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Light Scattering

For information on access fees, policies and getting started at the CMI, see the CMI Access Page.

The CMI offers Training/Access on SEC-MALS, Mass Photometry and DLS instruments and select Data Collection Services.  

Size exclusion chromatography with multi-angle static light scattering (SEC-MALS) is used to accurately measure weight-averaged masses (Mw) of macromolecules in solution by measure the intensity of scattered light of a sample as it elutes from an SEC column.  

Mass Photometry (MP) is a single-particle light scattering method used to measure mass of macromolecules in solution, >30 KDa and for which standards with a shared refractive index are known (e.g. Protein or DNA).

Dynamic Light Scattering (DLS) measures the time-dependent fluctuations in scattered light. These fluctuations are directly related to rate of diffusion of the molecule through the solvent, and can be used to measure hydrodynamic radius (Rh) of the particles in solution. ​​​​​​

 

See also: molecular properties, Light Scattering

Light Scattering Data Collection Services

Light Scattering Services Description

In addition to instrument training, the CMI is now offering basic Light Scattering Data Collection services, including:

Static Light Scattering: SEC-MALS or Mass Photometry

  • mass determination in solution
  • oligomeric state

Dynamic Light Scattering

  • hydrodynamic radius
  • buffer optimization

Mass Photometry Service Overview

Mass Photometry

CMI Refeyn Two MP

Standard Mass Photometry Service

For proteins and protein complexes at least 30 KDa, without high molecular weight modifiers (modifiers of mass >5% total).  

  • Detector calibration with your buffer using a protein standard
  • Basic Data Analysis, in triplicate, 
    • Mass for each major peak
    • Population distribution of major peaks

AAV Mass Photometry Services

For AAVs (replication-incompetent, ~3-5 MDa). Requires Empty Capsid control, provided by the user.

Empty/Full Service

  • Detector calibration with your buffer using a protein standard
  • Basic AAV Analysis, in triplicate,
    • Empty/Full population distribution

AAV Extended Service

  • Detector calibration with your buffer using a protein standard and a DNA standard on poly-lysine coated slides
  • Extended AAV Analysis, in triplicate,
    • Empty/Full population distribution
    • Mass calculated for DNA cargo

SEC-MALS Service Overview

Size-exclusion Chromatography with Multi-Angle Light Scattering (SEC-MALS)

CMI SEC-MALS System: Wyatt Dawn Heleos with in-line DLS, RI UV, Agilent chromatography

Standard SEC-MALS Service

for proteins and protein complexes between 15 KDa and 1 MDa.  Prior purification by size-exclusion chromatography (SEC) is strongly recommended.  

Includes:

  • Column equilibration with your buffer (pH at or below pH 7.5) or with PBS
  • BSA Standard to test column performance and normalize detectors
  • SEC separation of your protein sample(s)
  • Basic Data analysis, including:
    • Molar Mass for each major peak
    • Hydrodynamic Radius from DLS (when light scattering signal is sufficient)

Additional Services

  • Protein Conjugate Analysis
    • required for samples with high molecular weight modifiers, such as glycosylation or detergent micelle (modifiers of mass >5% total)
    • requires modifier dn/dc
  • dn/dc measurements of detergent or protein samples

DLS Service Overview

Dynamic Light Scattering (DLS)

CMI DLS Instrument: Wyatt Dyanpro Plate Reader III

 

Standard DLS Service

For proteins and biopolymers up to 1000 nm in diameter. Includes:

  • Cumulants and Regularization fit of Hydrodynamic Radius (Rh), 1 nm - 1000 nm
  • Polydispersity Analysis

Additional Services

  • Aggregation Analysis - Small molecule
  • Buffer optimization

 

Data Collection Fees Summary

Data Collection

  • Limited Data Collection Services are offered.
  • Service fees are based on labor and supplies costs, and will be charged for all completed services, regardless of experimental outcome. 
  • Before submitting samples for data collection, users must approve the estimated charges and be given a date and time for sample delivery.
    • External Users will also be required to submit a PO and a signed CMI User Agreement.
  • Most CMI Data Collection Services include a setup fee plus a per-sample data collection fee.
    • Some services include replicate measurements by default in the per-sample fee. For others, there is a reduced-price replicate measurement fee, if collected in the same dataset.
  • Nanobody services not available to commercial users at this time.
  • Current Harvard Life Lab commercial users are offered a 25% discount off the standard commercial rates.

All Data Collection Fees