The Amicon Ultra 4 is a specialized laboratory device designed for separating and concentrating biological samples, preparing them for subsequent analysis in various scientific research fields. This single-use device is supplied with a cap, a filter device, and a centrifuge tube.
How Amicon Ultra 4 Works
The Amicon Ultra 4 operates on the principle of ultrafiltration, which separates molecules based on their size using a semi-permeable membrane and centrifugal force. The device contains an Ultracel regenerated cellulose membrane, characterized by a specific molecular weight cut-off (MWCO). This MWCO indicates the membrane’s ability to retain molecules above a certain molecular weight, ensuring that smaller molecules and solvents pass through while larger molecules are retained.
When a sample is added to the Amicon Ultra filter device, it is placed into a centrifuge rotor, typically a swinging-bucket rotor, and spun at a specified relative centrifugal force. The centrifugal force drives the solvent and smaller molecules through the membrane, collecting them as filtrate in the centrifuge tube. Larger molecules, such as proteins or nucleic acids, are retained above the membrane, forming a concentrated sample. The vertical design of the membrane minimizes solute polarization, and a physical deadstop prevents the device from spinning to dryness.
Key Uses in Research
The Amicon Ultra 4 is used in research for sample preparation applications, including protein concentration, buffer exchange, desalting, and removal of contaminants. It is used to concentrate dilute protein solutions, which is necessary for techniques like protein crystallization or structural analysis. The device can achieve high concentration factors, up to 80-fold, with processing times ranging from 10 to 40 minutes, depending on the membrane’s MWCO.
The device also facilitates buffer exchange, a process where the chemical environment of a sample is changed. This is accomplished by concentrating the sample and then reconstituting it with a new buffer, a process that can be repeated to reduce the concentration of unwanted microsolutes. Desalting, which involves removing salts from a sample, is another application, preparing samples for analyses such as mass spectrometry. Additionally, the Amicon Ultra 4 is effective for removing primers, linkers, or molecular labels from reaction mixes and purifying macromolecular components from tissue culture extracts or cell lysates.
The Impact on Scientific Progress
Tools like the Amicon Ultra 4 play a role in advancing scientific research by enabling efficient and reliable sample preparation. By providing scientists with purified and concentrated samples, these devices accelerate various research fields. This includes drug discovery, where concentrated proteins are needed for screening and characterization, and vaccine development, which requires purified viral particles or antigens.
The ability to effectively prepare samples also supports fundamental biological research, allowing for a deeper understanding of disease mechanisms and cellular processes. For instance, in forensic science, Amicon Ultra 4 devices are used to concentrate DNA extracted from bone samples, removing PCR inhibitors and improving the quality of genetic analysis. While seemingly small, these laboratory devices contribute to the speed and accuracy of scientific discoveries, providing a foundation for complex analyses and breakthroughs.