Stability may be considered one of the most important structural characteristics to monitor during development and formulation since it directly relates to the function of a biotherapeutic. When the secondary conformation of a protein changes, the active sites could be affected, oftentimes detrimentally. Using the Apollo or AQS³pro to monitor the stability of a protein over an experimental set of conditions is simple and intuitive. By tracking specific wave numbers that are associated with characteristic secondary structural features and calculating a “similarity score” or using weighted spectral difference, it is possible to observe if a protein changes its conformation which may indicate degradation, denaturation, or possibly aggregation.
Analyzing samples using the AQS³pro powered by Microfluidic Modulation Spectroscopy (MMS) provides a level of sensitivity that is unrivaled. Enhanced second derivative results are generated from the Absolute Absorbance spectra and further converted to a Delta plot highlighting subtle changes in the secondary structure. This enables early action to inform decisions for upstream development modifications and downstream formulation workflow optimization.