Dipanwita Batabyal, Harrison Lord, and Mats Wikström, Attribute Sciences, Amgen Inc.
Libo Wang, John Linnan, and Jeffrey Zonderman, RedshiftBio
Microfluidic Modulation Spectroscopy (MMS) is a novel automated infrared (IR) spectroscopic protein characterization technique to characterize the secondary structure of proteins. To assess the sensitivity of this technique, we first analyzed a monoclonal antibody (mAb) sample at low and high concentrations (0.5mg/ml and 10mg/ml) and compared the data to the traditional FTIR data. We also ran a BiTE sample (Bispecific T cell Engager) to test sensitivity for a different modality at low concentrations (1mg/ml). The high similarity scores (>98%) of both the samples at low concentrations indicate the high accuracy and sensitivity of this MMS method. To evaluate data quality and performance of the technique, we analyzed a mAb sample in three buffers containing different amounts of polysorbate (PS) 80 (0.01%, 0.05%, and 0.1%w/v). The results show that the absolute and second derivative spectra are closely matched in each buffer condition with similarity scores >99%. The HOS analysis yields consistent secondary structure content for the mAb sample in different buffers, indicating that different amounts of PS 80 in the buffers did not affect the secondary structure of the mAb sample. To test consistency, reproducibility and accuracy, the dataset was compared to the spectra of the same mAb at higher concentrations without PS80, with runs performed on different days. The high similarity scores (>99%), and consistent HOS analysis of secondary structure across different datasets confirm that PS 80 has no effect on the secondary structure of the mAb.