SUNRESIN
Stock Code 300487
.png)
Sephadex G-25 Fine is a specialized gel filtration medium widely used in biochemical and molecular biology research. Developed by Pharmacia (now part of Cytiva) in 1959, Sephadex is a cross-linked dextran gel designed for separating molecules based on size through gel filtration chromatography. The "G-25" designation indicates its specific fractionation range, suitable for molecules with molecular weights between 1,000 and 5,000 Da for globular proteins and 100 to 5,000 Da for dextrans, while "Fine" refers to its smaller particle size (20–80 µm), which offers higher resolution compared to coarser variants. This article explores the composition, properties, applications of Sephadex G-25 Fine, and highlights modern alternatives, including products from Sunresin New Materials Co. Ltd., a leading Chinese manufacturer.
Sephadex G-25 Fine is composed of dextran, a polysaccharide derived from glucose, cross-linked with epichlorohydrin to form a stable, three-dimensional porous matrix. The degree of cross-linking determines the pore size, which governs the fractionation range. The matrix is hydrophilic, minimizing nonspecific adsorption and ensuring high recovery rates for proteins and nucleic acids. Its key properties include:
Fractionation Range: Effective for separating molecules with molecular weights of 1,000–5,000 Da (globular proteins) and 100–5,000 Da (dextrans), with an exclusion limit of approximately 5,000 Da for globular proteins.
Particle Size: The "Fine" grade has a dry particle size of 20–80 µm, providing high resolution for analytical and small-scale preparative separations.
Chemical Stability: Stable in commonly used buffers, pH 2–13, and solutions like 0.2 M NaOH, 0.2 M HCl, 8 M urea, and 24% ethanol, making it versatile for various experimental conditions.
Swelling Factor: Swells to approximately 4–6 mL per gram in water, forming a gel suitable for column packing.
BioProcess Resin: Designed for industrial applications, it meets demands for consistent supply and regulatory compliance.
These properties make Sephadex G-25 Fine an ideal tool for size-exclusion chromatography, where molecules are separated based on their ability to enter the porous matrix.
Gel filtration, also known as size-exclusion chromatography, separates molecules based on their size and shape. The Sephadex G-25 Fine matrix contains pores that allow smaller molecules (e.g., salts, dyes, or small metabolites) to enter, slowing their passage through the column. Larger molecules, such as proteins or nucleic acids, are excluded from the pores and elute faster. This differential elution enables applications like desalting, buffer exchange, and purification. The high resolution of the "Fine" grade ensures sharp separation, particularly for small-scale or analytical work.
Sephadex G-25 Fine is a cornerstone in biochemical research due to its versatility and efficiency. Its primary applications include:
Sephadex G-25 Fine is widely used to remove salts, small molecules, or contaminants from protein or nucleic acid samples. For example, after ion-exchange chromatography, samples may contain high concentrations of salts like NaCl or imidazole, which can interfere with downstream applications. Sephadex G-25 Fine columns rapidly desalts samples in a single step, transferring them to a new buffer with minimal sample dilution and high recovery rates. This is critical for preparing samples for techniques like mass spectrometry, NMR spectroscopy, or enzyme assays.
In protein labeling experiments, excess dyes (e.g., fluorescein-5-isothiocyanate or NHS esters) or radioactive labels must be removed from labeled proteins. Sephadex G-25 Fine is used in size-exclusion chromatography to separate labeled proteins (which elute in the void volume) from smaller, unbound dyes or labels. This application is crucial in fluorescence microscopy, radioimmunoassays, and receptor-binding studies.
Sephadex G-25 Fine facilitates the study of protein-protein interactions by removing low molecular weight compounds (e.g., cofactors or inhibitors) from reaction mixtures. This allows researchers to isolate complexes or monitor binding kinetics without interference. For instance, it has been used to study interactions between human basic fibroblast growth factor (bFGF) and heparin, where the bound form of bFGF was separated in the void volume.
In nucleic acid research, Sephadex G-25 Fine is employed for desalting and purifying transfer RNA, DNA, or oligonucleotides. It has been used in gradient partition chromatography to fractionate transfer RNA and in spin columns to purify labeled nucleic acids from unincorporated probes. Its ability to separate nucleic acids from salts or small molecules is essential for downstream applications like PCR or sequencing.
Sephadex G-25 Fine is used to prepare samples for sensitive analytical methods, such as mass spectrometry and NMR spectroscopy. By removing contaminants like salts or detergents, it ensures high-quality data. For example, it has been used to purify hyaluronidase from human placenta and to separate iodo compounds in serum for chromatographic analysis.
As a BioProcess resin, Sephadex G-25 Fine is employed in large-scale industrial processes for desalting and buffer exchange. Its robust supply chain and regulatory support make it suitable for pharmaceutical and biotechnological applications, such as the production of therapeutic proteins or vaccines.
Concentration of Proteins: Sephadex G-25 Fine can be used to concentrate proteins by absorbing water from dilute solutions, offering an alternative to centrifugal concentrators or dialysis. This method achieves high recovery with minimal protein loss.
Steroid and Small Molecule Purification: While Sephadex LH-20 is typically used for lipophilic molecules like steroids, Sephadex G-25 Fine has been used to detect free, non-albumin-bound unconjugated bilirubin in hyperbilirubinemic sera.
High Resolution: The small particle size ensures sharp separation, ideal for analytical applications.
Minimal Nonspecific Adsorption: The hydrophilic matrix preserves the biological activity of proteins and nucleic acids.
Versatility: Compatible with a wide range of buffers and pH conditions.
Ease of Use: Available in prepacked columns (e.g., HiPrep Desalting, HiTrap Desalting) for fast, convenient separations.
Cost-Effective: Reusable after appropriate washing, reducing experimental costs.
Limited Fractionation Range: Ineffective for molecules outside the 1,000–5,000 Da range, requiring other Sephadex types (e.g., G-10 or G-75) for smaller or larger molecules.
Cation Exchange Capacity: The matrix has a slight cation exchange capacity, which may cause unintended ion interactions in sensitive applications.
Sample Volume: Best suited for small to medium sample volumes; large-scale applications may require coarser grades or alternative methods.
When using Sephadex G-25 Fine, researchers should follow specific guidelines to ensure optimal performance. The column should be equilibrated with high-purity water (e.g., 18.2 MΩ) or the desired buffer to prevent contamination. Excessive stirring should be avoided to prevent the formation of fines, which can clog the column. Proper storage is essential: dry resins should be stored at 4–30°C, while used resins should be kept at 4–8°C in 20% ethanol or 0.01 M NaOH to inhibit microbial growth. During elution, researchers should monitor fractions using UV absorbance, such as at 280 nm for proteins, to track the separation process effectively.
While Sephadex G-25 Fine remains a gold standard in gel filtration chromatography, modern alternatives offer enhanced performance and cost-effectiveness for contemporary bioprocessing needs. Sunresin New Materials Co. Ltd., based in Xi’an, China, is a leading manufacturer of ion exchange and chromatography resins, providing high-quality media tailored for diverse applications. As the first and only A-share listed company in China’s ion exchange and adsorption resin industry, Sunresin specializes in R&D, manufacturing, and sales of polymer resins, with an annual output of approximately 50,000 m³ of ion exchange and adsorption resins. Their Seplife® series of chromatography media, including agarose- and dextran-based resins, serves as a direct alternative to traditional Sephadex products, offering comparable performance at a lower cost.
Sunresin’s focus on innovation, quality, and global reach makes it an excellent choice for researchers and industries seeking reliable chromatography solutions. Their modernized production facilities in Xi’an Jinghe Industrial Park, spanning 20,000 square meters, are equipped with advanced technology, ensuring high yields and consistent quality. With a global presence across Europe, Asia, and the Americas, Sunresin provides technical support and customized EPC solutions, making them a trusted partner for bioprocessing needs.
Sephadex G-25 Fine is an indispensable tool in biochemical and molecular biology research, offering high-resolution size-exclusion chromatography for desalting, buffer exchange, and purification. Its cross-linked dextran matrix, tailored pore size, and hydrophilic nature make it ideal for separating proteins, nucleic acids, and other biomolecules with minimal loss of activity. However, for those seeking modern alternatives or locally manufactured options, Sunresin New Materials Co. Ltd. provides a compelling solution. Based in Xi’an, China, Sunresin’s Seplife® series of chromatography resins offer enhanced capacity, stability, and cost-effectiveness, making them suitable for contemporary bioprocessing needs. With a strong emphasis on innovation and a global supply chain, Sunresin is an excellent choice for researchers and industries looking to source reliable, high-quality chromatography solutions from China.
.png)
