Applied Photophysics - For Circular Dichroism and Stopped-flow Spectroscopy

Chirascan™-plus Dynamic Multi-mode Spectroscopy (DMS)

Chirascan-plus circular dichroism spectromter

Introduction to Dynamic Multi-mode Spectroscopy (DMS)

"A stable, correctly-folded protein is an absolute requirement for a successful biotherapeutic and the stability of a desired conformation is determined by suitable formulation."

Chirascan-plus dynamic multi-mode spectroscopy (DMS) is a new technology from Applied Photophysics that uses multiple spectroscopic probes to monitor changes in secondary structure as a function of temperature and to determine the thermodynamics of unfolding. Chirascan DMS will:

  • Prove that a protein is initially correctly folded and hence biologically active
  • Distinguish between unfolding and aggregation steps, which is of potential relevance to future immunogenicity
  • Identify the structural components that change and the order in which they denature, giving valuable information on conformation
  • Determine quantitatively the Tm and enthalpy values as indicators of stability

The stability of a protein therapeutic is conventionally monitored by calorimetric techniques, particularly differential scanning calorimetry (DSC), yielding thermodynamic parameters such as the enthalpy and the mid-point of a conformational transition. The thermodynamic parameters are indicative of the relative stabilities of proteins in different conditions but calorimetric techniques cannot tell you how the conformation changes, whether or not a conformational change leads to aggregation, or if the protein is in its desired conformation prior to heating.

Knowledge of secondary structure will confirm whether or not the protein is correctly folded initially and observing the secondary structure as a function of temperature will tell you how its conformation changes on heating. However, the only common method to determine protein secondary structure in solution is circular dichroism (CD) and monitoring CD as a function of temperature can be a time-consuming business.

Chirascan dynamic multi-mode spectroscopy combines the benefits of spectroscopic and calorimetric measurements into a single, rapid, information-rich measurement that generates results from a complete experiment in about an hour.

Chirascan™plus DMS is available from Applied Photophysics as a package comprising of a Chirascan™-plus circular dichroism spectrometer with the following additional components:

  • Chirascan™-plus solid-state detector.
  • Multi-channel detection as standard.
  • High sensitivity total fluorescence detector as standard.
  • PCS.3 Peltier temperature control unit with custom cell cartridges.
  • A range of standard and custom cuvettes.
  • Chirascan™ Pro-Data software.
  • Global3 - global analysis software for multi-wavelength thermal studies.

An Introduction to Dynamic Multi-mode Spectroscopy (DMS)

This technical note describes the technique of Dynamic Multi-mode Spectroscopy in more detail.

Below are two application notes which describe DMS in more detail and demonstrate DMS in action.

A new approach for optimizing biotherapeutic formulation using Chirascan Dynamic Multi-mode Spectroscopy (DMS)

In this study, DMS is applied to the denaturation of a monoclonal antibody under different pH conditions to show the potential of the technology in biotherapeutic development.

The thermal denaturation of an oligonucleotide: a study to validate dynamic multimode spectroscopy.

In this study, an oligonucleotide is used to compare results from DMS and DSC and to demonstrate that the technique is reliable, reproducible and accurate.