cell populations. Histopaque® media are sterile-filtered, endotoxin-tested solutions of polysucrose and sodium diatrizoate, adjusted to precise densities. These ready-to-use separation media facilitate the rapid and optimal recovery of viable cells from small volumes of whole blood. Histopaque® separation media are typically used in applications such as: Peripheral blood mononuclear cell (PBMC) isolation: Histopaque® media is often employed to isolate PBMCs from whole blood samples. PBMCs consist of lymphocytes, monocytes, and other nucleated cells. By layering the Histopaque® medium between the blood sample and a centrifuge tube, centrifugation causes the separation of PBMCs from other blood components, such as red blood cells and platelets. Cell fractionation: Histopaque® media can be used to fractionate mixed cell populations into distinct layers based on their density. By layering the separation medium in a centrifuge tube and carefully adding the cell suspension, centrifugation causes the formation of distinct layers representing different cell types. This technique is useful for separating and purifying cells for further analysis or experimentation. Isolation of specific cell types: Histopaque® separation media can be utilized to isolate specific cell populations based on their density or specific markers. By carefully layering the separation medium and the cell suspension, centrifugation separates the cells of interest from unwanted cells. This technique is particularly valuable for researchers studying specific cell types or seeking to enrich rare cell populations. Produced under ISO 9001 quality management, Histopaque® products with lot-specific performance testing provide consistently selective separation of blood cell lines, optimal separation of viable undistorted cells and minimal extraneous cell interference.
Colloidal silica media are colloidal suspensions of silica particles coated with polyvinylpyrrolidone (PVP) with a diameter of 15-30 nm typically used in biomedical and pharmaceutical research for cell separation and purification. PVP decreases the particle interactions with the biological material and stabilizes the colloid in an isotonic saline solution.. Its density can be adjusted by changing the concentration of the Percoll® solution, allowing researchers to customize the gradient to suit their specific separation needs. Our Percoll® colloidal media has extremely low osmotic strength that changes little with density. Also, the osmolality of the gradients formed by centrifugation are adjusted easily by adding appropriate amount of sucrose or buffer solution. The Percoll® gradients are ideal for the isopycnic separations of cell, organelles, membrane vesicles, and even some viruses.
Ionic gradient media, also known as ionic gradients or ionic solutions, are used in cell separation techniques to separate cells based on their surface charge or electrical properties. These media create an electrostatic field or charge differential, which enables the separation of cells with different surface charges. Examples of cell separation techniques that utilize ionic gradient media include electrophoresis, dielectrophoresis (DEP), and isoelectric focusing (IEF). The specific choice of media and technique depends on the nature of the cells being separated, the desired separation mechanism, and the overall experimental objectives. Our ionic gradient media, comprised of concentrated heavy metal salts, are exclusively used for isopycnic separations of nucleic acids. Cesium chloride and cesium sulfate are the most widely used heavy metal salts with gradient densities of up to 1.91 g/cm3. Other salts used include sodium iodide, sodium bromide and the rubidium salts. The selection and design of ionic gradient media and techniques require careful consideration of factors such as pH, conductivity, buffer composition, and the electrical properties of the cells under investigation.
Nonionic iodinated density gradient media are specialized substances used for separation and purification techniques in various fields, including biology, biochemistry, and clinical diagnostics. These media are typically based on iodinated compounds that form density gradients, allowing the separation of particles based on their density. Nonionic iodinated density gradient media operate on the principle of density gradient centrifugation. The structures of most iodinated compounds used in the popular density gradient media are based on iodinated compounds like tri-iodobenzoic acid with a hydrophilic group attached to increase their solubility to form a continuous density gradient in aqueous solution. We provide denser iohexol solutions (e.g., Nycodenz® and Histodenz™) that minimize the dehydration of biological particles. Iohexol is nontoxic and not metabolized by mammalian cells.
Our portfolio of polyhydric alcohol nonionic gradient media includes sucrose gradients that are widely used for the rate-zonal separation of macromolecules and for isopycnic separation of viruses and cell organelles. The advantages include their stable nature, inertness and low cost; whereas the disadvantages involve the concentrated and hypertonic nature of the solution. We also offer glycerol solution having lesser density than the corresponding sucrose solutions, thereby preventing the activity of certain enzymes while being removed easily through vacuum.
We provide the mostly commonly used polysaccharide medium, Ficoll® to circumvent the high osmotic strength issues arising with the use of sucrose solutions. Ficoll® synthetic polymers are polyvinylpyrrolidone-coated poly(ethylene glycol) (PEG) commonly used to prepare density gradient solutions. Ficoll® solutions are widely utilized in various biological and biochemical applications, particularly for cell separation and isolation. It The solution isis produced by the polymerization of sucrose molecules with epichlorohydrin to give a polysaccharide with the average molecular weight of 400,000. Ficoll® solutions below 20%(w/v) have a density of 1.07 g/cm3 and are considered osmotically inert. The main disadvantage of Ficoll® solution lies in its more viscous nature than the comparable sucrose solutions. Ficoll® solutions play a significant role in various pharmaceutical research and development processes, facilitating the isolation, purification, and characterization of cells, viruses, and other biological components, thereby contributing to advancements in drug discovery, immunotherapy, and other pharmaceutical applications. They are commonly employed in cell separation techniques, especially for isolating mononuclear cells from peripheral blood or other cell sources. By layering the cell suspension onto a Ficoll® density gradient and centrifuging, cells of interest, such as lymphocytes or monocytes, can be separated from other cell types and unwanted components like red blood cells and granulocytes. Ficoll® solutions are also used in density gradient centrifugation, a technique that separates particles or molecules based on their buoyant density. During centrifugation, particles or cells migrate through the Ficoll® gradient, settling at positions that correspond to their respective densities. This allows for the separation and fractionation of different components present in a heterogeneous mixture.
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