Composition-Gradient, Multi-Angle Static Light Scattering (CG-MALS) is a powerful technique for characterizing a wide range of biomolecular interactions. Composition-Gradient Multi-Angle Light Scattering (CG-MALS) employs a series of unfractionated samples of different composition or concentration in order to characterize a wide range of macromolecular interactions. No special modifications (e.g., sample tagging or immobilization procedures) are necessary: samples are unlabeled and entirely in solution.

CG-MALS employs a Calypso® connected to a MALS instrument and optional concentration detector. The Calypso performs sample preparation and delivery, combining up to three different solution in precise mixing ratios and injecting into the detectors.

Accurate compositions result from setting the Calypso’s pumps to appropriate flow rate ratios, all controlled from the CALYPSO™ software through an intuitive GUI. Mixing is achieved by dispensing the solutions simultaneously from all three pumps via a static mixer.

Reliable light scattering measurement require the samples to be degassed and filtered. The Calypso incorporates built-in, low-volume degassers and filter housings, connected via PEEK tubing and finger-tight fittings. Even the filter housing is finger-tight, making use of a proprietary design for maximum convenience.

Calypso Features
  • Biocompatible wetted materials
  • Flexibility to re-organize fluid paths and utilize different wetted materials as needed
  • Convenient loading of sample and diluent solutions via conical tubes: 5, 15 or 50 mL
  • Autoinject Out contact closure signal, to trigger data acquisition by ASTRA® or DYNAMICS® software for data acquisition and analyses not supported by the CALYPSO software (e.g., DLS acquisition)
  • Built-in Wash port, allowing the pumps to draw on reservoirs of wash solutions for post-experimental clean-up. Automation of up to two sequential wash solutions, e.g. buffer (to clean out proteins) followed by water (to clean out buffer salts) or detergent followed by water, is possible when an Orbit™ solvent selector valve is added to the setup. These operations are appended to the Method for unattended operation
Some additional Calypso features

The layout and design were fine-tuned to reduce sample use while enhancing automation and maintaining compatibility with the DAWN and miniDAWN, the ultimate in MALS detectors. Special features of the Calypso include:

  • Most tubing is 0.010″ (0.25 mm) i.d. PEEK for biocompatibility and low volume. May be changed to PTFE or stainless steel for non-aqueous solutions, and larger i.d. for viscous solutions
  • A range of syringe sizes to meet specific needs
  • In-line degassing of samples and buffers
  • Easy access to all tubing and filters, for rapid maintenance
  • Pressure warnings indicate when a filter membrane is saturated or a capillary tube clogged

Recognizing that CG-MALS is unfamiliar territory for most users, we’ve also developed Tutorials, Application Guides, Method Templates, and additional support literature and training to help you get started and keep you on track. Make the most of this amazingly powerful technique – we’re here to help at every turn.